[MachWon]

07 335i, chassis has ~127k, motor has ~71k. Turbos have 3k on them. The motor came with turbos, and upon installing the car smoked coming to a stop and smelled like oil. Took it back to the shop and they diagnosed as blown turbo. Ordered 2 new turbos, installed and the car didn't smoke for 2.5-3k miles. I had to put a half quart of oil in it about 1k miles ago, didn't really think much about it. Then, friday night, had to put the other half quart in it. Got the "oil at minimum" warning on my dash both times. I thought it HAD to be a leak somewhere, but last night I got on it in 1st then came to a redlight, and boom. Smelled burnt oil. I don't believe the car is smoking as multiple people have told me it isn't, but definitely smelled burnt oil. The car had a new valve cover and valve cover gasket put on when the motor was swapped.

I don't know what to do at this point. The turbos have a 2 year warranty, but it's still another 1,000 for labor to get them replaced AGAIN (done at an indy shop). Can't really cut my losses on the car as I am way too deep, which I was fine with as long as the car was healthy (I absolutely love it).

Is there anything else it could be besides turbos? I noticed that it seems to lose oil faster when the oil is hot, over the halfway mark. Should I get a lower temp oil thermostat and try it? Let me know what you guys think.

[Chris@BoostConcepts]

Need to determine if it is pcv related. Turbo related or just worn and getting past the rings. Discovering the culprit of using oil is the very first step before swapping out parts blindly.

Leak down test and compression test you could do yourself or shouldn't be too bad from an Indy shop.

Ho over the pcv system really well. Check catch can, maybe pull intake to see how ports look. Etc.. Identify it through inspection procedures first though before throwing new parts at it or you may be able astng more money then you have too.

[Pbforlife254]

Having the same problem with oil consumption. Used about 1/4 of a quart in 1,200 miles of city driving. Go on a little 350 mile round trip today and right once I got going on the highway oil level dropped to 1/2 quart used. Then on the way back it dropped again. Used about 3/4 of a quart in 1500 miles give or take. Recently replaced valve cover, oil filter housing. No visable oil on the ground or anywhere I can see. Not sure what is leaking or if my car just eats oil.

[limitdown]

I concur with lcvette.
Check every piece of the PCV system first.
Another place to check is the turbos' feed and drain pipes. If they are clogged or kinked, oil will get backed up and cause issues.
If you can get the car on a ramp, check if the oil pan gasket is leaking.
It would really suck if the compression test and leak down show cylinder issues, since you just swapped motors.

[MachWon]

Oil pan gasket is new. Motor was compression tested before it went in and passed. I've put the car on E60 twice at ~19 psi but surely a couple tanks worth of higher boost wouldn't blow new turbos that quickly. The car only smells if I get on it hard.

To make it clear:
4k miles since new motor
3k miles on turbos
4k miles on VCG, OPG, both main seals
No visible oil leaks, block is bone dry. Definitely burning in the exhaust

Now that I think about it, I'm not sure it's the turbos. I had to add oil after about 1k miles... ON BRAND NEW TURBOS. It doesn't make any sense. I put a new valve cover on the car specifically to rule out a PCV issue. I honestly think it would be wiser in the long run at this point to put the on3 single kit on the car. At least if/when the turbo goes I won't have to pay 1k to have it taken off and warrantied.

[cstmx_ryder]

So this is interesting......I can't say that I'm experience the same things. BUT, in the past and recently, my iDrive gave me an 'oil at minimum level' warning, ironically right after getting on it, and I mean, getting on it. I've noticed this for a while now, and still couldn't figure out the culprit.

Please keep this thread updated as I'm curious as well.

TIA

[MachWon]

I haven't had a screen pop up on the iDrive, just the yellow oil can on the dash itself. And I'm not getting a warning after getting on it, I have just only noticed oil smell and slight smoke after getting on it. Never when driving normal.

[j1gilles]

Exhaust valve guides/seals.

[MachWon]

I have a lot of other stuff to rule out before something that serious.

It's also worth noting that there is a coating of oil on the vent port on the DV's (they're set up to VTA), as well as on my front DCI where it faces the DV. Seems like my DV's are blowing out some oil when they vent. I'm really hoping it's a PCV issue because it can be fixed relatively easily.

What else do I need to check on the PCV system if the valve cover is new? I do not run a catch can setup, everything is stock.

Originally Posted by MachWon

I have a lot of other stuff to rule out before something that serious.

Yeah exactly; you should have already ruled that out before the new turbos went on, but my guess is you didn't

[MachWon]

I didn't rule anything out. The car smoked on the old motor. New motor got put in and it smoked the exact same way, coming to a stop 5 minutes after I picked the car up. Drove it back, got told to drive it for a week and see if it clears up, it didn't. Take it back, shop diagnoses it with blown turbo, replaced with brand new ones. After new turbos the smoke cleared up 100% until now. Why would it do that if it was the valve guides/seals?

[MachWon]

Also, the car isn't smoking in boost. I've actually asked people that are behind me if they've seen it smoke, and everyone has said no smoke whatsoever. It doesn't smoke on startup either. I had a friend Rev the car hard a couple times yesterday while I watched the exhaust, just a hint of smoke when the car revved down and a little burnt oil smell.

[j1gilles]

Originally Posted by MachWon

Also, the car isn't smoking in boost. I've actually asked people that are behind me if they've seen it smoke, and everyone has said no smoke whatsoever. It doesn't smoke on startup either. I had a friend Rev the car hard a couple times yesterday while I watched the exhaust, just a hint of smoke when the car revved down and a little burnt oil smell.

Typically cars with bad valve guides don't smoke under boost.

[cstmx_ryder]

Is the exhaust valve guide/seal easy to replace? Not sure of the exact location either, please elaborate....

TIA

[j1gilles]

Originally Posted by cstmx_ryder

Is the exhaust valve guide/seal easy to replace? Not sure of the exact location either, please elaborate....

TIA

There are a couple of DIY's floating around. If you are mechanically incline it isn't too bad.

[ferocity02]

Originally Posted by j1gilles

There are a couple of DIY's floating around. If you are mechanically incline it isn't too bad.

Can you post these DIY's? I can't find any for the N54.

Looks like you need some special tools for the cam timing, and probably to compress the springs. Should also replace the cam ledge bearings while you're in there.

[blaster3500]

We're the turbos rebuilt or new turbos from the dealer?

[j1gilles]

Originally Posted by ferocity02

Can you post these DIY's? I can't find any for the N54.

Looks like you need some special tools for the cam timing, and probably to compress the springs. Should also replace the cam ledge bearings while you're in there.

I'll look for them... You can rent the tools