Ok tomarrow Im having a compression check done on my car due to the fact that I keep getting a mis fire on cylinder #5. I am trying to rule out a bad piston ring and hoping its just a bad valve seal or head gasket as to why I am getting oil on the threads of my spark plug. I have done every thing to rule out the electrical system being bad. Now what can I do to tell that the mechanics arent trying to pull one over on me. What is the normal compression so that when they do the test I can tell what they are saying is the truth. Its the whole concept of if its not broke dont fix it. Please help.
hi, you may want to check compression on all 8 pistons,then compare the results.25 psi or more difference indicates a problem-bad valves,headgasket maybe?.if something is broken,most likely you will find a reading of 0 psi in one of them.good luck!
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