Smoking XC90 :(

[KemikalGeneral]

Hi all, hope you can help, and this is my first post so I apologise if it's not in a 'preferred' format.

I have a 2003 Volvo XC90 2.9L T6 AWD and for the most part it’s been great.

Over the past year or so I’ve had an issue with it randomly stalling at slow speeds which was progressively getting more frequent. Along with this it did start to hesitate on acceleration at slow speeds and fluctuated at idle, but there have been no other symptoms, no lack of power and no odd noises. When it was running, it ran great!

I whittled the issue down to the PCV system and replaced the PCV oil separator box. As with most of these cases, the small rigid line from the top of the box out to the banjo snapped so I replaced it with a more flexible tube (still quite firm, but has enough flex that it won’t snap).

While getting my hands dirty I also carried out the following:

- Replaced oil and filter
- Replaced fuel filter
- Replaced air filter
- Replaced spark plugs
- Replaced intercooler charge pipe
- Replaced as many vacuum lines as I could find
- Removed, cleaned and refitted throttle body
- Cleaned MAF (with appropriate MAF cleaning spray)

After putting the car back together it runs like a dream. It’s responsive, no hesitation, has a steady idle and has plenty of power… but, the only issue now is that it’s smoking (white, from the exhaust, not the engine).

My initial thought was the head gasket, but the smoke didn’t seem thick enough, plus on the test drive the car ran great. I bought a head gasket tester kit just to be on the safe side (one of those ones that you put in the header tank, add a coloured solution, run the car for 10mins or so and see if it changes colour), which came back negative (it didn’t change colour).

So, I’m at a loss as to what’s causing the smoke. These are my thoughts:

- Aside from the issues mentioned at the start of this post, the car was running great, i.e. no smoke at all
- I find it to be highly coincidental that there were no symptoms of any underlying issues before changing the PCV box, and now it’s smoking like a trooper
- As previously mentioned, the car is running great with no lack of power or anything else that would be cause for concern
- I’m not loosing any fluids, or at least fast enough that I can notice
- My code reader doesn’t find any faults

So as you can see, I’m baffled. The car seemingly has no problems, but is just smoking enough that I don’t want to drive it so it’s just sat on the drive like a sad lonely tank.

Any help with this would br GREATLY appreciated. The car is like a sixth child and is sadly missed


Thanks a bunch.

[SuperHerman]

How many km/miles on the vehicle?

What you describe could be a problem with one or two turbos.

A failing turbo will permit oil into the combustion process hence the smoke. What does your smoke smell like?

[RickHaleParker]

So, I’m at a loss as to what’s causing the smoke. These are my thoughts:

Take a clue from the color and smell of the smoke.

White = Steam.

• If it smells like clean steam it is condensation ( Dew ) vaporizing. Normal on a cold start. Overnight water condenses inside the exhaust system. If it has a sweet smell it is antifreeze.

Blue to Blue-Gray = Oil.

• If it is oil you will smell the oil in the smoke.

Black = Incomplete combustion.

• Will have the smell of raw petrol and/or carbon.

Which is it Condensation, Antifreeze, Oil or Incomplete combustion.

[KemikalGeneral]

How many km/miles on the vehicle?

What you describe could be a problem with one or two turbos.

A failing turbo will permit oil into the combustion process hence the smoke. What does your smoke smell like?

Hi! Apologies for not replying, I didn't get any notifications that someone had replied.

It has around 140K on the clock, and the smoke smells a bit like 'burning', but only if you're standing in or close to it, it's not that strong.

I thought about it being a turbo, but with no previous symptoms (smoking, noises or loss of power), until I changed the PCV box, I found it hard to believe.

Could it go just like that?

[KemikalGeneral]

So, I’m at a loss as to what’s causing the smoke. These are my thoughts:

Take a clue from the color and smell of the smoke.

Hi. It's almost definitely not condensation as it'll pour out for as long as the car is running (half hour at a time).

But, in saying that, there's no blue/grey tint to it either, it's a definite white.

[RickHaleParker]

Hi. It's almost definitely not condensation as it'll pour out for as long as the car is running (half hour at a time).

But, in saying that, there's no blue/grey tint to it either, it's a definite white.

1. Run the engine and let it warm up.
2. Turn off engine.
3. Wire tie a thin White cloth over the tail pipe and run the engine.

Cheesecloth would do well.

The cloth will catch and concentrate whatever is coming out of the tail pipe. Enabling a positive identification.

[SuperHerman]

What type of oil collection did you note on the charge pipes? Normally bank 2 is the problem turbo on the 2.9T.

What you describe sounds an awful lot like a dying turbo - it will get worse and worse.

Has the smoke been a gradual thing or has it slowly been building?