Oil on the plugs and low comps usually mean broken rings or a hole in the piston, get a leak down test done this will help pin point the problem.

Answered by mhpautos (expert)
26,898 answers provided

What is a leak down test

Response from kennethmorrow
2 questions asked

This is when you apply a low pressure compressed air into the cylinder at TDC with both valves closed, there is a special tool that screws into the spark plug hole, with the low pressure applied you can determine where the leaks are, such as valves, rings etc.

Answered by mhpautos (expert)
26,898 answers provided

Can I do the leak down test myself or do I hav to take it to a shop

Response from kennethmorrow
2 questions asked

you need the adaptor a compressor and a regulator to drop the air pressure down, to high a pressure will force the piston down and open a valve this will give you a false reading, if a manual transmission you can put it in gear and pull the hand brake on to help hold the engine at TDC.

Answered by mhpautos (expert)
26,898 answers provided