HELP! Heavy white smoke out tailpipes – smells like gas (not coolant)

[thesalboy]

Thanks for all the posts.

I edited the prior post of video links to provide context.

The smoke is definitely not water vapor. I am fairly certain it’s fuel vapor. When I ran it for 15 minutes, the exhaust tips were wet with what smelled like gas.

The oil separator is brand new – purchased from The BMW Part Store and appeared to be Genuine BMW. While pulling the intake, the old oil separator came right out in my hand after I undid the two bolts that hold it in. The larger of the two hoses that come from the metal pipe at the back of the passenger side of the motor, which connects to the bottom of the oil separator, had disintegrated – there was a small amount of burnt oil on the coolant crossover pipe nearby. The smaller of those hoses – the one that goes underneath the intake manifold and attaches to a port on the inside of the EGR (which is also brand new) – had also disintegrated. I replaced both hoses with new.

I’ve started the car maybe 6 times. In the video, the car had not run for a day, and as before the smoke starts out light but quickly gets heavy. When I’ve restarted the car within a short period of time, it smoked heavily right away. The heaviest was after I tested the injector harness with the noid light. I hadn’t disabled the fuel pump. That’s part of what made me think injectors were stuck open. I believe this means there is a ton of fuel dumping into the exhaust. When the car sits it evaporates.

The valve cover gaskets are brand new. There was oil in the passenger side plugs. I sopped it up before changing plugs. Pretty sure the car has run enough to burn off any oil that may have gotten into the combustion chamber.

I also replaced all coolant hoses. There is no coolant leaking anywhere. To change the valley pan I removed the coolant crossover pipe at the rear of the motor. Used new gaskets on reinstall.

It is lower on oil than where I remember it being, so maybe it is sucking too much oil into the intake. I’ll research oil separator issues – “found” this video suggesting it might be the problem: https://www.youtube.com/watch?v=s8irMmWvWfw. I’ll also pull the oil fill cap – I assume the expected result is suction and rough running. I’ll also pull a few plugs to see what they look like.

[thesalboy]

#1 plug looks too clean to me to think it’s burning that much oil.



I pulled oil fill cap while running – not sure if I was being punked. Oil squirted everywhere. Engine idle dropped, and picked back up when I replaced the cap. I think I heard sucking but was more focused on the squirting oil.


In researching oil separator issues, I see that my oil separator hoses may be reversed. I reinstalled them as they were before I started work (“before” pic below) but this post says they were wrong: 2001 X5 4.4i - CCV/Oil separator confused - Bimmerfest - BMW Forums. I swapped the hoses according to that post, and when I started it, I had high hopes. It took longer to start smoking, but within a few minutes it was back to the same behavior.

[bcredliner]

Sorry I wasn't clear, you don't have to completely remove the oil fill cap just pull it up enough to feel how much vacuum there is. There should be some but it should not be that much.

[thesalboy]

Got it thanks.

Well, RealOEM shows the oil separator hoses connected the way mine were before I started! RealOEM.com * BMW E53 X5 4.4i Crankcase-Ventilation/oil separator

[bcredliner]

realoem is the way to go.

[thesalboy]

Agreed, and it makes sense. The hose should go from the valve cover to the bottom port of the oil separator, at which point the centrifuge separates oil sending it down, while the vapor goes up and out the top.

I bypassed the CCV by pulling the top hose off the oil separator putting a stopper in it, and the heavy smoke is gone. Must be bad.

[thesalboy]

For CCV bypass, I capped the hose from the valve cover with a breather, but it proved too restrictive, overpressurizing the crankcase and pushing oil first out the drain plug (!) and after that was tightened, out the dipstick. It's now venting straight to atmosphere. Drives fine, no codes, only occasional smoke which I assume is from residual oil in the intake manifold.

I've seen some posts suggesting that aftermarket CCVs go bad. I ordered from The BMW Part Store and understood everything they sold was genuine, but I'm checking.

[upallnight]

Did the replacement part have the BMW Roundel on it? Not saying that fake part wouldn't have the roundel, but if the the fake part was founded to be counterfeit during custom, the shipment could be impounded, whereas a cheap part without the roundel would not be impounded at custom.

[jsoto]

I've used BMW Part Store for years....all OE in my experience

[Omerta]

Do you have an OBD reader to check the Air Fuel Ratio? Was there any QC documentation from Mr. Injector?