GMC Powertrain 4.3 L User manual

Engine
Engine Model:
General Motors 4.3 L Powertrain
Generator Models:
30--45 kW
TP-6103 1/01
Service

CAUTION
Caution: In order to reduce the chance of personal injury and/or property damage, carefully observe the instructions
that follow.
The service manual of General Motors Powertrain is intended for use by professional, qualified technicians.
Attempting repairs or service without the appropriate training, tools, and equipment could cause injury to you or others,
damage the equipment, or cause the equipment to operate improperly.
Proper equipment and repair are important to the safety of the service technician and to the safe, reliable operation of
the equipment. If you need to replace a part, use the same part number or an equivalent part. Do not use a
replacement part of lesser quality.
The service procedures we recommend and describe in this service manual are effective methods of performing
service and repair. Some of the procedures require the use of tools that are designed for specific purposes.
Accordingly, any person who intends to use a replacement part, a service procedure, or a tool that is not recommended
by General Motors Powertrain must first establish that there is no jeopardy to personal safety or the safe operation of
the equipment.
This manual contains various Cautions and Notices that you must observe carefully to reduce the risk of personal
injury during service or repair. Improper service or repair may damage the equipment or render the equipment unsafe.
These Cautions and Notices are not exhaustive. General Motors Powertrain cannot possibly warn of all the potentially
hazardous consequences of failure to follow these instructions.

TP-6103 1/01 Table of Contents
Table of Contents
Caution Inside Front Cover.....................................................................
Introduction i..................................................................................
Cautions and Notices I.........................................................................
Fastener Tightening Specifications 6-1.........................................................
Engine Mechanical Specifications 6-4..........................................................
GM SPO Group Numbers 6-6...................................................................
Sealers, Adhesives, and Lubricants 6-9.........................................................
Diagnostic Information and Procedures 6-10....................................................
Base Engine Misfire Diagnostic 6-10......................................................
Engine Compression Test 6-11...........................................................
Engine Noise Diagnostic 6-12............................................................
Valve Train Diagnosis 6-13..............................................................
Excessive Oil Consumption 6-15.........................................................
Oil Pressure Diagnosis and Testing 6-15..................................................
Oil Leak Diagnosis 6-16.................................................................
Drive Belts 6-18........................................................................
Drive Belt Chirping 6-18.................................................................
Drive Belt Squeal 6-20..................................................................
Drive Belt Whine 6-21..................................................................
Drive Belt Rumbling 6-22................................................................
Drive Belt Vibration 6--23................................................................
Drive Belt Falls Off 6--24.................................................................
Drive Belt Excessive Wear 6--25..........................................................
Drive Belt Tensioner 6-26...............................................................
Component Locator 6-28......................................................................
Intake Manifold 6-28....................................................................
Cylinder Head and Exhaust Manifold 6-30.................................................
Cylinder Block and Components 6-31.....................................................
Lower Engine Block and Oil Pan 6-33.....................................................
Repair Instruction—Removal 6-34..............................................................
Draining Fluids and Oil Filter Removal 6-34................................................
Engine Flywheel Removal 6-35..........................................................
Clutch Pilot Bearing Removal 6-35.......................................................
Exhaust Manifold Removal 6-36..........................................................
Oil Level Indicator and Tube Removal 6-37................................................
Water Pump Removal 6-38..............................................................
Crankshaft Balancer Removal 6-39.......................................................
Valve Rocker Arm Cover Removal 6-40...................................................
Distributor Removal 6-42................................................................
Intake Manifold Removal 6-43...........................................................
Valve Rocker Arm and Push Rod Removal 6-44............................................
Cylinder Head Removal 6-45............................................................
Valve Lifter Removal 6-50...............................................................
Oil Pan Removal 6-51..................................................................
Oil Pump Removal 6-52.................................................................
Engine Front Cover Removal 6-53........................................................
Timing Chain and Sprockets Removal 6-54................................................
Balance Shaft Removal 6-56............................................................
Camshaft Removal 6-57................................................................
Piston, Connecting Rod, and Bearing Removal 6-58........................................

