Last night I was prepping my '91 Legacy for a trip to Portland. It was sitting in my driveway just idling and I was moving tools and stuff for the trip. Suddenly, huge amounts of white smoke came out the exhaust....I mean huge....enough to cover the car behind me. I shut off the engine thinking head gaskets. I let it sit for an hour while I made a trip to PAP. When I got back, I checked the coolent...just fine. I started up the car with the radiator cap off and got no bubbles or coolent out the radiator but still had massive amounts of white smoke. It didn't smell like coolent, more like the acrid smell one gets from burned oil. The car still runs and idles normally but I didn't get a chance to test drive it (getting dark) but I'll run it more when I get home Friday. Two weeks ago we installed a new timing belt and replaced a bad water pump. Two days ago I installed a new PCV since I was loosing oil (about a quart every 1000 miles) and I thought it might be time (car has 153K on the odo). I haven't had a CEL for a week and didn't have one now. Any thoughts as to what caused this or what I should check next. Thanks.

Manual or automatic transmission? As was discussed in a thread with moosens, white "smoke" is either water vapor or ATF. Water vapor disappears into thin air, whereas any oil smoke (including ATF) dissipates through dilution.

ATF would be one of the first things to come to mind, but I don't think the 4EAT has a vacuum modulator, or does it?

 

Did you use a genuine SOA PCV valve? I don't know how finicky the EJ engines are about that, but on my EA motors, anything else WILL cause them to burn oil. (I just put a new PCV valve in my EJ22 because the old one had some significant rust on it:rolleyes: , and it was puffing out a blue cloud at startup...I really hope it's not valve seals:-\ .)

Try replacing the PCV valve Ed.

Ed's LS wagon is a 5 speed.

 

My guess is its engine oil burning off somewhere from a bad seal or something... like valve seals or something like that?

If it doesn't smell like toasted marshmallows, it must be oil of some kind or fuel. I vote for PCV valve being bad or on backwards or some weirdenss like that. New parts can be bad.

Yes, start with the PCV valve. Again.

 

White smoke is almost certainly water, and MAYBE the PVC is pulling condensation from the crankcase and causing the engine to steam.

 

A leaking head gasket - God forbid - would produce a lot of smoke for a very little amount of coolant, so it would take a while to notice a drop.

Manual tranny.

Manual or automatic transmission? As was discussed in a thread with moosens, white "smoke" is either water vapor or ATF. Water vapor disappears into thin air, whereas any oil smoke (including ATF) dissipates through dilution.

I replaced the PCV valve two days before the smoke appeared with genuine Subaru part.

Try replacing the PCV valve Ed.

Not sure how I could screw in the PCV backwards; only threaded on one end. I used genuine new OEM part.

If it doesn't smell like toasted marshmallows, it must be oil of some kind or fuel. I vote for PCV valve being bad or on backwards or some weirdenss like that. New parts can be bad.

Not sure how I could screw in the PCV backwards; only threaded on one end. I used genuine new OEM part.

 

Yeah, I dunno, maybe some hoses got misplaced or something?

I have seen a new PCV valve fail and it smoked just like your did. If you still have the old one I would try it out.

Ed,

Do a compression check. I know old and new gen are different... well sort of... since they run off the same principal.

 

The smoke I saw from mine was definitely white and smelled of extreme exhaust... not sweet, (toasted marshmallows) or mild exhaust.

 

In the end, one cylinder was at 35 psi, while the others sat at around 150. The oil was very thin (no viscosity) and heavily laced with fuel.

 

I don't know what was wrong, but a new j/y motor solved it.

 

Now, if we can only fix that right front wheel.

Best of luck that it's the PCV:)

What does PCV valve do?

Would it encourage to use excess oil?

 

I did a compression test on mine and they're around roughly 165-170psi on a old worn gauge.

 

Engine runs fine, no mis-fire, new sparkies, low kilometre (50,000klms) O2 from EJ20 Impreza.

