Oil in air filter box?

[bblument]

Dear all,

I've been reading this board for a month or two and have learned a great deal. My last project was a 1992 Volvo 240 which needed a great deal of work, and the folks over at brickboard.com were amazing.. if any of you have Volvos, that's the place to hang. I had all but given up on finding a similar place to learn about my current project (1982 Rabbit convertible), but then I found you all... wonderful!

Here's the background on the vehicle.. as stated above, it's a 1982 Rabbit convertible, but we rebuilt a 1.8L engine (I think it was a 1984, maybe from a Golf, but I'm not positive) and put it in. The original 1.7L engine was shot, and we had a hell of a time trying to find pistons for it so we gave up and just rebuilt an engine for which parts seem to be more widely available.

I'm slowly going through a bazillion electrical gremlins.. this car sat for over 10 years. I haven't given up on anything here yet, though.. when I do I'll probably enlist your help.

Here's my current dilemma. The air filter is soaked with oil, and the car leaks oil out of the plastic housing where the cold and pre-heat intake hoses join. The preheat hose is gone (and will remain gone.. I learned that lesson on my Volvo 240). There's lots of oil in the air filter housing. What's causing that? I can't tell you what my oil pressure is because I currently have the wrong oil sensor on the valve cover (only one terminal instead of two), and the gauge on the center console doesn't read properly. I only see one fairly large vacuum hose connecting the valve cover to the air box, so I'm assuming that's where the oil's coming from. Can anyone advise me as to a step-by-step troubleshooting procedure? I've checked the vacuum routing against some info I found here, using the 1980-1983 CIS diagram, and all looks correct now. The vacuum advance and distributor vacuum lines had been reversed; I just found that and the engine's running a TON better. It used to start awful when it was cold.. I'm letting the engine cool now and I'll try and start it again in a few hours. Hopefully, it'll hold idle right away now instead of requiring 12 starts before starting to smooth out.

I should probably shut up now... I could ramble forever about all the issues, but at least she's finally on the road and running fairly strong now. Just gotta find out what's causing the oil to flood the air filter housing and leak out.

Ideas? Thanks in advance. Best to all.

Barry

[briano1234]

Take the plugs out and Check compression for each cylinder. Excessive oil in the Air box, is usually a valve seal leak, or a ring problem. There isn't a true PVC or EGR system. The Top of the Valve cover there is a hose that usually goes to the Throttle body, but some one may have routed it to your airbox.

On a diesel it does go to the air filter and they do get oily, but not on a CIS. Unless you are shipping more oil out the Valve cover than the system can suck in and the oil is draining back in to the Air Box.

See www.cabby-info.com for hose routing.

[ShoddyElectrician]

Also there is a tiny breather on the right side of the head between the cover and the runners of the TB. I hear that can leak quite a bit of oil if you oil baffle is broken or removed and mine was connected to a line that went to the air box.

I didn't see any use for the air box to be in that system so I plugged up the line. Is there something wrong with that? Because if he took the air box out of the system then we could see if its that or something more serious. I ran my hoses:
Vacuum feeding off the right port on the TB, valve cover breather to the left and then tapped that breather line for the small breather.

[bblument]

Thank you both for taking the time to reply with your thoughts. Here's an update...

I'm fairly sure there aren't any compression issues; we did a complete rebuild of this engine including new pistons, rings, bearings, everything, and a reman head. While I'm at best a borderline competent shade-tree mechanice, I had two friends help me with the project and they're both highly respected full-time professional mechanics.

I just pulled the short but fat L-shaped vacuum hose that runs from the valve cover to the intake manifold just to check it, and sure enough it was completely blocked. Someone at some point in the car's previous lives had inserted a metal plug inside the hose. I had to slit the hose to get it out, but wrapped the slit thoroughly afterwards until I can get a new hose. The good news... that's solved the oil-in-the-air-filter-box issue. Prior to finding that plug, the vast majority of positive pressure had been flowing through the other large hose that's routed to the breather box (correctly, according to the vacuum routing diagrams you referenced, Briano). Sooo... oil pooling, leaking, and loss solved, I believe.