TP-6103 1/01Table of Contents, continued
Table of Contents, continued
Crankshaft Rear Oil Seal Removal 6-59...................................................
Crankshaft and Bearings Removal 6-61...................................................
Engine Block Plug Removal 6-62.........................................................
Inspection 6-66...............................................................................
Engine Block Clean and Inspect 6-66.....................................................
Cylinder Boring and Honing 6-67.........................................................
Boring Procedure 6-68..................................................................
Piston and Connecting Rod Disassemble 6-69.............................................
Piston, Connecting Rod, and Bearings Clean/Inspect 6-70...................................
Piston Selection 6-73...................................................................
Piston and Connecting Rod Assemble 6-74................................................
Crankshaft and Bearings Clean and Inspect 6-76...........................................
Bearing Clearance Measuring Procedure 6-80.............................................
Crankshaft Balancer Clean and Inspect 6-86...............................................
Engine Flywheel Clean and Inspect 6-86..................................................
Camshaft and Bearings Clean and Inspect 6-88............................................
Camshaft Bearing Removal 6-89.........................................................
Camshaft Bearing Installation 6-91.......................................................
Balance Shaft Bearing and/or Bushing Removal 6-93.......................................
Balance Shaft Clean and Inspect 6-94....................................................
Balance Shaft Bearing and/or Bushing Installation 6-95.....................................
Timing Chain and Sprockets Clean and Inspect 6-96........................................
Valve Rocker Arm and Push Rods Clean and Inspect 6-96...................................
Valve Lifters and Guides Clean and Inspect 6-98...........................................
Cylinder Head Disassemble 6-99.........................................................
Cylinder Head Clean and Inspect 6-99....................................................
Valve Guide Reaming/Valve and Seat Grinding 6-102.......................................
Cylinder Head Assemble 6-104..........................................................
Oil Pump Disassemble 6-106............................................................
OIl Pump Clean and Inspect 6-108.......................................................
Oil Pump Assemble 6-109...............................................................
Valve Rocker Arm Cover Clean and Inspect 6-111..........................................
Oil Pan Clean and Inspect 6-112.........................................................
Intake Manifold Disassemble 6-113.......................................................
Intake Manifold Clean and inspect 6-117..................................................
Intake Manifold Assemble 6-118.........................................................
Exhaust Manifold Clean and inspect 6-123.................................................
Water Pump Clean and inspect 6-124.....................................................
Thread Repair 6-125....................................................................
Service Prior to Assembly 6-126.........................................................
Installation 6-128..............................................................................
Engine Block Plug Installation 6--128......................................................
Crankshaft and Bearings Installation 6-132................................................
Crankshaft Rear Oil Seal and Housing Installation 6-134....................................
Piston, Connecting Rod, and Bearing Installation 6-136.....................................
Balance Shaft Installation 6-139..........................................................
Timing Chain and Sprockets Installation 6-142.............................................
Engine Front Cover Installation 6-144.....................................................
Oil Pump Installation 6-145..............................................................
Oil Pan Installation 6-146................................................................
Crankshaft Balancer Installation 6-149....................................................
Valve Lifter Installation 6-151............................................................
Cylinder Head Installation 6-152..........................................................

TP-6103 1/01 Table of Contents, continued
Table of Contents, continued
Valve Rocker Arm and Push Rod Installation 6-157.........................................
Intake Manifold Installation 6-159.........................................................
Distributor Installation 6-161.............................................................
Valve Rocker Arm Cover Installation 6-164................................................
Oil Level Indicator and Tube Installation 6-166.............................................
Water Pump Installation 6-167...........................................................
Exhaust Manifold Installation 6-168.......................................................
Clutch Pilot Bearing Installation 6-169.....................................................
Engine Flywheel Installation 6-169........................................................
Engine Setup and Testing 6-171................................................................
Description and Operation 6-172...............................................................
Engine Component Description 6-172.....................................................
Drive Belt System Description 6-172......................................................
New Product Information 6-173..........................................................
Lubrication 6-175......................................................................
Cleanliness and Care 6-175.............................................................
Replacing Engine Gaskets 6-176.........................................................
Use of RTV and Anaerobic Sealer 6-176..................................................
Separating Parts 6-177.................................................................
Tools and Equipment 6-178..............................................................
Special Tools and Equipment 6-179.............................................................

TP-6103 1/01Table of Contents, continued

TP-6103 1/01 iIntroduction
Introduction
This service manual provides the service technician
with information to service the General Motors
Powertrain engines.
In general, this manual covers the service of the engine
and associated standard equipment. In some cases the
engine is supplied with accessories and equipment that
are unique to the application. If service information is
required on such unique accessories or equipment,
contact the generator set manufacturer who will forward
the proper information or advise the service technician
where it can be obtained.
The information in this manual is grouped in sections
according to the type of work being performed. The
various sections are indicated in the Table of Contents of
the manual.
This manual has been reprinted by the generator set
manufacturer with the permission of General Motors
Powertrain.
This manual is a reproduction of a General Motors
Powertrain publication and contains information
pertaining to industrial generator set engines. Some
information pertains to other applications of the engine.
The accuracy and completeness of information is the
sole responsibility of General Motors Powertrain.
The descriptions and specifications contained in this
manual were in effect at the time the book was released
by General Motors Powertrain. The generator set
manufacturer and General Motors Powertrain reserve
the right to discontinue models or change specs or
design at any time without notice and without incurring
obligation.

TP-6103 1/01ii Introduction
Notes

TP-6103 1/01 ISafety Precautions and Instructions
Cautions and Notices
Definition of Caution, Notice, and
Important
The diagnosis and repair procedures in the GM
Powertrain Service Manual contain both general and
specific Cautions, Notices, and Importants. GM
Powertrain is dedicated to the presentation of service
information that helps the technician diagnose and
repair the systems necessary for the proper operation of
the equipment; however, certain procedures may
present a hazard to the technician if they are not
followed in the recommended manner. Cautions,
Notices, and Importants are elements designed to
prevent these hazards; however, not all hazards can be
foreseen. This information is placed at strategic
locations within the service manual and is designed to
prevent the following:
DSerious bodily injury to the technician.
DDamage to the equipment.
DUnnecessary equipment repairs.
DUnnecessary component repairs.
DImproper repair or replacement equipment
components. Any caution or notice that appears in
general information is referenced from the individual
service categories.
Caution Defined
When encountering a Caution, you will be asked to take
a necessary action or avoid a prohibited action. If a
Caution is not heeded, the following consequences may
occur:
DSerious bodily injury to the technician.
DSerious bodily injury to other technicians in the
workplace area.
DSerious bodily injury to the equipment operator if the
equipment has been improperly repaired.
Notice Defined
Notices call special attention to a necessary action or to
a prohibited action. If a Notices not heeded, the
following consequences may occur:
DDamage to the equipment.
DUnnecessary equipment repairs.
DUnnecessary component replacement.
DImproper operation or performance of the system or
component under repair.
DDamage to any systems or components that are
dependent upon the proper operation of the system or
component under repair.
DImproper operation or performance of any systems or
components that are dependent upon the proper
operation or performance of the system or
component under repair.
DDamage to fasteners, basic tools, or special tools.
DLeaks of coolant, lubricant, or other vital fluids.
Important Defined
Important statements emphasize a necessary
characteristic of a diagnostic or repair procedure.
Important statements are designed to do the following:
DClarify a procedure.
DPresent additional information for accomplishing a
procedure.
DGive insight into the reason or reasons for performing
a procedure in the manner recommended.
DPresent information that will help to accomplish a
procedure in a more effective manner.
DPresent information that gives the technician the
benefit of past experience in accomplishing a
procedure with greater ease.

