This sticky is for links to the most asked about questions, info, specs and general knowledge of the Vortec 4.2L I-6.
If you see a thread that should be considered to be added here, click on the <Report> button with a note indicating that it should be added.
General
Vortec 4200 Wiki (external site)
Video: Atlas engine teardown
I6 underhood service specifications
"The GM Vortec LL8 Links and Specs Library"
How-To: Power Steering Pump Replacement
Motor Mount Replacement Issues
'06 4.2 swap into an '05
2002 Bravada/Envoy/Trailblazer muffler DIY replacement
No Crank, Like Attempting To Start In Drive
huge problem after PCM update / calibration (PCM Security Relearn)
How to replace motor mounts painlessly
Trailblazer oil pressure gauge doesn't tell you the oil pressure (4.2L engines) (YouTube)
Where to connect a real pressure gauge
Cranks but won't start
4.2L interchangeability by years
4.2L Incompatibility by years ('04 engine in '08 truck, no start)
2002 Envoy A/C delete belt
No Start, Multiple U1000 codes, Class 2 Serial Communication Problem
SOLVED!-04 Trailblazer LT 4.2 L no crank - no start
Good rundown of differences in LL8 through the years (Video)
Vibrations while idling/stopped
4.2L P10 PCM pinout
Very slight miss/misfire at idle
Using ACDelco Top Engine Cleaner
Carbon cleaning the 4.2L
Using TEC
Questions and using TEC
Cooling
Fan Clutch 101 (Link to TrailVoy post)
How to test the electro-viscous fan clutch
Best brand for new thermostat
Tips on 1st Thermostat replacement on Inline-6
Alternator and Thermostat Replacement (How-to)
How to Change a Thermostat on a Trailblazer / Envoy
How to replace the water pump
Reason for fan at startup?(Fan roar on startup)
Using chain for fan clutch removal
Fan clutch frozen to water pump (How to remove)
Tips on 1st Thermostat replacement on Inline-6
Radiator Replacement
Fan speed command chart
EV Fan Operation
EV Fan Clutch Recommendations for proper operation
Heater quick disconnect part numbers
Overheating issues and fan clutch brand comparisons
Coolant Types (Dexcool vs. ???)
Aluminum replacement radiator (Amazon)
Engine Mechanical
How to replace I6 timing chain and tensioner
Remove the intake manifold and valve cover
Remove the oil pan
How-to: Replace the Cam Phaser (aka: VVT Actuator)
How To: Clean The Camshaft Position Actuator Solenoid (CPAS) Picture Heavy
Engine oil in spark plug pockets
Replacing 1st gen damper/seal with 2nd gen
Oil Filter Options
More Oil Filter Options
4.2L LL8 Harmonic Balancer Removal/Installation
P1345 - Crankshaft Angle Correlation Fault
How to remove head bolts without breaking (Video)
Exhaust Manifold Bolts
Cylinder head gasket discrepancy
Dorman Cam Phaser
4.2L Head Removal/Engine restoration (and why not to do it/failure)
If you see a thread that should be considered to be added here, click on the <Report> button with a note indicating that it should be added.
General
Vortec 4200 Wiki (external site)
Video: Atlas engine teardown
I6 underhood service specifications
"The GM Vortec LL8 Links and Specs Library"
How-To: Power Steering Pump Replacement
Motor Mount Replacement Issues
'06 4.2 swap into an '05
2002 Bravada/Envoy/Trailblazer muffler DIY replacement
No Crank, Like Attempting To Start In Drive
huge problem after PCM update / calibration (PCM Security Relearn)
How to replace motor mounts painlessly
Trailblazer oil pressure gauge doesn't tell you the oil pressure (4.2L engines) (YouTube)
Where to connect a real pressure gauge
Cranks but won't start
4.2L interchangeability by years
4.2L Incompatibility by years ('04 engine in '08 truck, no start)
2002 Envoy A/C delete belt
No Start, Multiple U1000 codes, Class 2 Serial Communication Problem
SOLVED!-04 Trailblazer LT 4.2 L no crank - no start
Good rundown of differences in LL8 through the years (Video)
Vibrations while idling/stopped
4.2L P10 PCM pinout
Very slight miss/misfire at idle
Using ACDelco Top Engine Cleaner
Carbon cleaning the 4.2L
Using TEC
Questions and using TEC
Cooling
Fan Clutch 101 (Link to TrailVoy post)
How to test the electro-viscous fan clutch
Best brand for new thermostat
Tips on 1st Thermostat replacement on Inline-6
Alternator and Thermostat Replacement (How-to)
How to Change a Thermostat on a Trailblazer / Envoy
How to replace the water pump
Reason for fan at startup?(Fan roar on startup)
Using chain for fan clutch removal
Fan clutch frozen to water pump (How to remove)
Tips on 1st Thermostat replacement on Inline-6
Radiator Replacement
Fan speed command chart
EV Fan Operation
EV Fan Clutch Recommendations for proper operation
Heater quick disconnect part numbers
Overheating issues and fan clutch brand comparisons
Coolant Types (Dexcool vs. ???)
Aluminum replacement radiator (Amazon)
Engine Mechanical
How to replace I6 timing chain and tensioner
Remove the intake manifold and valve cover
Remove the oil pan
How-to: Replace the Cam Phaser (aka: VVT Actuator)
How To: Clean The Camshaft Position Actuator Solenoid (CPAS) Picture Heavy
Engine oil in spark plug pockets
Replacing 1st gen damper/seal with 2nd gen
Oil Filter Options
More Oil Filter Options
4.2L LL8 Harmonic Balancer Removal/Installation
P1345 - Crankshaft Angle Correlation Fault
How to remove head bolts without breaking (Video)
Exhaust Manifold Bolts
Cylinder head gasket discrepancy
Dorman Cam Phaser
4.2L Head Removal/Engine restoration (and why not to do it/failure)
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