Low oil pressure and suspected high crankcase pressure

[JEL91Westy]

I have been chasing oil pressure issues and oil leaks since a rebuild 2000k ago. I am beginning to suspect the oil leaks are being caused by high crankcase pressure as I have noticed the dipstick protruding 1/2” out on several occasions. Excuse my ignorance, but how can I have low oil pressure with high crankcase pressure? I installed a new breather tower, and am about to look at the vent system again. I have no smoke, but the oil smells like exhaust to me. Could this be caused by rings?

Thanks in advance for any suggestions.
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91 Westy
85 911

[jlrftype7]

I see you have the 2.1 , with the Dynamic Oil pressure system. Is the warning system going off on you- Engine has to be hot, or shortly after starting, during warm up?
Have you moved to an Oil pressure gauge set yet, to get real readings of engine oil pressure?
You seem to have several separate issues going on at the same time. Oil leaks could be related to crankcase pressure though.
Oil pressure issue is a clearance issue somewhere, esp after a rebuild that soon. Something is off- Did you install a new oil pump? Reuse the old pump- reuse the cover- possibly get the clearance wrong on the cover to pump/block even with new parts?
If you did main bearing work, crank grinding etc, did a Plastic Gauge check show correct clearances?

Crankcase pressure- A leak down test is needed since you are seeing Dipstick getting pushed out. You could have rings that didn't seat against the cyls- Ring gap issue- Or ring gaps that are aligned, not spaced apart, and allowing pressure past the rings.

Oil leaks could easily be related to the above Crankcase issue- On our previous 1.9 engine, when we bought the Vanagon in the Fall of 2018. You couldn't run the engine very long- totally clogged crankcase vent system would build up pressure, and once you turned the engine off, the excessive pressure would pop through a Pushrod Tube seal at the drivers front of the engine, and literally piss on the ground , making a high pitched shrill sound along with the oil stream as the pressure escaped.
It was like clockwork every time. Luckily the Vanagon wasn't ready for the road yet, so once I replaced Oil Breather Tower, lots of hoses, flushed the engine- replaced all the PushRod Tube Seals and used Spring Loaded Aftermarket Pushrod tubes , all that stopped thankfully.....

Yours sound more like a rebuild went amiss somewhere. Sorry you're going through that-it's probably more painful than our wornout engine blues were, since you've spent time and money trying to make your engine better.

As an aside, that engine of ours never stopped guzzling oil, esp at highway speed trips. Cyl 4 was the worst of the cyls for burning oil. I still haven't torn it down now that it's out of the VW, to do an inspection of what exactly was wrong- scored cyl, worn rings- broken oil control ring etc. Cyls 1 and 2 were fine- zero deposits on the plugs whenever I checked.
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'68 Westy- my first VW and vehicle/Bus- long gone.- sold it to a traveling Swiss couple....
'67 Type 3 Fastback, my 2nd car- gone
'69 Semi-Auto Stick Shift Beetle-gone
2017 MINI Coopers, our current DDs
‘84 Tin Top - Hilga....Auto

[zerotofifty]

oil pressure and crankcase pressure need not be related, separate items. you aint ignorant.

[dobryan]

This sounds like a potentially sloppy rebuild...
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Dave O
'87 Westy w/ 2010 Subaru EJ25 (Vanaru) and Peloquin TBD

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[JEL91Westy]

Thanks for the responses, this answered my ignorant question - oil pressure and crankcase pressure are unrelated.

On rare occasions I was getting low oil pressure warning on hot engine, off throttle, this was with the new pump on the rebuild. The builder replaced the oil pump again a week ago and so far the pressure on the oil pressure gauge I installed in the dash looks better. I continue to have oil weeping at main seal, valve cover gaskets and some of the nuts on the case bolts. It does not burn much oil and runs well.

Spent last night reading numerous posts on the breather tower. I am going to pull that off and try to confirm it is working properly next. I may just put the old one on and see what happens, which is what the builder suggested. I must admit there is a lot on that topic and it is a bit confusing to me after discussing with him. At idle I have noticeable pressure coming from the nipple on the tower, but at higher RPMs it is almost nothing. That seems counter intuitive to me, and it would seem their should be a way to check it shy of removing it and trying to blow or suck through it. I need to look through those threads more carefully and will post to one of those instead of continuing on that topic here.

Thanks again.
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91 Westy
85 911

[jlrftype7]

[Wildthings]

There is an orifice in the breather hose, make sure it doesn't have something blocking it. A hollowed out breather tower seems to work fine in my experience. Years ago when I changed a bad breather out for a brand new factory one, it made no difference in how much oil the ratty old engine that was then in my 83 1/2 used.

[JEL91Westy]

Thanks for the help. No clog at the heater.

I moved my issue to this thread with more info, as I thought it was more appropriate.

https://www.thesamba.com/vw/forum/viewtopic.php?p=10268078#10268078
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91 Westy
85 911

[Wildthings]

delete

[E1]

[Wildthings]

Maybe use a hose without the orifice as per the 1.9L engines, at least until the rings settle in better.