TP-6103 1/01II Safety Precautions and Instructions
Moving Parts and Hot Surfaces Caution
Caution: Avoid contact with moving parts and hot
surfaces while working around a running engine in order
to prevent physical injury.
Safety Glasses Caution
Caution: Always wear safety glasses to avoid eye
damage.
Belt Drive Notice
Notice: Do not use belt dressing on the drive belt. Belt
dressing causes the breakdown of the composition of
the drive belt. Failure to follow this recommendation will
damage the drive belt.
Component Fastener Tightening Notice
Notice: Replacement components must be the correct
part number for the application. Components requiring
the use of the thread-locking compound, lubricants,
corrosion inhibitors, or sealants are identified in the
service procedure. Some replacement components
may come with these coatings already applied. Do not
use these coatings on components unless specified.
These coatings can affect the final torque, which may
affect the operation of the component. Use the correct
torque specifications when installing components in
order to avoid damage.
Fastener Notice
Notice: Use the correct fastener in the correct location.
Replacement fasteners must be the correct part number
for that application. Fasteners requiring replacement or
fasteners requiring the use of thread-locking compound
or sealant are identified in the service procedure. Do not
use paints, lubricants, or corrosion inhibitors on
fasteners or fastener joint surfaces unless specified.
These coatings affect fastener torque and joint clamping
force and may damage the fastener. Use the correct
tightening sequence and specifications when installing
fasteners in order to avoid damage to parts and
systems.
Special Fastener Notice
Notice: This bolt is designed to permanently stretch
when tightened. The correct part number fastener must
be used to replace this type of fastener. Do not use a bolt
that is stronger in this application. If the correct bolt is
not used, the parts will not be tightened correctly. The
system or the components may be damaged.

Engine Marine/Industrial 4.3L 6-1
2000 Marine/Industrial
Engine Mechanical - 4.3L
Specifications
FastenerTightening Specifications
Specification
Application Metric English
Accelerator Control Cable Bracket Nut to Stud 12 N•m 106 lb in
Accelerator Control Cable Bracket Nut to Throttle Body 9 N•m 80 lb in
Accelerator Control Cable Bracket Stud to Intake Manifold 6 N•m 53 lb in
Accelerator Control Cable Bracket Stud to Throttle Body 12 N•m 106 lb in
Air Cleaner Adapter Stud 8 N•m 71 lb in
Balance Shaft Driven Gear Bolt
First Pass 20 N•m 15 lb ft
Final Pass 35 degrees
Balance Shaft Retainer Bolt 12 N•m 106 lb in
Battery Cable Bracket Bolt to Oil Pan 12 N•m 106 lb in
Battery Negative Cable Bolt to Engine 25 N•m 18 lb ft
Battery Positive Cable Junction Block Bracket Bolt 25 N•m 18 lb ft
Belt Idler Pulley Bolt 50 N•m 37 lb ft
Camshaft Retainer Bolt 12 N•m 106 lb in
Camshaft Sprocket Bolt 25 N•m 18 lb ft
Connecting Rod Nut
First Pass 27 N•m 20 lb ft
Final Pass 70 degrees
Crankshaft Balancer Bolt 95 N•m 70 lb ft
Crankshaft Bearing Cap (Preferred Method)
First Pass 20 N•m 15 lb ft
Final Pass 73 degrees
Crankshaft Bearing Cap Bolt 105 N•m 77 lb ft
Crankshaft Position Sensor Bolt 8 N•m 71 lb in
Crankshaft Pulley Bolt 58 N•m 43 lb ft
Crankshaft Rear Oil Seal Housing Bolt and Nut 12 N•m 106 lb in
Crankshaft Rear Oil Seal Housing Retainer Stud 6 N•m 53 lb in
Cylinder Head Bolt (Preferred Method)
All Bolts First Pass in Sequence 30 N•m 22 lb ft
Long Bolts Final Pass in Sequence 75 degrees
Medium Bolts Final Pass in Sequence 65 degrees
Short Bolts Final Pass in Sequence 55 degrees
Cylinder Head Core Hole Plug 20 N•m 15 lb ft
Distributor Cap Bolt 2.4 N•m 21 lb in
Distributor Clamp Bolt 25 N•m 18 lb ft
Drive Bolt Tensioner Bolt 50 N•m 37 lb ft
EGR Valve Bolt
First Pass 7 N•m 62 lb in
Final Pass 30 N•m 22 lb ft

