[humbertob]

Hello there, here it's the issue on my son's car, it's a 2011 335i with the n55 engine. Replaced recently the oil pan gasket, the oil filter housing gasket and the valve cover gasket, and 3 days ago the car started dripping oil directly into the bottle shape part of the catalytic converter, I see smoke coming from that area due to the oil being burned by the catalytic converter but I have no clue where the oil is coming from, I'm really confused and frustrated any one with the same issue or symptoms or a possible diagnostic/remedy? Thanks in advance !

[320IN54]

Is your car smoking from the exhaust pipes? If so it could be that your turbo seals are leaking if oil is actually dropping into your cars cats.

[mweisdorfer]

Originally Posted by GotPwned

Is your car smoking from the exhaust pipes? If so it could be that your turbo seals are leaking if oil is actually dropping into your cars cats.

I'd second the idea that I'd could be the seals of the oil lines on the turbos.

It could also be the back side of the valve cover gasket too.

Last, check the crank case valve on top of the engine near the PVC. It should be replaced every 50k. If it's failing, it too could be leaking oil on the exhaust.

[robthewrench]

Was the work done by you or a mechanic? If a mechanic, take it back to them. Most likely it something they either replaced or touched during the repair work. Repair work is typically warrantied for 12 months 12K miles.

As note, be very careful about this leak. If the leak is substantial, the spilled oil can ignite on the exhaust. I've had this happen on cars and if you don't have an extinguisher handy, you could burn down the car and the house if the car is in the garage.

The oil is most likely coming from somewhere up higher on the engine block and then dripping down to the cat. I would not suspect the turbo (1 for the N55) because the turbo is usually hot enough to smoke the oil right there at the turbo. A turbo leak cooks the oil before it can drip anywhere else.

[humbertob]

Work was performed by myself, really easy diy, very involved but nothing but removing bolts and cables, the valve cover was torqued at 8.5Nm and gasket is seated right between the valve cover and the engine block. I just called my expert BMW mechanic in San Antonio TX (I live in Laredo, 165 miles away from him) and he told me that the culprit is the valve cover gasket, no doubt. May be I'll need to replace the entire valve cover gasket again with a BMW OEM and not Victor Reinz one.

[Faredo]

Into? or ONto? For some reason i think you mean ON. If thats the case I would look at the valve cover having a crack. It can drip on the the passenger rear of the valve cover which is over your catalytic converter.

[litxus]

Not sure if N55 valve covers crack, but my N54 valve cover cracked and I had to get new one. It was somewhere close to oil fill cap and then going down left (looking from front), you could barely see it.

[feuer]

It is from the VCG.

[humbertob]

I just ordered a BMW original valve cover gasket and will replace it again : hope I don't have a cracked valve cover, brand new part is more than $500

[mweisdorfer]

Originally Posted by humbertob

I just ordered a BMW original valve cover gasket and will replace it again : hope I don't have a cracked valve cover, brand new part is more than $500

I have seen new valve covers for $350-400.

https://www.ecstuning.com/b-genuine-...SABEgLsuPD_BwE

[humbertob]

Lately this car has been a gold pot. In the last 2 months: Radiator $300, Oil pan gasket $1200, Oil filter housing gasket $50, Ignition Coils $240 and now the valve cover. All of these costs are DIY, just the oil pan gasket was replaced by a competitive shop out of town.

[humbertob]

Second valve cover gasket this week and the car still leaking oil from somewhere and directly onto the catalytic converter, I'm getting nuts here but now I can dissasamble all the components over the valve cover with my eyes closed ! This time the valve cover is OEM BMW and still the same issue, any advice guys ?

[feuer]

Being BMW part by itself doesn't guarantee it has been installed properly. Find the leak.

[humbertob]

I'm suspecting a broken head bolt, is this a common issue on the n55 engine? Or am I just being so negative here? I'll disassamble the whole valve cover tonight and let you know !

[buster84]

I recently had the same problem with an oil leaking on the cats. Took my 09 e93 into bmw under warranty and it turns out the oil was leaking at the rear of the valve cover and from the turbos. The valve cover also had a crack in it. Then I also had another oil leak at the oil filter. I also had Watergate rattle. Right now it's in the shop getting repaired, lots of new parts as well as new turbos. This is the one time I'm thankful to have had the extended warranty.

Hopefully you'll get it all figured out, but it's possible that your valve cover is also cracked. I'd also check your turbo oil line to make sure the gaskets arnt leaking.

[humbertob]

Thanks buster84, in the case of the n55 the turbos are not in that area and it's a single turbo on this engine, I think that I got a cracked valve cover, I'll remove everything tomorrow and visual check the valve cover for cracks, Thanks pal !

[humbertob]

For the third time this week, I removed the valve cover from my son's car, decided to remove the aluminum tray that catches the oil when leaking, the one that holds a sensor in place and it's used to route the O2 sensor cables, just cleaned this tray with degreaser and after driving the car for 25min seems that the smoke of oil burning is gone, I'll be monitoring the fix and keep you all posted !!! Thanks for all your support guys !

[humbertob]

Confirmed no more oil burning at the cat !!!

[Faredo]

So you ether had residual oil dripping after your VCG changes, or you moved the leak you still have.

[humbertob]

No more leaks at all the culprit was the residual oil after my vcg !

[buster84]

That's good to hear that its fixed.

[beetle6986]

Originally Posted by humbertob

No more leaks at all the culprit was the residual oil after my vcg !

Wonder if I have the same issue. Oil is still burning off occasionally after the new gasket was installed. I've run it for a half hour now.