Post by Stinger on Nov 10, 2008 1:55:18 GMT -5
Q: I think I may have blown the headgasket. How do I check for sure?
A: You need to do a compression test. All cylinders should be between 10% of each other. Follow the procedure below:
Compression Test
Ideally, you should bring the engine up to full operating temperature before proceeding, the test can be done cold though, it's just a bit less accurate.
1. First, take an air compressor or shop vac and clean the area around each spark plug recess BEFORE removing the plugs in order to prevent any dirt/sand from dropping into the cylinder.
2. If turbocharged, remove the intercooler. Be sure to cover the turbo inlet hole with a towel or cup.
3. Number each spark plug wire with clothes pins or tape and a pen so you can return them to the proper location when reinstalling them.
4. Remove the spark plug wires. You should twist them while removing them to try to break them lose before yanking on them. Try to pull on the rubber boots, not the wire itself.
5. Remove all of the spark plugs. Use the kind of compression gauge that screws into the spark plug holes for best results.
6. Install the Compression tester into the first spark plug hole and then crank the engine over with the starter and allow enough time for the gauge to hold at a given pressure (probably 4-6 compression strokes). Repeat this process twice for each cylinder. Record the results for each cylinder for comparison after completion. If you don't have a compression tester, you can rent one from Autozone.
7. Ideal results would give you 120-150psi in each cylinder for a turbo motor and 140-170 for a N/A engine. If your lowest psi is more than 10% lower than the highest psi (140 and 95 for example) then you have a problem.
8. After you have tested all cylinders, reinstall the plugs and wires in the proper order.
A: You need to do a compression test. All cylinders should be between 10% of each other. Follow the procedure below:
Compression Test
Ideally, you should bring the engine up to full operating temperature before proceeding, the test can be done cold though, it's just a bit less accurate.
1. First, take an air compressor or shop vac and clean the area around each spark plug recess BEFORE removing the plugs in order to prevent any dirt/sand from dropping into the cylinder.
2. If turbocharged, remove the intercooler. Be sure to cover the turbo inlet hole with a towel or cup.
3. Number each spark plug wire with clothes pins or tape and a pen so you can return them to the proper location when reinstalling them.
4. Remove the spark plug wires. You should twist them while removing them to try to break them lose before yanking on them. Try to pull on the rubber boots, not the wire itself.
5. Remove all of the spark plugs. Use the kind of compression gauge that screws into the spark plug holes for best results.
6. Install the Compression tester into the first spark plug hole and then crank the engine over with the starter and allow enough time for the gauge to hold at a given pressure (probably 4-6 compression strokes). Repeat this process twice for each cylinder. Record the results for each cylinder for comparison after completion. If you don't have a compression tester, you can rent one from Autozone.
7. Ideal results would give you 120-150psi in each cylinder for a turbo motor and 140-170 for a N/A engine. If your lowest psi is more than 10% lower than the highest psi (140 and 95 for example) then you have a problem.
8. After you have tested all cylinders, reinstall the plugs and wires in the proper order.