Compression test question

[razrman8]

Okay, from what I have read, when doing a compression test you should let the car warm up to operating temperature before performing the test. Then, to proceed with the test, you need to remove the plugs. Now correct me if I am wrong, but if you let the car get up to operating temperature then try to remove the plugs, don't you run the risk of stripping the threads in the head? The heat would soften up the the threads right ? Which runs the risk of thread stripping

 

[92AWDHX40]

I would just be careful ive do it, just be careful and take your time, usually mines not even warmed up i get enough info without warming it up.

 

[1990AWD]

Okay, from what I have read, when doing a compression test you should let the car warm up to operating temperature before performing the test. Then, to proceed with the test, you need to remove the plugs. Now correct me if I am wrong, but if you let the car get up to operating temperature then try to remove the plugs, don't you run the risk of stripping the threads in the head? The heat would soften up the the threads right ? Which runs the risk of thread stripping

How do you strip threads removing something?

Unless you mean the part where the socket grabs, which in that case, just use the right size.

 

[NOSLO2PT0]

You don't worry about that. The engine doesn't get hot enough to melt the aluminum. If that was the case, every engine made would be destroyed upon first startup. It's best to remove the plugs while the engine is warm. But, make sure you tighten the plugs while the engine is COOL. torqueing them down while the engine is hot, will cause excess torque on the plug when it contracts as the engine cools down. This requires a lot more torque to break the plug loose next time, which in turn, could break the plug off. THEN you have some major problems.

 

[92AWDHX40]

Yes i never had problems with doing tests, let it cool and go for it. Simple as that.

 

[razrman8]

Yes i never had problems with doing tests, let it cool and go for it. Simple as that.

Good advice .. Performed the test 180 all the way across ... cylinder 3 took a little bit longer than the other but got there.

 

[kimcheefists]

How do you strip threads removing something?

Unless you mean the part where the socket grabs, which in that case, just use the right size.

You CAN strip out the threads when the engine is hot. Reason being, as any metal warms up, it expands. When the head is hot (expanded) the threads surrounding the spark plug is constricting it. As you loosen the spark plug, you run the risk of removing metal from the head with the spark plug.