hello I have a problem with my allroad. every now and then (about 2 times during a cold season.) the car will smoke after startup very thick white smoke to the point I cannot see anything behind me while driving so I take my infiniti to work when it happens. I always warm up the car for at least three minutes before driving in cold temperatures.

here is some background I use 5w30 amsoil (I think I should go thicker maybe it will help)
I do have a check engine light on apparently the pass warmup cat is no longer doing its job (its not the sensor its the cat) but I dont see how the car would smoke that bad.

the car does not miss or run funny.

like I said it is not a problem that I can recreate on demand because if I come back and start the car 15 minutes later the car will be fine and will not smoke. (when I see that the car is about to smoke I let it warm up longer because of the cold weather but it does not go away.

The smoke is white which seems like a headgasket maybe but Im not sure, the smoke smells like a top engine cleaner treatment (if you ever did one you know what I mean its a weird smell.)

ive think Ive narrowed it down to a headgasket or a new cat but havent did anything to be sure. If you have a suggestion I would be happy to hear it thanks.

 

Just had this happen to me after a -20f cold spell. Seems any moisture trapped in the valves and hoses related to the crankcase ventilation can freeze up and cause the oil to back up and get into the exhaust. The pressure build up was so bad it probably blew a cam seal and i observed oil forced out of the dip stick. I let the car sit and "melt" under it's own engine heat and everything returned to normal.Thought I'd blown and engine there for a minute

 

true this seems to be the consensus I did a little more digging and i believe it is a check valve in the system is stuck due to condensation but it would be nice to know which one so I can replace it. I no longer have the problem but it sure is embarrassing when it does happen and dangerous for folks behind me so I dont drive it when it does. but like you said when I shut it down and let the radiant heat from the motor warm the hoses the car will run fine after ten minutes with the motor shut down. If I ever find it I will post some pics and part numbers. I believe this is just a 2.7t problem.

 

Mines going in today to have the valve and assocoiated hoses replaced. I'll ask my mechanic what parts are included

 

I just had this happen to me yesterday. Right after leaving for work (car fully warmed while I drank coffee), I got on the highway and noticed a lot of white stuff behind me. It looked like I had failed to clean the snow off the car before leaving, only the car was clean, so that wasn't it. That's the point where I got that cold sinking feeling in my wallet. I let off the gas, the smoke went away. I gave it gas, and huge clouds of white smoke.

So, instead of going to work I spent the day (about six hours) researching this issue. Once I got past all of the "you blew your turbo, get ready to pay 8 grand", or "blown headgasket, bend over and grab your ankles" threads, I finally came across one that mentioned the PCV valve sticking due to ice. So I begin to have some hope at last.

Took the car for another drive, and dammit all if it wasn't still smoking! Also, it felt like it was really down on power (crap! another symptom of a blown turbo!). However, after about a mile the smoke went away and the power came back. Probably just had to blow out whatever oil had been forced into the system while the valve was plugged.

Drove the car to work today, no issues. Planning to replace the PCV valve and vacuum pump (cheap and easy from what I've read), just to avoid the chance of future issues.

Now, considering how often this seems to happen when it is cold outside (it was 4 degrees when I had the issue), I'm wondering how many people have been told they need a turbo, engine, TC or tranny, when it was simply a sticky PCV valve. But of course, if a mechanic did the job and got to the turbos only to find that they were okay, they would be sure to tell you all about it and not charge you anything. Right? lol.

 

thanks for the post and the info (elaborating on the actual part that fails is what I was getting at) keep us updated after you replace the items and if it helped or not (even though it doesnt happen often). Ill look into my pcv when it gets warmer outside.

 

Hello all, I just had this occurrence take place.
A couple of days passed and I was ready to believe I needed new turbos.
Was somewhat warmer today and I thought heck, I'll just start her up and see.
The smoking is gone except for some of the residual oil in the exhaust system from that ugly morning.

Just wondering if anyone has figured out a possible cure for the problem?
Thank you for any help.