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.

[NMB]

Can you clarify how bad the white smoke is and when does it smoke? Cold starts? Hard acceleration? Deceleration? All the time?

[KemikalGeneral]

Hi NMB,

It's hard to say.

There's enough smoke that it's causing me not to drive it, but not enough that would make me pull over if driving.

There's enough that the neighbours would ask if everything is ok if they saw it, but not enough that someone would call the fire brigade.

I can see through it, if that helps, and it smokes constantly, more under acceleration.


Thanks

[NMB]

I would start with going back over the vacuum lines to ensure that each one is correctly installed and there are no leaks. I would also check the intake system and recheck the seals of the throttle body through to the Intercooler charge pipe.

Logic dictates that if it wasn't doing this before then it has started because you have overlooked something/incorrectly installed something with the work you have done?

Alternatively, as the car is not using any fluids, does not lack power and does not report any codes on VIDA then it may be that the car just needs a good drive to clear out the excess gunk from the induction system post cleaning? - I assume that this was pretty disgusting with oil, carbon and crap when you cleaned?

[gmonag]

Agree. Sounds like a charge pipe/intercooler leak.

[Music2ears]

I tried everything I could think of that could be causing the smoking and after quite some time I bit the bullet and chopped it into my local-ish Indy Volvo specialist, who in about three seconds said, that’s an intercooler failure.
About £300/350 and a couple of hours later the kit was fitted and the smoked had entirely disappeared. Even when giving it a bit of welly!
I was quite amazed that this would make this kind of problem, without affecting the performance at all.

Let us know how you get on! 👍

[NMB]

Glad its sorted - well done.