1999 Volvo S70 Crankcase Pressure Issue

Hi Folks, I am having an issue with my non turbo 1999 Volvo S70's crankcase being pressurized. Oil coming out of the oil cap. Pulling the dipstick, there is smoke coming out of there. Compression is OK on all cylinder. The crankcase vent system is newish (changed about 6 months ago)

I am trying to avoid removing the intake manifold and all to get to the crankcase vent system.

Does anyone have an idea of what else could be causing the pressure? What else could be clogged to cause this pressure issue?

thanks in advance

I don't know the specifics of that engine, but pressure has to be either building up because it's trapped (not venting properly) or because it's building faster than it can be vented (cylinder leakage). I'd do a leakdown test on it and see what that shows; if it's good, then dig into the crankcase venting and see what's what. A smoke test would probably be useful as well.

Yeah, I am not that familiar with Volvo's either. This is my first one. I will do leak down. I should have done that while I was doing the compression test.

Thanks

Are you going on word of mouth that the PCV was done, or did you do it yourself? These are all typical symptoms; someone might have used the crap non-OE parts and it could be failing again, if it was ever done at all...

Pull the intake. Its not hard, other than the front bolt by the power steering pump, but a swivel socket will reach it. The bottom row of bolts don't have to come all the way out, the manifold is slotted.

Something is plugged down there.

When the PCV system was replaced was all of it replaced, oil trap, all hoses, etc.? Sometimes the ports in the block for the oil trap will clog too, so if the ports in the block are plugged up with sludge/carbon, a new or cleaned oil trap won't help.

If you haven't already, remove the flame trap from where the breather elbow attaches to the intake and throw it away. It's not needed, it just causes a choke point for crank case gasses entering the intake, and is prone to clogging.

If it's a turbo either replace or clean the PTC valve.

You probably need a new oil filler cap seal, but don't replace it until you get the pressure issue solved, you don't want to wind up replacing cam seals too.

Replacing the hose from the top of the oil trap on the block to the intake elbow with some 5/8" heater hose is a fairly common upgrade and helps a lot on high mileage engines with a little more blow-by. I've done that to my 850.

Yup, about 6 months ago I did topend rebuild

Did the whole PVC system, but not the flame trap.

I cleaned the ports on the block.

Changed oil filler cap seal last week. This is when things became really noticeable...I suspect, due to the fact the new seal has increase the pressure in the crankcase by "doing what it do" = seal

Compression numbers are a bit low, but are all even at 120psi.

It's almost always the little orifice hole in the plastic air intake line. Start there. Pull it and clear the orifice.

And as long as you're there, ream the rubber line the orifice is in. Sometimes that gets crudded up.

How is the air inlet to the engine ?

May be related to the above post.