Pressurized crankcase = bad rings on ea82T?

[thecarman]

***Please do NOT mention an EJ swap in this thread. I'm going to start a separate thread about that once I diagnose the problem with my ea82T***

 

Issue

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On my ea82T, I have oil smoke coming out the oil fill tube, and there's oil residue coming out with the smoke. At idle, the oil cap rattles like a pressure cooker valve and puffs out smoke. If I drive the car real hard, like full throttle over 5k RPMs in first gear, the engine bogs and produces a big puff of smoke. I assume this is the engine sucking oil through the breather into the intake. If I shift, the bog is gone.

 

The car still idles and runs fine, and I have not noticed a drop in power (other than the bog mentioned above).

 

There is no water in the oil, or oil in coolant.

 

Breather/PCV system is NOT plugged.

 

Questions

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1) Is this bad piston rings?

 

2) Could it be a bad head gasket or cracked head?

 

3) Could it be anything else?

 

4) Any steps I should take to diagnose, prior to disassembly?

 

Background (I put this 2nd, so that folks could skip this part if they want)

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I bought an 89 GL-10 turbo 4WD wagon from NKX on this board a few weeks ago, with a known weak motor (he said there was low compression on one cylinder). Engine is stock with almost 200k miles. Has an MSD coil, cold air intake, and boost NOT adjusted higher than stock.

 

Car ran fine, but when we pulled it in the garage last week, I noticed smoke coming out of the oil fill tube after I pulled the cap. Went ahead and changed the oil, oil was clean, no water in it.

 

We ran the car in a rallyx this weekend - this is the first time we have driven it since buying it, it is not licensed for the street. (Car performed great - even with this issue! Will post a separate thread with my experience.) 2 drivers (we both own half the car).

 

I was getting on it pretty hard, hitting redline in first gear and then banging 2nd. We noticed some engine compartment smoke but weren't sure where it was coming from, then at the end of one run, when I was at 5psi boost going through the finish gate (I had just happened to glance at the boost gauge), the car bogged, dropped like 1000 rpm, and smoke came out the exhaust.

 

Popped the hood to see oil all over the passenger side of the engine, had come out the oil cap as mentioned above. Checked the oil, and the level was still in the operating range, so kept driving.

 

Ran the car the rest of the day and treated it a little easier, shifted sooner out of 1st gear, but did hit the "bog" once more.

 

Over the course of the day (a LOT of driving) the oil level dropped from top of operating range to 1/3 above lowest safe level. We were going to run the car for a 2nd day (it was a 2-day event), so rigged up a down tube off the oil fill tube to vent the oil/smoke down and out under the car, and also plugged the crankcase breather inlets on the intake (so it wouldn't suck in more oil), plugged the PCV, and routed the crankcase vent tubes (1 in each valve cover and 1 at center top of engine) down and out of the car. There is alot of smoke from the open tubes, but I think it would work. But this morning we were both so tired from yesterday's training/comp that we decided to skip today. So I don't know how my "modified" crankcase vent system would have worked to limp the car through the 2nd day competition.

 

Our next rallyx event is not until May, so we have time to fix the car, so want to diagnose the problem, then explore (in a separate thread) my options for fixing or swapping.

 

Thanks!

Richard

[Quidam]

Hi,

 

First things first. Do a compression check. If you're going to race, invest in a leak down test rig. It will tell you whether or not you have a motor.

 

Doug

[Turbone]

The EA82T is a closed system. It stays pressurized while running. The reason you are getting blowby coming up the filler tube is because the PCV system is plugged. Replace the PCV with OEM and check all the hoses. Most, if not all, will be hard as a rock from the heat. So alot of them will crack or be cracked already. They have a tendecy of filling with oil and sludge and restrict the flow of gases thru the system, hence the reason your pushing stuff out where it shouldnt.

I would also check the EGR while your at it, if it has one.

 

Should have read all the C/N's

 

Definatly check the compression. That many miles on a EA82T I would suspect the rings and valve seals are going.

[thecarman]

Thanks! What is a C/N?

 

For the PCV - When I pull the PCV hose at idle, I get suction thru the PCV valve on the manifold (a vacuum leak). If it was plugged, then I would not get that suction, right? Or I guess it could be partially plugged?

 

How does the PCV work when under boost? Doesn't it close because of the boost pressure in the intake?

 

I will check the PCV and EGR valves, as suggested.

 

I already pulled all the PCV system hoses in making my "oil/smoke diverter open crankcase system" temporary solution. None of the hoses were plugged or cracked. Some were hard, like you said, and should be replaced, but that wouldn't cause this issue.

 

Need to look in storage for my compression test set, or just go buy a new one. And I agree - leakdown would be the way to go.

[thecarman]

Here's a pic of how much oil is on the hood, from spewing out the oil fill cap:

http://www.triadfoundry.com/richards_pictures/subaru/GL10rallyMar08_5.JPG

 

Here's my Home Depot super ghetto divert-the-oil-and-smoke-so-you-can-breathe-in-the-car setup:

http://www.triadfoundry.com/richards_pictures/subaru/GL10rallyMar08_6.JPG

 

In that pic you can see the oil on the engine also (yes, it is really clean oil - the engine was really clean before, and we had just changed the oil)

[GeneralDisorder]

The crankcase is part of the manifold vacuum system. If your oil cap is loose and rattling then your mixture won't be correct. Any leaks like the filler cap or the o-ring around the dipstick ARE vacuum leaks to a fuel injected engine. They should be treated accordingly. Replace the rubber under the filler cap and adjust the ears till it's tight.

 

R&R the entire PCV system including the ports on the valve covers. They like to carbon up something feirce. It's best to remove the valve covers and get everything clean. Replacing the hoses isn't a bad idea, but the old one's can usually be cleaned with some effort.

 

GD

[thecarman]

I could not find my compression test gauge in storage, so will have to buy or order one, getting ready to look online now for what's available.

 

Will definitely check out whole PCV system. Good to hear that there could be *something* minor wrong with it, but I realize until I do the compression test I'll have no idea.

 

For a PCV system that is in working order, what keeps the two breather inlets on the intake side of the turbo (the suction side, not the compressed side) that are tied into the crankcase from sucking oil out of the crankcase? Just the fact that there's no oil there, just oil vapor? (Did that question even make any sense?)

[GeneralDisorder]

For a PCV system that is in working order, what keeps the two breather inlets on the intake side of the turbo (the suction side, not the compressed side) that are tied into the crankcase from sucking oil out of the crankcase? Just the fact that there's no oil there, just oil vapor? (Did that question even make any sense?)

 

There are baffles inside the valve covers to prevent that. But there's always oil in vapor form that is condensing inside the PCV system. Thus it eventually needs cleaning even if there's nothing wrong with the engine internally.

 

GD

[thecarman]

Thanks again. Compression tester and Leakdown tester have been ordered, and as soon as they get here, I'll post up the results. And will check out the PCV system parts the same night.