1998 V70 high crankcase pressure episodes

Post by **erikv11** » 28 Jan 2014, 09:52

All I can come up with is that oil is coming through the turbo. I have a small window of time right now, I am going to pull it and send it for inspection and rebuild.

Post by **jimmy57** » 28 Jan 2014, 10:39

Oil in intercooler certainly can be turbo. I can't see a way that turbo leakage pushes seals out.
You could have excess ring leakage only when cold. Leakdown test on cold engine might give you answers.

Post by **scot850** » 28 Jan 2014, 11:12

When you say you did the PCV, did you replace all the pipes and clean the PTC nipple? Have you re-checked to see that all the pipes are secure with no splits?

The PTC nipple being blocked will help the turbo pull oil and push it to the intercooler.

How cold was it when this happened? Folks are probably fed up hearing this from me, but up here in Canada when it gets cold, the intercoolers can 'freeze'. A combination of freezing air and oil build up in the intercooler holds condensation in the intercooler. With the amount of oil you are finding in the intercooler, I would re-check the PTC is 100% clean, remove and have the intercooler flushed, and finally drill a 1/8" hole in the bottom of the intercooler at lowest point to allow it to drain.

There may be credence to the sticking valve, but I would have thought you may have heard something. I'm not always a fan of the 'cleaning' products, but I have used Seafoam in both oil and fuel on a good run to help clean out deposits. There can be a rub on older engines that cleaning all the carbon may lead to lower compressions.

Lastly, had a similar, but not 100% as bad an issue with a 760 turbo. Rebuilt the head and replaced the head-gasket as dealer id'd the head gasket had failed causing all the seals to leak. Within a few thousand km the engine seals failed again. Removing the head I found the problem was a stuck/sticking piston ring. Ended up rebuilding the bottom end and all was good.

Really hope it is a simple fix.

Neil.

Post by **erikv11** » 28 Jan 2014, 12:22

Thanks for the input, I am definitely learning on this one.

I did a full PCV in August, replaced everything. Just inspected all PCV hoses they are good, PTC is wide open. The PCV system is almost bone dry, just a little milky white oil from condensation.

It was cold when it happened, it has only happened since December and has been a cold winter. Probably 15 F most days when it happened. The intercooler is draining well through the factory weep hole. You may be right about the intercooler freezing to blow the seals, but that doesn't account for a cup and a half of oil in the bottom of the intercooler does it? The turbo is pretty old (~180k with unknown history prior to my possession) so I don't think I am totally chasing ghosts there.

These comments about rings do worry me, keeping that in mind.

Turbo is pulled. Other than full of oil on the back side, I don't see anything suspicious. Shaft play is minimal. I'm going to send it for a rebuild.

Post by **jimmy57** » 28 Jan 2014, 13:05

You found oil in exhaust housing?

The leakdown test, or just airing a few cylinders at TDC with oil filler cap off to see if you have ring leakage cold. The ring end gap changes greatly when engine and thus rings, warm up. The end gap being huge and cylinder wall wear together can make for some big loss by rings.
This very common diesels. They will not use oil or have other symptoms other than they spin over too fast cold and will not start. Plug in block heater when you park hot engine truck and in the AM the motor is harder for starter to spin and it starts.

Post by **erikv11** » 28 Jan 2014, 13:08

Lots of oil on that side of turbo, yes. Fresh air side is pretty dry.

Post by **erikv11** » 28 Jan 2014, 13:09

Wait a sec - not in the exhaust housing itself. On the cold side of the wheel, leading to the intercooler.

Post by **jimmy57** » 28 Jan 2014, 13:16

I edited my post after you read it.

No, he said compressor side is dry.

The exhaust side turbo seal, which is a piston ring like steel seal, can fail and lose oil on the exhaust side. The seal will get stuck in its groove.

Post by **erikv11** » 28 Jan 2014, 13:29

OK, I can check the cold cylinders later tonight.

So would ring leakage draw oil through the turbo though, or would that have to be a separate problem?

Post by **MoVolvos** » 28 Jan 2014, 19:57

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Sound like the Wastegate is not working fast enough to dump but the problem is the Turbo. The extra oil is from pressure from the exhaust side encroaching into the Intercooler side and taking oil along with it. It may go both ways exhaust pressure or intake pressure. Is the Throttle body wet? Someone who understands well the Turbo system and it is function maybe able to add more insight.

Blessings,

BKM
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1998 V70 high crankcase pressure episodes

Re: 1998 V70 high crankcase pressure episodes