Correct EJ255 compression ??

[Sammy C]

Hi guys my 06 Forester STi is using ALOT of oil - about 3 litres in 1500 miles. I decided to have the compression tested to see if I had any worn piston rings which would answer the oil consumption question. I've just got the results.... 115,114,113,117psi. The guy said these are the most consistent results he's seen in a long while but I'm not sure if these are correct or by some coincedense these are all equally low...anyone got any idea as what these are supposed to be for an import?? Or any ideas as to where all my oil is going! Cheers guys

[Gambit]

I couldn't tell you mate maybe Martin on here might know could PM HERE

Or Tlag Bips might also know they build and repair Subaru Engines too down in Coventry ;) 

[Tlag]

Those numbers sound ok. The fact that they are so similar means the rings and pistons are in good shape.

You are however losing a lot of oil. Take a look under the car at the bottom of the engine and gearbox.

My bet is that you will find the underside covered in oil. If the underside of the sump is covered, I would suggest the front crank seal. If the sump is dry, I would suspect the rear crank seal.

If the underside is totally dry of oil, it may be a rocker cover gasket ( although they normally just weep and wouldn't leak that much oil in that time scale.

[Gambit]

Cheers Tlag I wasn't sure for some reason I thought they came as 10.7.5 and so on :)

[Sammy C]

Hi guys thanks so much for replying! The guy who did the compression test suggested using a slightly thicker oil as it may still be getting past the rings. There's no leaks at all coming from the underside of the car and the engine bay is dry too. I thought it may be that the turbo has a hairline crack or something??? Although i had it on the dyno last month and it held 1.2bar as it should so I'm really not sure. Could the turbo be leaking but still holding good boost??

 

Thanks, sam.

[Jay762]

Do you have any blue smoke coming out of the exhaust? If the oil is getting past your rings or there is an issue with the turbo you will get blue smoke how many miles has the car done?

 

as long as the turbines are supported you will get pressure on spool up.

 

3 litres in 1500  miles is a lot, if it is coming past the rings your plugs could be fouled - what colour are they?

 

Is the coolant fluid clear, no milkiness? Might be worth doing a sniff test just to make sure in order to check head gasket??

[Tlag]

Those three items:

Burning it = blue smoke,

Dropping it = oil on the floor under the car and/or car wet with oil

Head gaskets= milky, mayonnaise type stuff in the oil filler neck, and oily film in the coolant,

Are about all that can happen to oil to make it disappear.

Have you got tinted rear windows, would you notice blue smoke over ordinary coloured smoke?

[Ash007ks]

Rockers are common and Cam seals.

 

but maybe its your turbo thats burning a little, mine only used to do it when thrashed or idle.