6-2 Marine/Industrial 4.3L Engine
2000 Marine/Industrial
FastenerTightening Specifications (cont’d)
Specification
Application Metric English
EGR Valve Inlet Pipe Clamp Bolt 25 N•m 18 lb ft
EGR Valve Inlet Pipe Nut at Intake Manifold 25 N•m 18 lb ft
EGR Valve Inlet Pipe Nut at Exhaust Manifold 30 N•m 22 lb ft
Engine Block Left Side Oil Gallery Plug 20 N•m 15 lb ft
Engine Block Left Rear Oil Gallery Plug 30 N•m 22 lb ft
Engine Block Right Rear Oil Gallery Plug 20 N•m 15 lb ft
Engine Block Coolant Drain Hole Plug 20 N•m 15 lb ft
Engine Block Oil Gallery Plug 20 N•m 15 lb ft
Engine Coolant Heater Bolt/Screw 2 N•m 18 lb in
Engine Coolant Temperature (ECT) Sensor 20 N•m 15 lb ft
Engine Flywheel Bolt 100 N•m 74 lb ft
Engine Front Cover Bolt 12 N•m 106 lb in
Engine Lift Bracket Bolt (Special Tool J 41427) 15 N•m 11 lb ft
Engine Lift Front Bracket Stud 35 N•m 26 lb ft
Engine Mount Bolt to Engine Bracket 50 N•m 37 lb ft
Engine Mount Engine Bracket Bolt to Engine 50 N•m 37 lb ft
Engine Mount Frame Bracket Through-Bolt 75 N•m 55 lb ft
Engine Mount Frame Side Mount Bolt 65 N•m 50 lb ft
Engine Oil Level Sensor 13 N•m 115 lb in
Engine Oil Pressure Gauge Sensor 30 N•m 22 lb ft
Engine Oil Pressure Gauge Sensor Fitting (Plus Required Angle) 15 N•m 11 lb ft
Engine Wiring Harness Bracket Bolt to Battery Positive Cable Junction
Block Bracket 9 N•m 80 lb in
Engine Wiring Harness Bracket Bolt to Generator and Drive Belt
Tensioner Bracket 25 N•m 18 lb ft
Engine Wiring Harness Bracket Bolt to Rear Right Side Cylinder Head 25 N•m 18 lb ft
Engine Wiring Harness Bracket Nut to Evaporative Emission (EVAP)
Canister Purge Solenoid Valve Stud 9 N•m 80 lb in
Engine Wiring Harness Bracket Nut to Intake Manifold Stud 12 N•m 106 lb in
Evaporitive Emission (EVAP) Canister Purge Solenoid Valve Stud to
Intake Manifold 10 N•m 89 lb in
Exhaust Manifold Bolt/Stud
First Pass 15 N•m 11 lb ft
Final Pass 30 N•m 22 lb ft
Exhaust Manifold Heat Shield Bolt 9 N•m 80 lb in
Fan and Water Pump Pulley Bolt 25 N•m 18 lb ft
Frame Cross Bar Bolt 100 N•m 74 lb ft
Fuel Meter Body Bracket Bolt 10 N•m 89 lb in
Fuel Pipe Bracket Bolt 6 N•m 53 lb in
Fuel Pipe Retainer Nut 3 N•m 27 lb in
Fuel Supply Pipe Nut (Fuel Tank Side) 30 N•m 22 lb ft
Generator and Drive Belt Tensioner Bracket Bolt to Engine 41 N•m 30 lb ft
Generator and Drive Belt Tensioner Bracket Stud to Engine 20 N•m 15 lb ft

Engine Marine/Industrial 4.3L 6-3
2000 Marine/Industrial
FastenerTightening Specifications (cont’d)
Specification
Application Metric English
Generator and Drive Belt Tensioner Bracket Stud Nut 41 N•m 30 lb ft
Ground Wire Bolt to Rear of Left Side Cylinder Head 16 N•m 12 lb ft
Ground Wire Nut to Rear of Right Side Cylinder Head 16 N•m 12 lb ft
Heater Hose Bracket Bolt to Generator and Drive Belt Tensioner
Bracket 25 N•m 18 lb ft
Ignition Coil Stud 12 N•m 106 lb in
Knock Sensor 20 N•m 15 lb ft
Lower Intake Manifold Stud
First Pass in Sequence 3 N•m 27 lb in
Second Pass in Sequence 12 N•m 106 lb in
Final Pass in Sequence 15 N•m 11 lb ft
Oil Cooler Pipe Bracket to Oil Pan Bolt 12 N•m 106 lb in
Oil Filter Fitting 55 N•m 41 lb ft
Oil Level Indicator Tube Bolt 12 N•m 106 lb in
Oil Pan Baffle Bolt 12 N•m 106 lb in
Oil Pan Bolt and Nut 25 N•m 18 lb ft
Oil Pan Drain Plug 25 N•m 18 lb ft
Oil Pan Skid Plate Bolt 20 N•m 15 lb ft
Oil Pump Bolt to Rear Crankshaft Bearing Cap 90 N•m 66 lb ft
Oil Pump Cover Bolt 12 N•m 106 lb in
Power Steering Pump Bracket Bolt to Engine 41 N•m 30 lb ft
Power Steering Pump Bracket Bolt to Engine 20 N•m 15 lb in
Power Steering Pump Bracket Stud Nut 41 N•m 30 lb ft
Power Steering Pump Bolt 50 N•m 37 lb ft
Power Steering Pump Nut to Engine (Rear Bracket to Engine) 41 N•m 30 lb ft
Power Steering Pump Rear Bracket Nut 50 N•m 37 lb ft
Secondary Air Injection (AIR) Check Valve Pipe Bracket Bolt to
Exhaust Manifold 10 N•m 89 lb in
Secondary Air Injection (AIR) Check Valve Pipe Stud Nut 25 N•m 18 lb ft
Spark Plug
Initial Installation (NEW Cylinder Head) 30 N•m 22 lb ft
All Subsequent Installations 15 N•m 11 lb ft
Spark Plug Wire Support Bolt 12 N•m 106 lb in
Starter Motor Wiring Harness/Transmission Cooler Pipe Bracket to
Oil Pan Bolt 9 N•m 80 lb in
Throttle Body Stud 9 N•m 80 lb in
Transmission to Oil Pan Bolt 47 N•m 35 lb ft
Transmission Cover Bolt 12 N•m 106 lb in
Upper Intake Manifold Stud
First Pass 5 N•m 44 lb in
Final Pass 9 N•m 80 lb in
Valve Lifter Pushrod Guide Bolt 16 N•m 12 lb ft
Valve Rocker Arm Bolt 30 N•m 22 lb ft
Valve Rocker Arm Cover Bolt 12 N•m 106 lb in