Now, the bad news. Prior to unblocking that vacuum hose, the engine was running well, held an idle well after a few minutes of warming up, and the car had decent power. Now that I've unblocked that hose, it almost always stalls at idle and when it does hold the idle it's very uneven. The car is still driveable, but now it has much less power (although it sounds smooth above 1500 RPM) and knocks like crazy. It never knocked at all before. I've tried readjusting the timing (by ear/trial and error), but nothing seems to help. If I remove the aforementioned hose and hold my thumb over the large exposed nipple on the intake manifold, the engine smooths right out instantly.

Sooooo.... why? Why did someone plug that hose in the first place? Is it possible they plugged the hose then readjusted the idle and/or mixture settings for that plugged condition and now those settings are off enough to screw up the engine with the hose UNplugged? I guess I'm going to head out and remove and clean all the other vacuum lines and see if there's any OTHER goofiness. Oh.. an aside.. now that I've cleared that one hose, the vacuum-switch-activated upshift light is working in the dash. It was always continuously lit up until now.

Further ideas not only welcome, but greatly appreciated. Thanks in advance!

Barry

[briano1234]

That wasn't a plug but a restrictor. There should of been a hole in it. You have given your engine a large vacuum leak.

[bblument]

That wasn't a plug but a restrictor. There should of been a hole in it. You have given your engine a large vacuum leak.

There were actually two obstructions in that hose. One was obviously NOT meant to be there; it was a small threaded plug about 1/2" long with a square head (like the tuning lugs of a snare drum, if that makes any sense). It was completely blocking the hose. Also in the hose was something that may have been the restrictor to which you're referring. It's a rigid tube about an inch long with a raised ridge in the middle. I'm going to go back out to the car and put it back in.. maybe that'll help. Thanks for the tip.

More news... I discovered the hose that's supposed to go from the head (incorrectly labeled in the diagram as going to the "intake manifold," but I saw your post stating that you hadn't gotten around to correcting that so I know what you mean) to a "T" fitting underneath the short rubber bellows attached to the throttle body that also connects to the large tube going to the charcoal canister. On my car, there's no "T".. only a single "L" connector for the canister hose to fit into the bottom of the rubber bellows. The hose that's connected to the head is simply plugged and going nowhere. I'm going to pick up a "T" connector tomorrow and get that hooked up properly.

All the other hoses seem to be hooked up properly, leak-free, and not blocked. I couldn't really blow much air into the hoses coming to or from the charcoal canister; is that normal? Pardon the stupid question, but what exactly does the charcoal canister do? How about the "expansion tank" that's under the other fender? Both are in the vacuum system, but I don't really understand what they're for. Could one or both be part of the problem?

Thanks again..

Barry

[bblument]

Quick update.. With the restrictor back in the valve-cover-to-intake-manifold hose, the car is running much better again. No knocking, decent power, and it holds the idle nice and smooth once fully warmed up. The upshift indicator light is back to being on all the time, but I can live with that for now. Thinking out loud here... if the upshift indicator light was working properly when the restrictor was removed from the hose, then THAT small part of the vacuum system (the small drinking-straw-like tube running down to the vacuum sensor T'd off from the vacuum advance) must have been seeing the pressure (or vacuum) it wanted to see. Now that the restrictor is back in and the engine seems much happier, the pressure (or vacuum) for the upshift sensor is no longer strong enough. Sooo... something's still plugged somewhere and the system's still out of balance. Perhaps the hose re-routing I described in my previous post will take care of everything... what are my odds? <grin>

Barry

[briano1234]

Well, getting the hoses back to the way they were intended to run is a good thing.
You can always pull the Vacuum to the up-shift light from another source.

[bblument]

Yet another update --

Picked up a T fitting and some new hose yesterday and now have everything routed properly per the vacuum diagram. Upon doing so, the idle increased up to almost 2000 RPM, so I readjusted the timing until I got a smooth idle at about 800 rpm. Upshift indicator is working properly, the car is idling very steadily, and driving pretty well. Right now, it doesn't seem to have QUITE as much power as it did with the hose simply plugged coming from the head, but that's subjective.. I could be wrong. I didn't check the idle adjustment screw to see if the anti-tamper plug had already been removed; I'll check that tonight. Perhaps someone adjusted the idle mixture to compensate for all the incorrect vacuum stuff. I have a copy of the detailed pdf instructions for adjusting the idle mixture, AND another thread dealing with troubleshooting cold start issues (still a big problem for my car). Which would be the best place to start... solving the cold start stuff (cold start valve, CPR, etc, temp sensor, etc) or idle mixture adjustment?

Thanks again..

Barry