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HOMESERVICE MANUALSCHEVROLET2006COBALT SS, 4D SEDAN, STANDARDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 500 (ENGINE MECHANICAL - 3.9L)SPECIFICATIONSENGINE MECHANICAL SPECIFICATIONS
2006 Chevrolet Cobalt SS, 4D Sedan, Standard

Engine Mechanical Specifications

2006 Chevrolet Cobalt SS, 4D Sedan, StandardSECTION Engine Mechanical Specifications
WARNING: This page is about a different car, the 2007 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.
Engine Mechanical Specifications

Application Specification
Metric English
General Data
  • Engine Type
 60 degree V-6
  • Displacement
 3.9L 238 cu. in.
  • RPO
 LZ8
  • VIN
 1
  • Bore
 99 mm 3.90 in
  • Stroke
 84 mm 3.31 in
  • Compression Ratio
 9.8:1
  • Firing Order
 123456
  • Spark Plug Gap
 1.00 mm 0.040 in
Block
  • Camshaft Bearing Bore Diameter - Front and Rear
 55.26-55.31 mm 2.175-2.177 in
  • Camshaft Bearing Bore Diameter - Middle #2, #3
 54.75-54.80 mm 2.155-2.157 in
  • Crankshaft Main Bearing Bore Diameter
 72.1535-72.0695 mm 2.840-2.841 in
  • Crankshaft Main Bearing Bore Out-of-Round
 0.008 mm 0.00031 in
  • Cylinder Bore Diameter
 99.000-99.018 mm 3.897-3.898 in
  • Cylinder Bore Out-of-Round - Diameter - Production
 0.026 mm 0.0010 in
  • Cylinder Bore Out-of-Round - Diameter - Service
 0.030 mm 0.0011 in
  • Cylinder Bore Taper - Production
 0.026 mm 0.0010 in
  • Cylinder Bore Taper - Service
 0.030 mm 0.0011 in
  • Cylinder Head Deck Height
 224 mm 8.818 in
  • Cylinder Head Deck Surface Flatness
 0.05 mm per 150 mm 0.0019 in per 5.905 in
  • Valve Lifter Bore Diameter
 21.417-21.455 mm 0.843-0.844 in
Camshaft
  • Camshaft Bearing Inside Diameter
 51.500-51.525 mm 2.028-2.029 in
  • Camshaft Journal Diameter
 51.415-51.440 mm 2.024-2.025 in
  • Camshaft Journal Out-of-Round
 0.025 mm 0.001 in
  • Camshaft Lobe Lift - Exhaust
 6.9263 mm 0.2727 in
  • Camshaft Lobe Lift - Intake
 6.9263 mm 0.2727 in
Cooling System
  • Thermostat Full Open Temperature
 195 degrees
Connecting Rod
  • Connecting Rod Bearing Clearance
 0.018-0.062 mm 0.0007-0.0024 in
  • Connecting Rod Bore Diameter
 60.322-60.338 mm 2.375-2.376 in
  • Connecting Rod Bore Out-of-Round
 0.006 mm 0.00023 in
  • Connecting Rod Length - Center to Center
 150 mm 5.9 in
  • Connecting Rod Side Clearance
 0.200-0.241 mm 0.008-0.009 in
Crankshaft
  • Connecting Rod Journal Diameter
 57.122-57.138 mm 2.248-2.249 in
  • Connecting Rod Journal Out-of-Round
 0.005 mm 0.0002 in
  • Connecting Rod Journal Taper
 0.005 mm 0.0002 in
  • Connecting Rod Journal Width
 21.92-22.08 mm 0.863-0.869 in
  • Crankshaft End Play
 0.060-0.210 mm 0.0024-0.0083 in
  • Crankshaft Main Bearing Clearance - Except #3
 0.019-0.064 mm 0.0008-0.0025 in
  • Crankshaft Main Bearing Clearance - #3 Thrust Bearing
 0.032-0.077 mm 0.0012-0.0030 in
  • Crankshaft Main Journal Out-of-Round
 0.005 mm 0.0002 in
  • Crankshaft Main Journal Taper
 0.005 mm 0.0002 in
  • Crankshaft Rear Flange Runout
 0.04 mm 0.0016 in
Cylinder Head