6-4 Marine/Industrial 4.3L Engine
2000 Marine/Industrial
FastenerTightening Specifications (cont’d)
Specification
Application Metric English
Water Outlet Stud 25 N•m 18 lb ft
Water Pump Bolt 45 N•m 33 lb ft
Engine Mechanical Specifications
Specification
Application Metric English
General Data
Engine Type V6
Regular Production Option (RPO) Code L35 VIN Code W
Displacement 4.3L 262 CID
Bore 101.60 mm 4.012 in
Stroke 88.39 mm 3.480 in
Compression Ratio 9.2:1
Firing Order 1-6-5-4-3-2
Spark Plug Gap 1.52 mm 0.060 in
42 kPa at 6.0 psig at
1,000 engine rpm 1,000 engine rpm
Oil Pressure (Minimum) at Normal Operating Temperature 125 kPa at 18.0 psig at
2,000 engine rpm 2,000 engine rpm
166 kPa at 24.0 psig at
4,000 engine rpm 4,000 engine rpm
Balance Shaft
Rear Bearing Journal Clearance 0.050-0.088 mm 0.0020-0.0035 in
Rear Bearing Journal Diameter 38.085-38.100 mm 1.4994-1.500 in
Camshaft
End Play 0.0254-0.2286 mm 0.0010-0.0090 in
Journal Diameter 47.440-47.490 mm 1.8677-1.8696 in
Journal Diameter Out-of-Round 0.025 mm (Maximum) 0.0010 in (Maximum)
Lobe Lift (Exhaust) 7.20-7.30 mm 0.283-0.287 in
Lobe Lift (Intake) 6.97-7.07 mm 0.274-0.278 in
Runout 0.065 mm 0.0026 in
Connecting Rod
Connecting Rod Bearing Clearance (Production) 0.038-0.078 mm 0.0015-0.0031 in
Connecting Rod Bearing Clearance (Service) 0.025-0.063 mm 0.0010-0.0025 in
Connecting Rod Side Clearance 0.15-0.44 mm 0.006-0.017 in
Connecting Rod Journal Diameter 57.116-57.148 mm 2.2487-2.2497 in
Connecting Rod Journal Taper (Production) 0.00508 mm (Maximum) 0.00030 in (Maximum)
Connecting Rod Journal Taper (Service) 0.025 mm (Maximum) 0.0010 in (Maximum)
Connecting Rod Journal Out-of-Round (Production) 0.007 mm (Maximum) 0.0002 in (Maximum)
Connecting Rod Journal Out-of-Round (Service) 0.025 mm (Maximum) 0.0010 in (Maximum)
Crankshaft
Crankshaft Bearing Clearance (Journal #1-Production) 0.02-0.0508 mm 0.0008-0.0020 in
Crankshaft Bearing Clearance (Journal #2, #3 and #4-Production) 0.028-0.058 mm 0.0011-0.0023 in
Crankshaft Bearing Clearance (Journal #1-Service) 0.0254-0.05 mm 0.0010-0.0020 in
Crankshaft Bearing Clearance (Journal #2, #3 and #4-Service) 0.025-0.063 mm 0.0010-0.0250 in
Crankshaft End Play 0.050-0.20 mm 0.002-0.008 in
Crankshaft Journal Diameter (Journal #1) 62.199-62.217 mm 2.4488-2.4495 in
Crankshaft Journal Diameter (Journal #2 and #3) 62.191-62.215 mm 2.4485-2.4494 in

