S/V/C Crankcase pressure problems

Hey, I'm cross-posting this from VS. Maybe some tbrickers can help me out? Thanks!


1998 V70 awd - 230k miles.

I just replaced the entire PCV system (oil trap, all hoses, cleaned PTC and ports on the block) about 6,000 miles ago. I also replaced the oil cap seal. My problem is that the car still smokes out of the dipstick, and seems to be pushing a lot of oil out of the oil cap seal (like...it's leaking out of the edges of the spark plug cover). The oil cap also isn't quite sucked down onto the valve cover if I unscrew it...it wobbles a little, indicated that there is no vacuum being put on it.

A Volvo technician recommended that I pull the oil pan to clean out the drain in the block/pan for the oil trap. I've never heard of that drain before. He said it runs from the lower breather box port on the block all the way down into the oil pan, and that it is frequently clogged on higher mileage vehicles. Does that sound right?

I should also note that the car has not been compression tested, but I don't have any reason to think the rings are bad. The car has been maintained religiously for it's entire life (I have a HUGE stack of records from when I bought the car).

So, any ideas? I'm getting really frustrated with this, as I don't know what it could be. I really can't afford to keep chasing problems on this car...I put about 600 miles on it per week, and I can't have it breaking down a lot. Thanks in advance for any help!

I agree with the Volvo tech. The bottom of the box has a drain in it to allow the oil that condenses in the PCV box to drain back into the engine. If it is clogged, it will build pressure just like if it was still clogged.

Had the pan off the motor I just installed and damn glad I did. Holy crap what a mucking mess. Drop it and run a brush up that thing. Clean the hell out of it.

According to a bunch of people on VS, I can clean out that drain using a flexible brush from the top (where the breather box is) without dropping the pan.

I'm going to run a compression test on Wednesday and go from there.

Yes you can do that. Spray the piss out of it with Wd-40 or something like that and brush the piss out of it. Then do an oil change. Or, buy an engine flush and do both.

Awesome. That makes me feel better. If the compression is good, then I'm gonna go ahead and re-do the PCV job. Clean the **** outta that lower port, triple-check all the lines, and see where that leaves me. Hopefully with a V70 that runs properly!

it could also be that the tube is broken. My b230ft has the same tube and it hardened over the course of a quarter million miles and broke off and fell into the pan. This caused the tube to not be submerged in the oil in the pan and crank case pressure will go up through this tube and force the dipstick out of its tube and blow oil out of the cap.

If this is the problem, make sure the new tube goes behind the retaining clip or it will get caught in the crank and youll have to pull the pan(which is a pain in the ass).

89TurboBertone said:

it could also be that the tube is broken. My b230ft has the same tube and it hardened over the course of a quarter million miles and broke off and fell into the pan. This caused the tube to not be submerged in the oil in the pan and crank case pressure will go up through this tube and force the dipstick out of its tube and blow oil out of the cap.

If this is the problem, make sure the new tube goes behind the retaining clip or it will get caught in the crank and youll have to pull the pan(which is a pain in the ass).

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I don't think the 2.4 5-cylinder has that tube...does it?

BoostedSwede said:

I don't think the 2.4 5-cylinder has that tube...does it?

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They have the same PCV setup

heres a diagram



#4 is what you are looking for its a small rubber hose about 5/8" in diameter and about 8 inches long

Interesting. Any ideas on what I can shove down there to clean it out?

BoostedSwede said:

Interesting. Any ideas on what I can shove down there to clean it out?

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coat hanger or screw driver, and then spray the **** out of it with brake clean and do an oil change.

89TurboBertone said:

coat hanger or screw driver, and then spray the **** out of it with brake clean and do an oil change.

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Ok. That's what I was thinking. Thanks!

Maybe even try putting a little low-pressure compressed air into that drain hole? Seal the drain hole on the outside of the block with a cork that has an air line running through the middle of it. (Oil-filler cap off of course.)