Oil Issues!

[1990e30coupe]

So not even 3k on a fresh rebuild in my 87 325e and still burning major oil on start up.


I have; since the re-build, changed the valve stem seals twice, Checked my ICV, and re routed my crank case ventilation (Bitch tube gone).


I still smoke a lot on start up to the point where I am fouling out brand new NGK spark plugs in two days with major carbon build up after 3 or 4 days if they continue to spark. I have major oil in the intake still and no possible idea on where to go from here besides venting my valve cover to the atmosphere via filter of course. Highly doubt the valve cover ventilation is my issue though as it is a baffled cover. I am getting shitty oil pressure according to my manual gauge I installed, which drops to 10 psi at lights and barely above 20psi on freeway; however on first start up goes above 40psi.


If the new rings were bad I would burn oil throughout driving but I am only burning oil on start up, and about a mile or so after I drive it is when the blues stop.


I am totally at a loss with this engine! With new plugs I cant even drive it 80 miles before I lose a cylinder due to a spark plug.


I have no clue what my next move should be beyond trying to find another motor even though I put so much time and money into this one.

[1990e30coupe]

So some ideas that might be the cause that maybe someone on here could provide some insight on,


I have a straight piped exhaust with a resonator and OBX muffler. Could not enough backpressure be the cause to oil in the intake?


I am running 10w 40 Valvoline oil. I know this is not the most common oil but maybe this might be the issue. Plan on swapping it out to 20w 50 Valvoline.


Is here any vacuum issues that could cause this?


Am I just SOL?

Again since it only smokes on start up the rings have to still be good; therefore, I want to know some insight on anything and everything that could cause oil to go into the intake.


Thanks for your time!

[MrBurgundy]

How did you re route your CCV? It most likely has something to do with that. I'd go back and install the bitch tube then make sure it's 100% sealed.

[jeffnhiscars]

It would help if you define "rebuild".

[1990e30coupe]

It would help if you define "rebuild".

Rebuild as in everything was done except replacing pistons, rods, crank, and cam. Replaced everything else basically except oil pump, valve guides and valves as they were in good shape.


Had head and block shaved, all new bearings, rings, seals/gaskets, timing components, radiator, hoses, new thermostat housing, most all sensors except temp, MAF, ICV. Put manual gauges in for oil pressure and voltage, new O2 sensor, and transmission/diff flush with new fluids. I have done everything in my power to make it reliable up until this oil issue that I cant figure out.

[1990e30coupe]

How did you re route your CCV? It most likely has something to do with that. I'd go back and install the bitch tube then make sure it's 100% sealed.

I have another tube so for now to see if this was the issue I cut one of the tubes down slipped a piece of hose over it with a valve cover breather on the other end. If this helped the situation I was going to put on a catch can kit.


I drove it for half an hour and then parked it for about 20 min, fired it up and smoked quite a bit. I figured I had a lot of oil sitting in the intake; therefore, I drove it a half an hour to work the next day (on highway) and eight hours later fired it up to drive it home, smoked just as bad. I barley made it home 30 miles later as the brand new plugs I put in it were shot.


I do plan on putting the tube back in as I don't think this was the issue; therefore, the only other way for oil to enter the intake is through the valve cover, correct?


When I disconnect the elbow to my intake, I can open the throttle body and watch the oil slowly flow out of the intake.

[E30-325iS]

The bitch tube is there to drain oil from the top of the head.
Sounds like the oil can't drain back to the crankcase and is building up under the valve cover, and from there out of the vent hose on top of the valve cover to the the throttle body.

[uturn]

Is the oil baffle still installed under the valve cover?

[1990e30coupe]

Is the oil baffle still installed under the valve cover?

Yes, Baffle Is still on it.

[1990e30coupe]

The bitch tube is there to drain oil from the top of the head.
Sounds like the oil can't drain back to the crankcase and is building up under the valve cover, and from there out of the vent hose on top of the valve cover to the the throttle body.

It was doing this before removing the tube.

[1990e30coupe]

I figure at this point it is the oil rings. I burnt through almost 2 quarts of oil after driving it a half an hour to work and a half an hour back.

I appreciate all the information you have thrown my way, but it looks like im going to have to re-ring it again. Oil rings just didn't seat right, and there is no way I have two quarts in an hour going through the intake. Only cause for loosing that much is rings for sure.

I used Goetze rings; therefore, I will go genuine this time. I see BavAuto has "Deves" rings anyone know how reliable/good this brand is?

[MrBurgundy]

Do a compression test before you take it apart.

It really seems like oil is being dragged via the CCV.

[1990e30coupe]

Do a compression test before you take it apart.

It really seems like oil is being dragged via the CCV.

Agree, since I do have quite a bit of oil in the intake, but I have temporarily re-routed the CCV system to see if the issue gets any better and it did not.


A compression test wont tell me if the oil rings are bad, and it does run so no issue with compression rings. It was simply the oil rings that did not seat. I can do a compression test but it is not going to tell me anything about my oil issue that I know of.

[1990e30coupe]

The bitch tube is there to drain oil from the top of the head.
Sounds like the oil can't drain back to the crankcase and is building up under the valve cover, and from there out of the vent hose on top of the valve cover to the the throttle body.

This was going on before I removed the tube to see if high crank case pressure was an issue, possibly throwing oil up through it. I had planned on putting a new tube back in just wanted to see if this was a cause.


So when the tube was in/ will be back in, what was/is causing me to have major amounts of oil in the intake?


I am going through a lot of oil and because I just put my second set of valve stem seals on and it didn't help it has to be that the oil rings did not seat, but this still doesn't explain the oil in the intake.

[E30-325iS]

I know you said it was doing this before, but before throwing more parts at it you might as well try a few simple things first.
Remove the intake manifold and make sure the oil drain hole is not blocked and that oil can drain freely from the head to the crankcase through the bitchtube.
After that you could try routing the hose from the top of the valve cover via a catch can to see how much collects in there.
Make sure the valve stem seals are correct for your valve stem diameter.
Other than that, assuming that you checked all clearances, etc. during your rebuild and everything was ok, then you might have a crack somewhere thats letting oil into the cylinder.
I'm not a mechanic so take the above with a pinch of salt and get a professional opinion.