Engine Marine/Industrial 4.3L 6-5
2000 Marine/Industrial
Engine Mechanical Specifications (cont’d)
Crankshaft Journal Diameter (Journal #4) 62.179-62.203 mm 2.4480-2.4489 in
Crankshaft Journal Out-of-Round (Production) 0.005 mm (Maximum) 0.0002 in (Maximum)
Crankshaft Journal Out-of-Round (Service) 0.025 mm (Maximum) 0.0010 in (Maximum)
Crankshaft Journal Taper (Production) 0.007 mm (Maximum) 0.0003 in (Maximum)
Crankshaft Runout 0.025mm (Maximum) 0.0010 in (Maximum)
Cylinder Bore
Diameter 101.618-101.643 mm 4.0007-4.0017 in
Out-of-Round (Production) 0.0127 mm (Maximum) 0.00050 in (Maximum)
Out-of-Round (Service) 0.05 mm (Maximum) 0.002 in (Maximum)
Taper (Production Relief Side) 0.025 mm (Maximum) 0.0010 in (Maximum)
Taper (Production Thrust Side) 0.012 mm (Maximum) 0.0005 in (Maximum)
Taper (Service) 0.025 mm (Maximum) 0.0010 in (Maximum)
Cylinder Head
Surface Flatness 0.10 mm (Maximum) 0.004 in (Maximum)
Exhaust Manifold
Surface Flatness (Flange to Flange) 0.25 mm (Maximum) 0.010 in (Maximum)
Surface Flatness (Individual Flange) 0.05 mm (Maximum) 0.002 in (Maximum)
Intake Manifold
Surface Flatness 0.10 mm (Maximum) 0.004 in (Maximum)
Oil Pan
Oil Pan Alignment at Rear of Engine Block 0.3 mm (Maximum) 0.011 in (Maximum)
Piston
Piston Bore Clearance (Production) 0.018-0.061 mm 0.0007-0.0024 in
Piston Bore Clearance (Service) 0.075 mm (Maximum) 0.0029 in (Maximum)
Piston Pin
Clearance in Piston (Production) 0.013-0.023 mm 0.0005-0.0009 in
Clearance in Piston (Service) 0.025 mm (Maximum) 0.010 in (Maximum)
Diameter 23.545-23.548 mm 0.9270-0.9271 in
Fit in Connecting Rod 0.021-0.040 mm 0.0008-0.0016 in
(Interference) (Interference)
Piston Rings (End Gap Measured in Cylinder Bore)
Piston Compression Ring Gap (Production-Top Groove) 0.25-0.40 mm 0.010-0.016 in
Piston Compression Ring Gap (Production- 2nd Groove) 0.46-0.66 mm 0.018-0.026 in
Piston Compression Ring Gap (Service -Top Groove) 0.5 mm (Maximum) 0.19 in (Maximum)
Piston Compression Ring Gap (Service - 2nd Groove) 0.8 mm (Maximum) 0.31 in (Maximum)
Piston Compression Ring Groove Clearance (Production-Top Groove) 0.030-0.070 mm 0.0012-0.0027 in
Piston Compression Ring Groove Clearance (Production- 2nd Groove) 0.040-0.080 mm 0.0015-0.0031 in
Piston Compression Ring Groove Clearance (Service) 0.085 mm (Maximum) 0.0033 in (Maximum)
Piston Oil Ring Gap (Production) 0.25-0.76 mm 0.010-0.029 in
Piston Oil Ring Gap (Service) 0.90 mm(Maximum) 0.035 in (Maximum)
Piston Oil Ring Groove Clearance (Production)0.046-0.096 mm 0.0018-0.00037 in
Piston Oil Ring Groove Clearance (Service) 0.10 mm (Maximum) 0.0039 in (Maximum)
Valve System
Valve Face Angle 45 Degrees
Valve Head Edge Margin 0.79 mm (Minimum) 0.031 in (Minimum)
Valve Lash Net Lash - No Adjustment
Valve Lift (Exhaust) 10.879 mm 0.4280 in
Valve Lift (Intake) 10.527 mm 0.4140 in
Valve Lifter Hydraulic Roller Type
Valve Rocker Arm Roller Pivot Type
Valve Rocker Arm Ratio 1.5:1
Valve Seat Angle 46 Degrees
Valve Seat Runout 0.05 mm (Maximum) 0.002 in (Maximum)
Valve Seat Width (Exhaust) 1.651-2.489 mm 0.065-0.098 in

6-6 Marine/Industrial 4.3L Engine
2000 Marine/Industrial
Engine Mechanical Specifications (cont’d)
Valve Seat Width (Intake) 1.016-1.651 mm 0.040-0.065 in
Valve Spring Free Length 51.3 mm 2.02 in
Valve Spring Installed Height (Exhaust) 42.92-43.43 mm 1.670-1.700 in
Valve Spring Installed Height (Intake) 42.92-43.43 mm 1.670-1.700 in
Valve Spring Pressure (Closed) 338-374 N at 43.2 mm 76-84 lb at 1.70 in
Valve Spring Pressure (Open) 832-903 N at 32.3 mm 187-203 lb at 1.27 in
Valve Stem Clearance (Exhaust-Production) 0.025-0.069 mm 0.0010-0.0027 in
Valve Stem Clearance (Exhaust-Service) 0.025-0.094 mm 0.0010-0.0037 in
Valve Stem Clearance (Intake-Production) 0.025-0.069 mm 0.0010-0.0027 in
Valve Stem Clearance (Intake-Service) 0.025-0.094 mm 0.0010-0.0037 in
Valve Stem Oil Seal Installed Height (Measured from the Top of the
Large Diameter Valve Guide Bevel to the Bottom of the Valve Stem 1-2 mm 0.03937-0.07874 in
Oil Seal)
GM SPO Group Numbers
Application GM SPO Group Number
Accelerator Control Cable Bracket 3.454
Balance Shaft 0.659
Balance Shaft Bearing Kit (Rear) 0.659
Balance Shaft Gear Kit (Includes Drive and Driven Gears) 0.529
Balance Shaft Retainer 0.659
Belt Idler Pulley (Grooved) 1.062
Belt Idler Pulley (Smooth) 1.062
Camshaft Bearing 0.539
Camshaft Retainer 0.529
Camshaft Sprocket 0.736
Camshaft Timing Chain 0.724
Clutch Pilot Bearing 0.649
Connecting Rod 0.603
Connecting Rod Bearing Kit 0.616
Coolant Radiator 1.219
Crankshaft Balancer 0.659
Crankshaft Balancer Key 0.662
Crankshaft Bearing Kit 0.096
Crankshaft Front Oil Seal 0.213
Crankshaft Rear Oil Seal 0.137
Crankshaft Rear Oil Seal Housing 0.137
Crankshaft Rear Oil Seal Housing Retainer Stud 0.137
Crankshaft Rear Oil Seal Retainer Stud 0.137
Crankshaft Position Sensor 2.383
Crankshaft Position Sensor Reluctor Ring 2.383
Crankshaft Position Sensor Seal (O-ring) 2.383
Crankshaft Pulley 0.659
Crankshaft Sprocket 0.728
Cylinder Head 0.269
Cylinder Head Gasket 0.289
Distributor 2.361
Distributor Clamp 2.363
Distributor Gasket 2.363
Dowel Pin (Cylinder Head Locator) 8.939
Dowel Straight Pin (Transmission Locator) 8.939

