Frustration level 10! Round cap blown off top of engine Topic is solved

[Legofan]

I was kidding, hence the part about the pressure going somewhere else. Installing a new cap isn't going to fix what caused it to blow out. Did the dealer do a leakdown test or just put a glove over the dipstick and assume things were fine? You're not going to find anyone that has seen one of those caps blow out all by itself which is why people keeping telling you that the problem is elsewhere. Things like mileage, modifcations, etc. can all play a part in what might have happened, but you didn't mention any of those. You just assumed the cap fell out and the car was designed poorly but these engines don't randomly pressurize and destroy unless something isn't right. It sounds to me like you bought someone else's problem and nobody who's touched it so far has the slightest clue what they're looking at.

The dealer has it right now and they are investigating. They said they have never seen it happen. PCV system tested fine. It's been loose and I kept pushing it down which probably made it worse. I'll find out in a few days what they find.

[s10lowrider1994]

Hope they get it straightened out, I've never seen one dislodge all by itself. Maybe it was messed with previously and just wasn't in there very tight. If you get it back and they don't find anything other than the cap, keep an eye out for new oil leaks for a while just to be safe. Any sort of new seepage will indicate that there is excessive pressure and it's now finding another way out.

[mrbrian200]

keep an eye out for new oil leaks for a while just to be safe. Any sort of new seepage will indicate that there is excessive pressure and it's now finding another way out.

If there were that much pressure in the crankcase from excessive wear and blowby to push that cap out, wouldn't that pressure also be pushing oil into the cylinder on the intake stroke (white smoke, probably a lot of it)? I would imagine it would take no less than 20-30 psi to push that out.

I'm thinking a either a PO messed with it or you just happened to catch one of those freakish one in a million things (machining error on the valve cover or a hairline flaw in that cap that weakened it's grip). Three likely dealers near Evanston you probably took the car are known to have competent service departments. If there is something seriously wrong with the engine I'm sure they'll find it.

[Legofan]

Hope they get it straightened out, I've never seen one dislodge all by itself. Maybe it was messed with previously and just wasn't in there very tight. If you get it back and they don't find anything other than the cap, keep an eye out for new oil leaks for a while just to be safe. Any sort of new seepage will indicate that there is excessive pressure and it's now finding another way out.

I think someone did, it's always been loose and whenever I was under the hood I would tap it down with the end of a ratchet. My fauklt for not addressing it sooner but, it didn't seem out of place at the time. The front one hasn't budged.

[Legofan]

keep an eye out for new oil leaks for a while just to be safe. Any sort of new seepage will indicate that there is excessive pressure and it's now finding another way out.

If there were that much pressure in the crankcase from excessive wear and blowby to push that cap out, wouldn't that pressure also be pushing oil into the cylinder on the intake stroke (white smoke, probably a lot of it)? I would imagine it would take no less than 20-30 psi to push that out.

I'm thinking a either a PO messed with it or you just happened to catch one of those freakish one in a million things (machining error on the valve cover or a hairline flaw in that cap that weakened it's grip). Three likely dealers near Evanston you probably took the car are known to have competent service departments. If there is something seriously wrong with the engine I'm sure they'll find it.

It's at Fields Volvo right now having some evap work done as well as a new cap.

[precopster]

My cap started leaking on my 2001 V70 T5 around the edges and dropping on the exhaust. Used something like JB Weld (2 part metal epoxy) and so far so good. Hitting it in the middle to expand it at the edges sounds like sound advice from jimmy57

My T5 blew the dipstick out a couple of times however PCV is good. It happened both times after a full acceleration burst. New fatter O rings on the dipstick seems to have fixed it for now.

[ThommyKent]

keep an eye out for new oil leaks for a while just to be safe. Any sort of new seepage will indicate that there is excessive pressure and it's now finding another way out.

If there were that much pressure in the crankcase from excessive wear and blowby to push that cap out, wouldn't that pressure also be pushing oil into the cylinder on the intake stroke (white smoke, probably a lot of it)? I would imagine it would take no less than 20-30 psi to push that out.

I'm thinking a either a PO messed with it or you just happened to catch one of those freakish one in a million things (machining error on the valve cover or a hairline flaw in that cap that weakened it's grip). Three likely dealers near Evanston you probably took the car are known to have competent service departments. If there is something seriously wrong with the engine I'm sure they'll find it.

It's at Fields Volvo right now having some evap work done as well as a new cap.

I thought they had told you the PVC/Evap was fine? so it was building pressure after all?

[Legofan]

I thought they had told you the PVC/Evap was fine? so it was building pressure after all?

They did, evap(emissions) work is for the J hose at the charcoal canister in the back, it's cracked. As I understand it that is separate from the PCV system?

[Legofan]

My cap started leaking on my 2001 V70 T5 around the edges and dropping on the exhaust. Used something like JB Weld (2 part metal epoxy) and so far so good. Hitting it in the middle to expand it at the edges sounds like sound advice from jimmy57

My T5 blew the dipstick out a couple of times however PCV is good. It happened both times after a full acceleration burst. New fatter O rings on the dipstick seems to have fixed it for now.

I haven't had any issues with the dipstick and at idle I do have negative pressure. This happened right after full acceleration. I wonder if there's not enough blow off for the turbos causing high crank pressure but, I don't think those are linked.

[mrbrian200]

Compressor bypass valve is all on the intake side, in front of the throttle plate. Unwanted spike in charge pressure (if the valve is stuck shut) doesn't get past the throttle plate. So, No.