A cylinder compression check is a procedure intended to establish the condition of a Camaro’s internal combustion engine. And for an Internal combustion engine to function properly, it must generate adequate compression within the combustion chamber. If a Camaro engine has bad compression pressure, it cannot take advantage of the explosive force created by the expanding gases after ignition—resulting in a loss of horsepower.
The results of a Camaro engine compression test can be utilized to diagnose several engine malfunctions, like a blown head gasket, worn piston rings, or leakage caused by faulty valves. Use this guide when performing an engine compression test.
Compression Test Procedures
- Run the vehicle until the engine reaches normal operating temperatures.
- Make sure the battery is fully charged.
- Clean the recesses around the ignition coils with compressed air.
- Remove the ignition coil packs/coil assemblies from the motor.
- Remove all of the spark plugs from the motor.
- Take off the air intake duct from the throttle body and then secure the throttle in the wide-open position.
- Remove ignition system fuse from the main relay panel, it’s located in the engine compartment.
- Remove the fuel pump relay.
- Insert the compression pressure gauge into the spark plug hole, be careful not to cross-thread the fitting.
- Crank the engine and allow it to rotate for seven revolutions. On the last stroke record the cylinder compression pressure.
- Continue the compression testing procedure for the remaining cylinders, zeroing the gauge for each cylinder.
The compression reading for each cylinder must not be less than 100 psi (690 kPa) for both the 3.6L V6 and the 6.2L V8. And there should not be more than a thirty percent variation between the highest compression reading and the lowest.
Analyzing Compression Test Results
While performing a compression test, if you see the pressure gauge build up quickly, it’s a sign of a health motor. But if the compression pressure is low on the first stroke, and builds gradually for each successive stroke, it’s a good sign of worn piston rings.
If the compression pressure reads low on the first stroke, and doesn’t build with each successive stroke, it’s a sign of a blown head gasket, leaking valves, or even a cracked head.
When analyzing the result of a compression test, the amount of pressure measured is not always as significant as the variation of pressure from cylinder to cylinder.
If two adjacent cylinders have low compression numbers, it’s a good possibility the head gasket is blown between them. If the vehicle has a blown head gasket, engine coolant should be visible in the crankcase or combustion chamber.
If compression pressure is very low or varies significantly between cylinders, perform a leakage test. A leakage test requires a leak-down tester and a high pressure air source for testing (70 psi or 483 kPa minimum). The recommended pressure for a leakage test is 80 psi (or 552 kPa).
Wet Compression Test
Perform a wet compression test on cylinders with low compression. Use a can of fogging oil to spray into the spark plug hole, and around the perimeter of the piston. This will help to temporarily seal the piston rings.
After the oil has been added to the cylinder, perform the compression test again. If the compression rises noticeably during a wet compression test, the piston rings are worn.
If combustion pressure doesn’t rise during the wet compression test, the cylinder is dead. The cylinder and/or piston is worn beyond factory specifications (possibilities include a blown head gasket, scored cylinder walls, damaged piston, or broken piston rings).
After performing a compression check on the Camaro, reinstall all of the parts removed for the test and remove the the object used to prop open the throttle.
|These compression check procedures are specific to the 2010, 2011, 2012, 2013, 2014, 2015 Chevrolet Camaro 3.6L V6 engine, including LLT, LFX models. And 6.2L V8 LS3, L99 and LSA models.|