V70,2.4T,2001. To high compression on one cylinder. Help!

[Sigmarus]

Hi All!

Im new here. I'got a V70 and have some small problems with this beauty.
Want to change pcv system because i have a smoke from dipstick and make a glow test.

I make a compression test also and the results :
1 cylinder - 12 bar
2 - 15 bar
3 - 13 bar
4 - 12 bar
5- 12 bar

My mechanic said my motor is crap. I cant believe that. I think this compression could be because i have pcv problem or i have spar plugs on oil.
Normally i read a lot of threads with low compression but not to much information about high. Those 15 bar on 2 cylinder are really bad? My motor has a 280kkm run.

Thanks a lot and sorry for my english:)

[abscate]

Dzien Dobry!

That cylinder at 15 bar is very high, the range is 155-180 psi +-30 psi variation

I would pull the spark plug and examine it,if it isn’t full of carbon I would wonder if the test was done correctly

Without lots of carbon, It is hard to get high compression

[oragex]

Not sure but could that be a stuck compression piston ring?

[RickHaleParker]

A stuck ring would produce low compression not high compression.



Excess carbon build up could produce high compression.

Easy way to decarb the cylinders.

• Pull the plugs out
  Pour 1/5 bottle of Seafoam in each cylinder.
  Stuff a rag in each spark plug well.
  Let sit for 24 hours.
  With the rag still in the spark plug wells, crank the engine to push out the Seafoam.
  Remove rags, reinstall plugs.
  Start engine and bump the RPM up to 1500 and hold.

The exhaust may turn black, this is carbon that the Seafoam ate up, it will pass.
It might take 20-30 minutes to clear up but it will.

After the exhaust clears up, take the car out for a drive. Give it some hell to knock out stubborn carbon.

Get it home, let her cool down. Redo the compression test.
With luck, the compression will be back to where it should be.

[oragex]

I would add Sea Foam will work better on a cold engine - winter days are even better: the gap between the piston and ring is slightly increased. You'd also want to find the cause for carbon build up, perhaps a poorly spraying injector/faulty spark plug or ignition coil (just a guess)