Engine Marine/Industrial 4.3L 6-7
2000 Marine/Industrial
GM SPO Group Numbers (cont’d)
Application GM SPO Group Number
Drive Belt Tensioner 1.060
EGR Valve 3.670
EGR Valve Gasket 3.680
EGR Valve Inlet Pipe 3.675
Evaporative Emission Canister Purge Solenoid Valve 3.130
Evaporative Emission Canister Purge Solenoid Valve Harness 3.145
Engine Block N.S.
Engine Block Core Hole Plug 0.034
Engine Block Oil Gallery Plug 1.531
Engine Camshaft 0.519
Engine Coolant Heater 1.152
Engine Coolant Temperature Sensor 1.150
Engine Coolant Temperature Gauge Sensor 1.150
Engine Coolant Thermostat 1.246
Engine Crankshaft 0.646
Engine Flywheel 0.666
Engine Front Cover 0.206
Engine Mount 0.029
Engine Mount Bracket 0.029
Engine Oil Level Sensor 1.516
Engine Oil Pressure Gauge Sensor 1.800
Engine Oil Pressure Gauge Sensor Fitting 1.800
Engine Piston Kit (Piston and Pin) 0.629
Engine Wiring Harness Bracket 2.559
Exhaust Manifold 3.601
Exhaust Manifold Gasket 3.270
Exhaust Manifold Heat Shield 3.602
Exhaust Valve 0.297
Expansion Cup Plug (Balance Shaft Rear Bearing Hole) 8.970
Expansion Cup Plug (Camshaft Rear Bearing Hole) 8.970
Fan & Water Pump & A/C Compressor & Generator & Power Steering Pump Belt 1.066
Fan & Water Pump & Generator & Power Steering Pump Belt 1.066
Fan & Water Pump Pulley 1.062
Flywheel Locator Pin 0.669
Front Groove Pin (Crankshaft Balancer) 8.940
Fuel Pipe (Included in Fuel Injection Feed and Return Pipe Kit Only) 3.163
Fuel Pipe Retainer Bracket (Included in Fuel Injection Feed and Return Pipe Kit Only) 3.163
Fuel Injector (O-ring) Seal Kit 3.331
Generator & Drive Belt Tensioner Bracket 1.060
Ignition Coil 2.170
Ignition Coil Wire Harness 2.240
Intake Valve 0.296
Knock Sensor 2.383
Lower Intake Manifold (Included in Lower Intake Manifold Kit Only) 3.265
Lower Intake Manifold Gasket Kit 3.270
MAP Sensor 3.682
MAP Sensor Seal 3.682
Oil Fill Cap 1.758
Oil Fill Tube 1.745
Oil Fill Tube (Lower Bracket) 1.750
Oil Filter 1.836
Oil Filter Bypass Valve 1.837
Oil Filter Fitting 1.855

6-8 Marine/Industrial 4.3L Engine
2000 Marine/Industrial
Application GM SPO Group Number
Oil Level Indicator 1.516
Oil Level Indicator Tube 1.516
Oil Pan 1.426
Oil Pan Drain Plug 1.453
Oil Pan Drain Plug Seal (O-ring) 1.456
Oil Pan Gasket 1.429
Oil Pump 1.652
Oil Pump Cover 1.723
Oil Pump Drive Shaft 1.639
Oil Pump Drive Shaft Retainer 1.639
Oil Pump Pressure Relief Valve 1.609
Oil Pump Pressure Relief Valve Spring 1.609
Oil Pump Pressure Relief Valve Spring Bore Plug 1.609
Oil Pump Pressure Relief Valve Spring Straight Pin 1.609
Oil Pump Screen 1.656
PCV Tube 1.762
PCV Valve 1.745
PCV Valve Cover 1.745
PCV Valve Elbow 1.762
PCV Valve Hose 1.762
Pin (Oil Pump Locator) 1.723
Piston Ring Kit 0.643
Power Steering Pump Bracket 6.606
Secondary Air Injection (AIR) Check Valve 3.670
Secondary Air Injection (AIR) Check Valve Gasket 3.680
Secondary Air Injection (AIR) Check Valve (Crossover) Pipe 3.675
Secondary Air Injection (AIR) Check Valve Pipe 3.675
Spark Plug 2.270
Spark Plug Wire 2.240
Spark Plug Wire Shield 2.251
Spark Plug Wire Support 2.251
Spring Type S Pin (Crankshaft Rear Oil Seal Housing Locator) 8.940
Starter Motor 2.041
TBI Fuel Meter 3.734
Throttle Body 3.335
Throttle Body to Upper Manifold Gasket (Included in Service Kits Only) N.S.
Torque Converter Housing Access Hole Plug (Rubber/at Oil Pan) 4.104
Transmission Brace 4.081
Transmission Cover 4.105
Upper Intake Manifold (Included in Upper Intake Manifold Kit Only) 3.625
Upper Intake Manifold to Lower Intake Manifold Gasket (Included in Intake Manifold Seal Kit) 3.270
Valve Lifter 0.459
Valve Lifter Pushrod Guide 0.439
Valve Pushrod 0.426
Valve Rocker Arm Assembly 0.333
Valve Rocker Arm Cover 0.386
Valve Rocker Arm Cover Bolt Grommet 0.423
Valve Rocker Arm Cover Gasket 0.423
Valve Rocker Arm Support 0.429
Valve Spring 0.303
Valve Spring Cap 0.309
Valve Stem Key 0.310
Valve Stem Oil Seals 0.308
GM SPO Group Numbers (cont’d)

