Compression test results

[skinnyman9000 0]

My car stinks of oil, and it burns alot out through the exhaust, which caused it to fail its MOT. So whilst having some other work done on it i had the garage conduct a compression test. Results are, its fine, which removes my initial thought of worn valve seals.

 

So if the valve seals are fine, and the compression is fine, what can be causing the excessive oil burn?

 

Cheers

 

Chris.

[Toad 0]

The valve stem seals shouldn't affect the compression test very much as the valves are closed when the engine comes up to compression. Chances are, it is the stem seals still.

[steve @ 0]

Yeah was about to say. Most probably your valve stem seals. For the time being could try running a thicker oil 10w50, 15w40, 15w50 etc to minimise the situation.

[Kevin Bacon 5]

The valve stem seals shouldn't affect the compression test very much as the valves are closed when the engine comes up to compression. Chances are, it is the stem seals still.

 

Spot on.

 

He might have a broken oil control ring though, which wouldn't affect compression.... A leakdown test is the only thorough way to check really....

[Critical_Mass 10]

He might have a broken oil control ring though, which wouldn't affect compression.... A leakdown test is the only thorough way to check really....

 

cheesewire, Is the oil control ring the bottom one around the piston (sorry if dumb Q)?

 

I have exactly the same problem with my VR. Im currently using 15w40 oil instead of 10w40. It has brought oil consumption down a bit.

 

How is a leakdown test carried out?

 

I know the plugs will get oiled up thus will reduce effectiveness and also the performance of the engine will drop. But if new spark plugs were fitted, would the performance still be lack due to the oil/fuel mixture being burnt within the cylinders?