  • Combustion Chamber Depth - at Measurement Point
 2.2 mm 0.087 in
  • Surface Finish - Maximum
 2.8 RA
  • Surface Flatness - Block Deck
 0.08 mm per 152 mm 0.003 in per 6 in
  • Surface Flatness - Exhaust Manifold Deck
 0.1 mm 0.004 in
  • Surface Flatness - Intake Manifold Deck
 0.1 mm 0.004 in
  • Valve Guide Bore - Exhaust
 8.01 mm 0.315 in
  • Valve Guide Bore - Intake
 8.01 mm 0.315 in
  • Valve Guide Installed Height
 16.6 mm 0.654 in
Lubrication System
  • Oil Capacity - with Filter
 3.8 liter 4.0 quarts
  • Oil Pressure - @ 1850 RPM
 207-310 kPa 30-45 PSI
  • Oil Pressure - @ Idle with Warm Engine
 185 kPa 26 PSI
Oil Pump
  • Gear Diameter
 38.05-38.10 mm 1.498-1.500 in
  • Gear Pocket - Depth
 30.52-30.58 mm 1.202-1.204 in
  • Gear Pocket - Diameter
 38.176-38.226 mm 1.503-1.505 in
  • Gears Lash
 0.094-0.195 mm 0.0037-0.0077 in
  • Relief Valve-to-Bore Clearance
 0.038-0.089 mm 0.0015-0.0035 in
Pin
  • Piston Pin Clearance to Connecting Rod Bore - Press Fit
 -0.004 to -0.021 mm -0.0001 to -0.0008 in
  • Piston Pin Clearance to Piston Pin Bore
 0.002-0.010 mm 0.00008-0.0004 in
  • Piston Pin Diameter
 23.952-23.955 mm 0.942-0.943 in
  • Piston Pin Length
 64.21-64.44 mm 2.57-2.53 in
Piston
  • Piston Diameter - Production
 98.970-99.008 mm 3.896-3.897 in
  • Piston Diameter - Service Limit
 98.950 mm 3.895 in
  • Piston Pin Bore Diameter
 23.957-23.962 mm 0.943 in
  • Piston Ring Groove Width
 1.22-1.24 mm 0.048-0.049 in
  • Piston to Bore Clearance - Production
 -0.008 to +0.048 mm -0.0003 to +0.0018 in
  • Piston to Bore Clearance - Service Limit - Maximum
 0.080 mm 0.003 in
Piston Ring End Gap
  • First Compression Ring
 0.15-0.30 mm 0.006-0.011 in
  • Second Compression Ring
 0.25-0.45 mm 0.009-0.017 in
  • Oil Control Ring
 0.15-0.65 mm 0.06-0.025 in
Piston Ring to Groove Clearance
  • First Compression Ring
 0.03-0.065 mm 0.001-0.002 in
  • Second Compression Ring
 0.02-0.055 mm 0.0007-0.002 in
  • Oil Control Ring
 0.01 mm 0.004 in
Piston Ring Thickness
  • First Compression Ring
 1.175-1.190 mm 0.046-0.047 in
  • Second Compression Ring
 1.475-1.490 mm 0.058 in
  • Oil Control Ring - Maximum
 2.50 mm 0.098 in
Valves
  • Valve Face Angle
 45 degrees
  • Valve Seat Angle
 46 degrees
  • Valve Seat Depth - Exhaust - From Deck Face
 8.9-9.1 mm 0.350-0.358 in
  • Valve Seat Depth - Intake - From Deck Face
 7.9-8.1 mm 0.311-0.318 in
  • Valve Seat Width - Exhaust
 1.70-2.0 mm 0.067-0.079 in
  • Valve Seat Width - Intake
 1.55-1.80 mm 0.061-0.071 in
  • Valve Stem-to-Guide Clearance
 0.026-0.068 mm 0.0010-0.0027 in
Valve Lifters/Push Rods
  • Push Rod Length - Intake
 146.0 mm 5.75 in
  • Push Rod Length - Exhaust
 152.5 mm 6.0 in
Valve Springs
  • Valve Spring Free Length
 48.5 mm 1.89 in
  • Valve Spring Installed Height
 43.2 mm 1.701 in
  • Valve Spring Load - Closed
 320 N 43.2 mm 75 lb 1.701 in
  • Valve Spring Load - Open
 1036 N 32 mm 230 lb 1.260 in
  • Valve Spring Total Number of Coils
 6.55
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.