Excessive white smoke after turbo change?

Tiny
DAVIDCRISTIANJAVA
  • MEMBER
  • 2007 AUDI A4
  • 2.0L
  • 4 CYL
  • TURBO
  • 2WD
  • MANUAL
  • 415,000 MILES
Da, știu. ÎțI fac un rezumat scurt și clar în engleză, pe care îl poți folosi direct:


---

Car details:
Audi A4 B7, 2007, 2.0 TDI, engine code BPW.
EGR and DPF have been deleted by the previous owner.

Problem description:

After replacing the turbo, the car produces a lot of white smoke at idle, both from the exhaust and from under the engine under.

The check engine light and glow plug light (flashing) come on intermittently, mostly under load around 2000 rpm, but sometimes not at all.

When the glow plug light is on and I turn off the engine, it shuts down very abruptly, like it “dies.”

These issues existed even before the turbo was replaced. But the smoke appeared only after. The previous mechanic changed some filters and the necessary gaskets.

Drove about 1000 km since the new turbo was installed and people stop near me and ask me if I'm aware of the smoke and if my car is going to start on fire.
Saturday, August 30th, 2025 AT 4:37 AM

3 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
When the old turbo failed, it may have dumped oil into the intercooler and exhaust. After installing the new turbo, that oil can take hundreds of km to fully burn off. Can I ask what the smoke smells like? If it is sweet and pungent it is coolant which would indicate a blown head gasket. If is smells like engine oil there is oil left in the turbo air tubes which need to be cleaned out, if the oil return line is clogged for the new turbo it is forcing oil into the engine which is dangerous because the diesel engine can ignite the oil and cause engine runaway. I would use this guide to check for a blown head gasket if the smell is sweet/pungent.

https://www.2carpros.com/articles/head-gasket-blown-test

Please go over this guide and get back to us. Please upload pictures or videos in your response of any problems
Was this
answer
helpful?
Yes
No
Saturday, August 30th, 2025 AT 6:58 PM
Tiny
DAVIDCRISTIANJAVA
  • MEMBER
  • 2 POSTS
Hi, just to update you: the coolant level is not dropping at all, and all the pipes were cleaned with brake cleaner as far as I understood from the mechanic. The smoke has a somewhat pungent smell, but I can’t really describe it well. I went back to the same mechanic and after checking again he said the turbo is installed correctly and he thinks the issue might be from a glow plug that needs replacing. However, I find it strange because the car did not produce any smoke at all before I changed the turbo.
Video (Click to make bigger)
Thumb
Was this
answer
helpful?
Yes
No
Sunday, August 31st, 2025 AT 2:38 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
It sure looks like oil is burning, I can see the smoke at both placed, under the hood and out the exhaust pipe. Since the engine did not smoke before the repair I would say the oil drain tube is blocked or you have a defective turbo. I don't think it is coolant since you have not lost any, I would get the car on a rack so you can look underneath using a flashlight to see if the turbo drain is leaking onto the exhaust which will tell you for sure this is the problem. Thanks for the video it helps a lot. Here is the oil pressure and return line in the daigrams below. Check out the images (below). Let us know how it goes
Image (Click to make bigger)
Thumb
Was this
answer
helpful?
Yes
No
Sunday, August 31st, 2025 AT 9:47 AM

Please login or register to post a reply.

Related White Smoke Content

White Smoke
GUIDE
White Smoke
There are different levels of white smoke/steam which could be a normal occurrence. A small amount of water is produced as a normal bi product of the combustion process and...
VIEW MORE