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mysterious splat of oil out of filler tube
by
zuhandenheit
on 17 Jan, 2018 17:23
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A few days ago I installed a new K03 on my AAZ and moved my oil drain from the block to the pan (this is in a vanagon). I'm chasing a lot of bugs in my conversion. I also swapped in a new-to-me rebuilt IP, about which I posted in a separate thread. I had R&Rd the IP and was trying to adjust the idle, which was too high, when suddenly the motor started spitting oil out of the filler tube. It has never done this before. The crankcase vent runs to a catch can which has never filled up. I've never had reason to suspect that I have excessive blowby, piston ring problems, or crankcase ventilation problems.
It just suddenly spat oil out of the filler tube.
I shut off the motor, checked that I hadn't like left a towel stuffed in the crankcase vent when it was apart or something when it was off (I had removed it and the hockey puck to better access the IP). I started it again, now concerned not with the high idle, but to see it the motor would spit out oil again. It did it a second time, and I shut it down.
I looked over everything and could find no problems, so I started the motor again and went back to sorting out the high idle. I got this fixed. The motor didn't spit oil again. I took it for a drive and all seemed well.
Here are some possibly relevant facts:
I just filled the motor with 4.5 quarts of oil.
I have just made an oil drain line to the pan, to go with a new turbo.
I discovered a few days ago that my old air filter was soaked in oil. This must have come from the turbo, when the piping between the turbo and intake manifold came apart and on account of an inadequate oil drain / bad seals, the turbo was leaking oil into the intake. I cleaned the filter and bought a new one. Right now I'm running the cleaned filter. The new filter arrived today.
Again, the motor has never done anything like this before. I had just reinstalled the IP and was in the process of getting it sorted when this happened.
What the hell?
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#1
by
libbydiesel
on 17 Jan, 2018 21:45
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The only reason I can think of for oil to be pushed out the oil filler tube is because of excessive crankcase pressure. I don't have an AAZ valve cover in front of me... does it have a screen that is under the crank vent opening? Any chance that has gotten plugged or semi-plugged? You said you run to a catch can, is there any potential resistance to crankcase gases leaving the can? Do you have the block port/tube connected also?
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#2
by
zuhandenheit
on 18 Jan, 2018 10:42
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I have the OE tube from the block to the valve cover, and a hose running from the puck to a catch can. There's no screen on the valve cover. I can check the hose to the catch can for blockages. I took a long drive last night with no issues, and a short drive again today -- no issues. I've heard of this problem but never experienced it myself, before now. The hose from the puck the catch can is not a proper oil rated hose -- it was a quick fix when I was first getting things together, and a replacement is on my list. It's getting a little spongy. I had to remove it when I was dealing with the IP, and maybe it got folded/kinked or something. I shut the motor down very quickly when the oil stream began and I didn't get a very good look at things, but I didn't notice that the hose was crushed or anything. However this is about the best I can figure . . .
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#3
by
zuhandenheit
on 18 Jan, 2018 14:51
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So far this hasn't happened again, and I've done a bit of driving including lots of full throttle runs (checking that things are tuned as well as possible) and lots of idling, as I test and monitor the engine. It was such a damn weird freak occurrence. I think I'll take apart the breather system and catch can and have a look.
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#4
by
libbydiesel
on 18 Jan, 2018 19:46
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How is the pressure vented from the catch can? Any chance of a blockage there?
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#5
by
libbydiesel
on 18 Jan, 2018 19:48
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I would also mention that if there is an air filter restriction (e.g. plugged filter, collapsed hose, etc...) then the valve in the hockey puck will close and the pressure in the crankcase will rise which could cause the oil to puke out the filler tube. You might still be tracing an issue with the intake setup.
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#6
by
zuhandenheit
on 19 Jan, 2018 13:31
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Aha -- I wondered if the intake could be the problem, but I didn't have any idea how. I cleaned the oil-soaked filter as well as I could, and there was surely a big improvement, but I didn't get my replacement filter until yesterday. Even after cleaning, the old filter was nearly black. Also, at the time that this happened, I was trying to fix the idle issue (now resolved), and the motor was spinning a lot faster than idle (which would increase the risk of this happening). My boost gauge was no longer showing a vacuum, but I'll bet there was still a restriction.
I could take some pictures of my catch can. There's a hose from the can that vents to the atmosphere -- no filters or joints that could be clogged, as far as I know. The can itself is a sturdy steel box I bought on Amazon or something. It has a tube on the side that shows the oil level, and I've never even had to dump it.
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#7
by
burn_your_money
on 19 Jan, 2018 23:28
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If you have a very large vacuum leak, the vacuum pump will force lots of air into the engine which will force oil out the dipstick tube.
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#8
by
ORCoaster
on 20 Jan, 2018 00:24
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Does the vane style vac pump pull more air into the engine than the older diaphragm style pump? Not quite sure what the volume calculation would entail on something like this. Maybe a CFM measurement would be all that it would take to answer the question.
I am wondering if by switching over to the newer style pump I am now moving more air through the block and into the air filter box.
Anyone have a solid idea on this?
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#9
by
libbydiesel
on 20 Jan, 2018 15:56
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Considering that the volume of the system being evacuated and the inHg of vacuum are similar regardless of what pump is doing the evacuation, then provided there are not any leaks then the airflow into the block would be the same.
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#10
by
burn_your_money
on 21 Jan, 2018 13:26
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Correct me if I'm wrong, but if nothing is using any of the vacuum, then there should be no air flow through the block. Or is that not how these work?
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#11
by
libbydiesel
on 21 Jan, 2018 15:36
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I believe you are correct. Once the max vac is reached, no more air is pumped into the block by the vac pump. There will still always be some blowby past the pistons that enters the block.
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#12
by
zuhandenheit
on 25 Jan, 2018 04:08
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Obviously, I've got my fingers in a lot of pies (like, engine pies). Tonight I got an intake put together. It's not finished, but usable, and I really wanted to know how the motor runs with a muffler. There's certainly a difference, though I'd like to quiet it down a bit more!
I took a drive of maybe 30-45 minutes, and did some freeway runs.
On the way home I had to brake very hard, and saw a quick flash of the oil light. That means the oil level is slow. I had lost some here and there over the last couple weeks, but I was surprised to see it low!
I got home and immediately saw oil dripping from my new muffler. It seems the dipstick did it's thing again. It doesn't seem to have been a terrible amount of oil, but I'll check more closely tomorrow.
I'm really thinking it could be a vacuum leak after all. The hoses are not too inspiring, from their appearance. What's a good way to test for a vacuum leak?
Thanks to everyone for all the help, and my apologies for all the posts. I've been really busy with this thing.
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#13
by
zuhandenheit
on 25 Jan, 2018 04:24
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I should mention again: I'm not seeing any significant amount of oil at my catch can!!
So I think I should take it off and check that there's some pressure there. Maybe the hock puck failed or something . ..
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#14
by
burn_your_money
on 25 Jan, 2018 14:10
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I'm really thinking it could be a vacuum leak after all. The hoses are not too inspiring, from their appearance. What's a good way to test for a vacuum leak?
The best way is to just replace them
So you have oil dripping out of your muffler?