Engine Marine/Industrial 4.3L 6-9
2000 Marine/Industrial
Application GM SPO Group Number
Water Outlet 1.153
Water Pump Gaskets 1.079
Water Pump Inlet Hose 1.097
GM SPO Group Numbers (cont’d)
Water Pump Kit (with Gaskets) 1.069
Application Type of Material GM Part Number
Balancer Shaft Driven Gear Bolt Threadlock 12345382
Camshaft Retainer Bolt Threadlock 12345382
Crankshaft Balancer Keyway Adhesive 12346141
Cylinder Head Bolt Sealant 12346004
Engine Block to the Crankshaft Rear Oil Seal Housing
Junction at the Oil Pan Sealing Surfaces Adhesive 12346141
Engine Block to the Engine Front Cover Junction at the Oil
Pan Sealing Surfaces Adhesive 12346141
Engine Block at the Lower Intake Manifold Sealing Surfaces Adhesive 12346141
Engine Block Coolant Drain Hole Plug Sealant 12346004
Engine Block Core Hole Plug Threadlock 12345382
Engine Block Oil Gallery Plug Sealant 12346004
Engine Coolant Temperature (ECT) Sensor Sealant 12346004
Engine Coolant Temperature (ECT) Gauge Sensor Sealant 12346004
Engine Oil SAE 5W-30 Oil 12345610
Engine Oil Pressure Sensor Sealant 12346004
Engine Oil Pressure Sensor Fitting Sealant 12346004
Engine Oil Supplement Lubricant 1052367
Evaporative Emission (EVAP) Canister Purge Solenoid Valve Stud Threadlock 12345382
Exhaust Manifold Bolt/Stud Threadlock 12345382
Expansion Cup Plug (Balance Shaft Rear Bearing Hole) Sealant 12346004
Expansion Cup Plug (Camshaft Rear Bearing Hole) Sealant 12346004
Fuel Meter Body Bracket Bolt Threadlock 12345382
Fuel Pipe Bolt Threadlock 12345382
Lower Intake Manifold Bolt Threadlock 12345382
Oil Level Indicator Tube Sealant 12346004
Oil Pump Screen Tube Sealant 12346004
Throttle Body Stud Threadlock 12345382
Upper Intake Manifold Stud Threadlock 12345382
Valve Train Component Prelube Lubricant 12345501
Water Pump Bolt Sealant 12346004
Sealers, Adhesives and Lubricants

6-10 Marine/Industrial 4.3L Engine
2000 Marine/Industrial
Checks Action
Engine Performance diagnosis procedures are covered in Engine Controls and should be consulted for diagnosis of any
Drivability, Emissions or Malfunctioning Indicator Lamp (MIL) concerns.
The following diagnosis covers common concerns and possible causes.
When the proper diagnosis is made, the concern should be corrected by adjustment, repair or replacement as required.
Refer to the appropriate section of the service manual for each specific procedure.
This diagnostic table will assist in engine misfire diagnosis due to a mechanical concern such as a faulty engine camshaft,
worn or damaged bearings or bent valve pushrod.
Thsi table will not isolate a crossed fuel injector wire, faulty fuel injector or any other drivability component failure that may
cause a misfire.
The Powertrain On-Board Diagnostic System checks must be performed first.
When using this table to make a Base Engine Misfire diagnosis, begin with the preliminary information below and then
proceed to the specific category.
Preliminary 1. Perform DTC P0300 before proceeding with Base Engine Misfire Diagnosis
information.
DTC P0300 will assist in determining which cylinder or cylinders are misfiring.
2. Perform a visual inspection of the following:
A loose or improperly isnstalled engine flywheel or crankshaft balancer
Worn, damaged or misaligned accessory drive system components
3. Listen to the engine for any abnormal internal engine noises.
4. Inspect the engine for acceptable oil pressure.
5. Verify if the engine has excessive oil consumption.
6. Verify if the engine has excessive coolant consumption.
7. Perform a compression test on the engine.
Intake Manifold Leaks An intake manifold that has a vacuum leak may cause a misfire.
Inspect for the following:
Improperly installed or damaged vacuum hoses
Faulty or improperly installed lower intake manifold and/or gaskets
Cracked or damaged lower intake manifold
Improperly installed MAP sensor
The sealing grommet of the MAP sensor should not be torn or damaged
Improperly installed throttle body or damaged gasket
Warped intake manifold
Warped or damaged cylinder head sealing surface
Coolant Consumption Coolant consumption may or may not cause the engine to overheat.
Inspect for the following:
External coolant leaks
Faulty cylinder head gasket
Warped cylinder head
Cracked cylinder head
Damaged engine block
Oil Consumption Oil consumption may or may not cause the engine to misfire.
1. Remove the spark plugs and inspect for an oil fouled spark plug.
2. Perform a cylinder compression test.
3. If the compression test indicates worn valves or valve guides, inspect the following:
Worn, brittle or improperly installed valve stem oil seals
Worn valve guides
Worn valve stems
Worn or burnt valves or valve seats
4. If the compression test indicates worn or damaged piston rings, inspect the following:
Broken or improperly seated piston rings
Excessive piston ring end gap
Excessive cylinder bore wear or taper
Cylinder damage
Piston damage
Diagnostic Information and Procedures
Base Engine Misfire Diagnosis