XC70 2005 crankcase ventilation

saq · Post by **saq** » 10 Oct 2016, 07:41

I'm trying to deal with my wife's '06 XC70, which as usual is an unpleasant shock compared with my '740. Seems Volvo is operating under the delusion that we all have a lift at home and are being paid $40/hr so don't mind taking everything apart to do what should be a simple fix.

Anyway (A) Anyone know where the instructions are in VADIS? Found them once, then I can't find them again. Skimmed what seemed like the relevant parts, then did a search, nothing. Plenty on diagnosing things that may be linked to the PCV, but no links to removing it.

I'm pretty sure that's where the problem is. Car started consuming ~3/4 quart per 1000 miles, oil smells more, and pulling the dipstick and leaving it out reduces consumption. That plus the 140k miles seem to indicate PCV. I've been looking around and it doesn't seem like there's any way to get at the parts to check for the blocked area without taking the engine apart, rendering the car inoperative for however long it takes to diagnose, order parts, and replace. Still figure I'll ask - any quick checks with the manifold on I can do to localize things?

Question 2: PTC comes up often, but the pictures I've found show it located on an 850, and they moved it for the P2s - and I haven't been able to find the pages in VADIS that show it. the XC90 tutorial doesn't mention it - is it still there? Where is it if it is?

Question 3: Looks like the $200+ octopus hose might be able to be re-tubed with new rubber and the metal bits cleaned out. Anyone tried this or looked at it with an eye to refurbishing?

Question 4: Where do you put the jackstands on this car? I usually put them under what looks like a rear suspension support bracket on the front wheel, but since nothing obviously screams out "frame component" I'm a bit leery.

fixer333 · Post by **fixer333** » 10 Oct 2016, 11:16

To check for excessive crank case pressure, remove the oil fill cap start and warm up motor and the cover oil fill opening with a rubber glove and seal with rubber band, run car for a few minutes rev up to 2000 and see if the glove inflates. If it does your PCV system is clogged( if all is ok it should suck the glove down against the grate in the oil filler).

Yes you have to take off the manifold to get to the "oil can" and various PCV plumbing.

The PTC is on the turbo inlet hose , right before the turbo.

I have 135000 and reused the "octopus", the rubber was still good ( soft, no cracks). The hose from the oil can to the valve cover was broken and the short hose from the oil can to the block( $70 cough ....) was dry/ hard , so replaced both of those, also the small round seal at the bottom of the oil can( oil return to the sump needed to be replaced).

There are a lot of articles on replacing these parts here and at other volvo sites.

I dont know what mechanism would causes oil burning when the PCV system is clogged though, if the oil return to the sump was clogged( which is common) I guess the the oil can could become full and oil sucked into the manifold banjo fitting or into the the hose that leeds to the PTC and then into the turbo.
Stuck/ or worn rings and or bad valve guide seals are the most common cause of oil burning( or if you have a turbo worn seals).

I know it can cause oil leaking at the seals , but a 3/4 of a quart leaking every 1000 miles would make a huge very noticeable mess.

Post by **vtl** » 10 Oct 2016, 19:15

If PCV is clogged, that's an indication of long runs on a crappy engine oil. Besides PCV you may have stuck piston rings. When you fix PCV, pour a couple of Seafoam cans into cylinders, let it sit overnight. It helps rotating crank +/- 15 degrees from time to time, so the rings move and Seafoam gets further into gum. Replace oil. You may need to repeat this treatment once a year or so, since the dirty rings won't be clean ever again and will be sticking again.

Replace the whole PCV, it takes a full day, no reason to cheap out. Blow air through lower oil drain hole, if you feel obstruction - drop the pan and clean the passage. Or just drop the pan anyway, clean and replace the seals

Also start using quality synthetic oil and replace it every 5k or so

crankycar · Post by **crankycar** » 13 Oct 2016, 20:40

I am at the same spot you are, but I leaked the oil due to clogged PCV, my glove blew up at idle and fast, just took the cat of to fix a broken pipe in the turbo mount flange, rewelded and checked catalytic convertor , it is clean, so will put together and drain the oil which I put ATF and drove to do some cleaning, had the cam tower off, oil pan and cleaned with oven cleaner as it was all that I found worked on the varnish, so this a rinse oil, so will see what my consumption is shortly will let you know, mine leaked out to the point the rear window got oily,mostly from the cap and top PVC hose, keep us posted what you find, I am going to use a Delo 400 for a 1000k to do additional cleaning, that oil is rated for 18 wheelers so it is top notch, and is spec,d for the newest Volvos, so will see what happens, will switch to the synthetic next change, will get oil in US as here it is crazy, those oils work very hard in those big rigs, even with the new exhaust filters, so this eng. is kindergarten stuff, my feelings are "nothing more expensive that oil, except no oil changes, so it is 5000k for me, this car is new to me so will see what happens..my pan passage was plugged solid, would not even let solvent thru...the flame arrestor was chuck full of gunk that couldn't go nowhere, what got me was the stupid location of the O2 sensor plugs, wow what a chore to unplug..