[bzar57]

Recently picked up a used 2007 335i AT sedan and I ordered some used cats to replace the catless downpipes the previous owner had on. Upon removing the raspy crap downpipes, I looked into the turbo housing to check for any oil and this is what I found.

I noticed a hose that connects to the back side of the turbo housing that didn't look seated well, could it be entering from here?

Reason I've been doing this swap is because the car has been burning oil and huge plumes of smoke have been coming out of the car when I come to a stop while at stoplights etc. I know it is the smell of oil and it is awful... I'm almost certain it's coming from the exhaust pipes, could this just be because there is no catalytic converter installed? This leak looks pretty bad if it's from the seals itself.

Of course, I've been having some major wastegate rattling that I was planning to adjust, but no sense even trying to do that if the turbo seals are already shot and need replacement. Please advise me what the culprit of this leak may be from. Any help is appreciated.

[limitdown]

The most likely cause is worn journal bearings (ie "seals") in the turbo. The most reliable fix is new OEM turbos.
With older models, other contributors can be worn valve stem seals, PCV valve broken, cracked valve cover.

Clogged and/or leaky oil pipes will cause other problems that can lead to this problem. However, those will not in themselves cause oil to go into that spot.
Your catted downpipes might have already gotten clogged from the oil/smoke.
Your previous catless downpipes might not have been installed properly, so they touched each other or something else, thus causing rattling/rasp.
If any of the most popular 3to5 catless downpipes are installed properly, there would be no rasp, only a deep growl. Although there is nothing technologically special about catless DPs on our platform, fitment is very important. Cheap no-name ebay DPs and also charge pipes are hit and miss. VRSF DPs are cheap and fitment is perfect.

[bzar57]

thanks for the info, I just noticed something from my picture. The wastegate appears closed? How can this be if there is no vacuum and dp are off, car is off? Isn't it normally in the open position when no vacuum is present? Mindboggling

[limitdown]

This is the default wastegate position of my new turbos when they arrived in the mail.
You might need to start saving up or allocating some savings to replace a lot of stuff. These cars are cheap to buy, but very expensive to fix and mod.

[bzar57]

Come to think about it, the pipe gasket on the opposite side of the turbine was pretty shot and I could easily pull off the pipe that was already partially off. That pipe had oil running down it so I'm thinking maybe the leak is higher up on engine someplace

[Jklad]

Catless downpipes do not "cause" smoking. Replacing catless downpipes with cattes dp will not "fix" your smoking issue. It may mask it, but your core issue will still exist. As long as they fit properly, leave the catless pipes on and figure out what's causing the smoking.

[bzar57]

Honestly, I just want it all back to near stock. The previous owner was a first time car owner and from the loud raspyness, I know he didn't install it correctly.

Not to mention, I just want the car to be working normally and legally and I think removing cats are illegal.

Upon reading hours and hours of posts and webpages I've come to the conclusion that the crankcase vent may not be working properly. I'm in the process of ordering a new air feed gasket for the rear of rear turbo, a bracket to hold the plastic crap pipe in place, a new pcv hose as the current one is damaged, and a aftermarket replacement to the PCV valve located in the cover.

I've already removed the downpipes and have no intention of using them at all, I prefer the stock setup more as I had another 335i that I sold last month and it was stock and it was totally enough for me.

I also plan to do wastegate adjustments tomorrow, and just pray that it runs close to what I remember it being like, I wish I didn't sell that other car or pick up this car but it is what it is I just want it to be stock honestly, then I'll sell it.

Hopefully the wastegate adjustments go smoothly as well as the other parts I plan to install..... if anyone else has any info or pointers with all of this, please post here to let me know.

[Jklad]

You bought a modified 335 to turn it back to stock and then sell it?? Interesting....

I just installed catless downpipes with stock exhaust last weekend and wish I would have done it 7 years ago. The car is barely any louder with the dp, stock midpipe cats and stock exhaust, just adds a nice darker tone to the exhaust.

[Chris@VargasTurboTech]

Could be PCV caused, crimped/clogged turbo drain line, or turbos may be shot. Won't know unless you pull it apart but you can check for axial play (in and out in lieu of side to side). There should be very little axial play in the assembly.

Chris

[csmarsha]

what boost level you running?

[007_e350]

Been there, it's the turbo main seal, when it builds boost it doesn't retain oil and starts to burn .. pressurize your intake and you should see oil coming out in turbine housing

[bzar57]

Tomorrow I'm going to replace the gasket holding on the air feed tube behind rear turbo... Seems like this is a common problem that happen to almost all 335i. I know the oil is leaking into there.

As for the boost being ran, I am almost 100% sure the previous owner did not have much clue how to properly set these things. I believe he even used the JB4 installled and ran a meth map without actually using any meth in the system if I recall correctly. Right now, I've set it to the OEM boost either in Map 0 or Map 4 using the JB4. I did a data log on the car and it's still producing a decent amount of boost and actually surpassing the intended target according to the data logs before tapering down.

I installed a OEM intake box I ordered since posting last, changed the bank #2 precat sensor that was trippin (it was used and possibly banged on accident so it didn't fix the code from installing it now waiting on a new one) found a OEM exhaust system from a crashed car and installed that after ripping out all of the previous ridiculously loud aftermarket one that was on there.

Oh yeah on May 30th some dude in a 1968 El Camino wasn't paying attention while driving and nailed my neighbors car and sandwiched it between my car. He didn't even have his headlights on. I ran outside and he dug out. My neighbors car was total loss. Moderate damage to rear quarter panel on my car too, busted taillight & bumper. Car was on jackstands on two wheels and got pushed off to the left by about 5 feet or so. Thank god I wasn't under the car, I was under it just 45 minutes before that happened. Probably would have died. I managed to get his plate but the whole neighborhood came outside and asked me a bunch of questions and I forgot it. :-( Only could clearly remember the first 3 letters. A few days later my wife spotted who she thought may be the car that hit us got his plates and sure enough it had my neighbors paint still on his car. Had the accident all on surveillance anyway, but couldn't see the plate as it was sitting low. Sure enough I live on a small island and it was the guy lol. Not that this has anything to do with the forums here but just thought I should share why I've been absent for so long lol. Wish I had insurance on the car but I didn't as I wasnt driving it yet. Bummer :-( I popped most of it back out and buffed most of the scuffs off already. My other neighbor said he could hardly tell. :-)

Thanks for all the responses everyone, I do appreciate all the feedback from you guys alot. :-) Would have posted sooner but have been super hectic recently as you can see lol. Will post again after my attempts tomorrow.

Originally Posted by bzar57

Tomorrow I'm going to replace the gasket holding on the air feed tube behind rear turbo... Seems like this is a common problem that happen to almost all 335i. I know the oil is leaking into there.

Please don't waste your time doing all this work piecemeal.

The turbos have to come out...end of story. Do all this other work to the inlet, O2 sensor, etc. then. Otherwise you'll end up redoing it all again anyway.

If you want a cheap solution, order some used take offs from RB and just get the job over with:
http://www.ebay.com/itm/230953274413...%3AMEBIDX%3AIT