Cheers

AP

yep methinks it's toast.. sell it to me :D j/k Ed, I'd check the PCV first, adn do a compression check... hey, when you had it idling, did you have the car level, or was the nose of the car facing downhill? Might have just been enough to make it suck oil past the PCV..

Car was facing slightly downhill. Thanks for the tip.

yep methinks it's toast.. sell it to me :D j/k Ed, I'd check the PCV first, adn do a compression check... hey, when you had it idling, did you have the car level, or was the nose of the car facing downhill? Might have just been enough to make it suck oil past the PCV..

PCV valve removes exhaust blow by and pressure from the crankcase. It has a ball in it to prevent any possible backfire in the intake system from reaching the gases in the crankcase. It should rattle when shaken.

 

Use to be, there was no PCV, and the oil cap was open to allow venting. Of course, this blew all that crap into the air, which isn't real good, so they came up with the PCV system to suck it back in and burn it.

 

If it only does it at startup and doesn't smoke all the time, it could be a bad valve seal.

If the compression tester doesn't show leaky valves/worn rings, is there any way that I can find out if the valve seals are out - are they easy to replace even if the heads on the engine?? or the heads has to come off?

 

Mine only does it at the startup, but doesn't do it while I am driving the car (but I noticed it does use oil) btw its EJ22.

Cheers

AP

Btw I'm not too sure if this is correct, the PCV valve is small about one half inches long? Its non Electrical?, it does rattle inside it?, but it was covered up in oil snoot & carbon build up, so I cleaned up with Carby cleaner looks like it did it as treat. Its connected to a big pipe to a smaller pipe that goes into the manifold on the right side of the engine (air box side) is that the correct one?

 

How do I tell if I need a new one?

Cheers

AP

Usually if it doesnt rattle, you need a new one. Cleaning them just ungums them, but you should still replace it.

 

 

nipper

Usually if it doesnt rattle, you need a new one. Cleaning them just ungums them, but you should still replace it.

 

 

nipper

 

I've already thought about going ahead buy a new one, are they expensive?

Cheers

AP

It's not expensive; I just paid under $10 to www.1stsubaruparts.com for mine. Common opinion on the USMB is not to buy after market for this part; genuine OEM is best in this case.

I've already thought about going ahead buy a new one, are they expensive?

Cheers

AP

Pulled the two day old PCV and it was stuck closed with some kind of gunk so I put the old one back for the time being. But while I was doing that, I noticed all the hoses from the crankcase area and valve covers all meeting and feeding into the throttle body air intake. I thought about the air cleaner and pulled the housing. Air cleaner was pretty well clogged; I have a K&N and haven't looked at it in way too long a time period. I cleaned the filter, oiled it and re-installed it. Most of the smoke is gone and all gone when the engine is warm. Smokes a little when I start it up cold, but I'm thinking of adding some Seafoam to help clean out the plumbing.

Pulled the two day old PCV and it was stuck closed with some kind of gunk so I put the old one back for the time being. But while I was doing that, I noticed all the hoses from the crankcase area and valve covers all meeting and feeding into the throttle body air intake. I thought about the air cleaner and pulled the housing. Air cleaner was pretty well clogged; I have a K&N and haven't looked at it in way too long a time period. I cleaned the filter, oiled it and re-installed it. Most of the smoke is gone and all gone when the engine is warm. Smokes a little when I start it up cold, but I'm thinking of adding some Seafoam to help clean out the plumbing.

 

Not only does sound like you may have escaped a serious problem, but you solved the mystery, probably be an easy fix - and you get the satisfaction of fixing it yourself! how cool is that?

As per 1 Lucky Texan, "But even so amid the tornadoed Atlantic of my being, do I myself still forever centrally disport in mute calm; and while ponderous planets of unwaning woe revolve round me, deep down and deep inland there I still bathe me in eternal mildness of joy."

 

Apparently consternation turns to lucidation!

 

Not only does sound like you may have escaped a serious problem, but you solved the mystery, probably be an easy fix - and you get the satisfaction of fixing it yourself! how cool is that?