Motor is an LS motor with pistons and rods and been running for about a year and a half perfect. Car recently started smoking white smoke and spitting a lil oil out the exhaust and it sounds like a damn WRX. Compression check showed 20 in cylinder 1 and around 180 in 2,3,and 4. Obviously it needs to be torn down to see what exaclty is wrong but what do these simptoms usually mean? Thanks

 

Could be headgasket, piston rings, valve seats. It could mean a host of things depending on your symptoms. Like do you see oil or Antifreeze mixing (that would be headgasket. If you add a little oil to the cylinder that was low and do the compression test again and it goes up dramatically then that could be your rings. It can be many things you just have to make sure the car was warmed up properly b4 the test and that the test was done accurately. ALso do a leakdown test that will tell you if the valves are bad. ALso you can get a vacuum guage which can also identify many issues and is less intrusive. Get the haynes manual or the helms manual. In the haynes manual it will tell you how to read the vacuum guage and the compression tester. It on ly costs $15 so it would be a good investiment. Good luck

 

If compression is that low in one cylinder and it sounds like a WRX, it is most likely a badly broken ring land or melted piston. Pull it apart and find out.

 

If you are able to run a leak down test , you should be able to pin point what is wrong with it before you tear it apart. Basically you listen for the escaping compressed air and depending on where it is coming from will give you your answer. Ive always done these casue its a quick and easy diagnose
Leak down test will tell you alot more than VALVES.....

 

Thanx for the replys guys. Gonna pull it apart soon and find out what exaclty is wrong