[IdahoDoug]

Wow, I dont like to criticize a mechanic, but leaking valve covers. Leaking main seal, and what appears to be leaking piston rings just a couple months after a rebuild? Would you mind posting your receipts from the rebuild here so we can see what was done and provide better advice? Feel free to block any personal info with a postit note or similar.
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1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1993 Toyota LandCruiser, 2002 BMW 325iX, 1982 Toyota Sunrader

[johnnygreenham]

Had a similar issue after rebuilding my diesel AAZ. I know it's a completely different engine and system but the principles are kind of the same. The first time I had a crack at it I did not have the cylinder walls rebored but turned out one was slightly elliptical and soon after, with new rings, that one cylinder started to miss occasionally on warm up. The biggest sign that something was off was that my dipstick would keep popping off but worse oil would get blown all of the back of the engine bay.
I had a second go at rebuilding it, this time I did absolutely everything including having the cylinders rebored to their largest size. I was meticulous with everything and once the engine was put back in I did a very extensive break in procedure. I still had the dipstick popping off but not as bad! That really surprised me for sure and I was starting to think I just sucked at rebuilding engines but I temporarily removed the dipstick a replaced it with a blank cap and at the same time I also made by own non restricted breather/oil separator with an oil overflow catch container to deal with the excessive crankcase pressure. After about 500-700 miles the rings seem to wear to the cylinder walls and everything stopped leaking. It took a good couple of thousand miles to seemingly completely disappear. It was a little nerve-racking at first to see so much pressure build up but it figured itself out. 60K+ now on it and still going strong so don't lose hope yet.

[/url]IMG_3309 by jonnygreenham, on Flickr[/img]
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1982 Diesel 1.9TD AAZ

[JEL91Westy]

Based on the advice of Wildthings and E1 above, I deleted my post from the other thread and am adding it below. Sorry for the confusion, I just thought that was a more appropriate thread. Thanks for all the advice.

—————
“I had started a new thread to try and get my head around the relationship, if any, between oil pressure and crankcase pressure. That answered, this is a more appropriate location to discuss the crankcase pressure mystery I am dealing with. I have read this thread 3 times and the longer linked thread on this topic once.

I suspect high crankcase pressure on a recent rebuild with very little oil consumption and no smoke. The dipstick has been pushing out, but no oil was being expelled. It has a relatively new breather tower. In trying to sort this out I disconnected the hose on the tower side of the heater and noted the positive pressure at idle and 3k, it seemed to increase with RPM’s if that makes sense. I then clamped the hose shut so there was not vacuum on the intake side, seemed like roughly the same amount of positive pressure coming from the tower. I then accidentally drove the van with the hose disconnected on the tower side of the heater. This resulted in the dipstick protruding even further and for the first time oil being expelled from the dipstick tube. So more pressure with the hose between the tower and the intake being disconnected ? I am completely confused now. I know it is venting when running because of the positive pressure and even with it venting wide open I still seem to have excess pressure based on the dipstick. WTF!”
—————

Couple things to add, it has new pistons and was bored our to 2.2, new crank, cam, heads. I wanted to do everything in the hopes of getting 200k out of it again, but I am having more problems then I had on the old motor with 1/100 the mileage! I meticulously followed a break-in procedure found here after much reading. The engine builder has done a lot of rebuilds and this one is troubling him. I removed and reinstalled the motor. He is trying to help me work through it, and at his suggestion I am going to cleanup and install the original breather tower today. The fact that the dipstick pushed out farther and oil came out with the breather hose disconnected is what is really baffling me. Given this I can’t see how the old tower would help.

As far as it being rings, I have pulled the plugs multiple times and they all look okay to me. I am not burning oil or smoking. I am going to have a friend that rebuilds Porsche engines help me do a compression test and leak down next week.

Thanks again.
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91 Westy
85 911

[IdahoDoug]

Proper leak down/compression will tell the story. Your rings are leaking compression pressure into the crankcase, which is full of oil vapor. The vapor becomes the leaks. Not sure why you are not going to post your receipt, but there are people here who could point out things like "Well looks like the part number for the rings is the wrong one." and related.

I'm kind of bothered by your mechanic having you do things are are a bit nonsensical. As if he wants to tire you out doing little things, while you slowly accept your fate that the engine has something inherently wrong that he did not do. You can scarcely do anything wrong installing an engine to cause it to burn oil and leak oil. He knows it but he wants you to slowly conclude somehow it's your fault. Since you're not using the collective minds here as an advocate (receipt), I'm glad you have a friend there who will shortly find the issue. Be sure you show HIM the receipt so he can look over what was done. To a highly mechanical person like him and many here, that piece of paper provides clarity like a road map. And I'm hoping you don't say "I was never given an itemized reciept because he's a trusted friend...." Best.
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1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1993 Toyota LandCruiser, 2002 BMW 325iX, 1982 Toyota Sunrader

[Wildthings]

People have mentioned that some of the replacement breather towers lack the vent hole under the lip of the top cap, which prevents the breather from opening correctly. As I previously suggested you could run a plain hose with no orifice between the breather tower and the S-boot as per what was used on the 1.9L engines and then once the rings get fully broken in go back to the hose and orifice set up.

[JEL91Westy]

Yep, this - “ hoping you don't say "I was never given an itemized receipt because he's a trusted friend...." I have an invoice with the parts listed, but not part numbers.

He has worked on all my VWs for 35 years, and I trusted him to do it right. He has been the go to guy for VW engine work in this area for a very long time. Until I independently verify via a leak down and compression it is the rings, I am not going to cast blame.

Still would love to understand why the pressure appeared to go up with the breather hose off.

Thank you.
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91 Westy
85 911

[JEL91Westy]

[Wildthings]

The old breather combined with no orifice in the hose is going to give you the most ventilation. You can pull the guts out of the old breather through its bottom to make sure there is not anything blocking the large passage.

I found that the original breather on my 83 1/2 was blocked off by a piece of the old failed diaphragm that had glued itself in place blocking all the flow through the breather.

[JEL91Westy]