Inlet ducting clogged
 

Just pulled the elbow between the throttle body and the inlet manifold, and as expected (same on my previous xc90) it's chocker with black oily sludge.
No doubt the throttle body will be too, and the inlet manifold.
And.....the ducting to and from the intercooler, the intercooler itself....
Is there a method of cleaning all of this, and any tips on reducing/preventing the build up?

It's "only" EGR to head that cokes up. I just regard it as a horrible job that you do every 150-200k and change the swirl flaps at the same time. Oven cleaner and solvents just made it harder to move for me.

no real way of stopping this it just one of the maintenance jobs that need doing before it makes a fault that shows throttle body /egr ect

Thanks guys. Yes, strangely I pulled the pipe off the upwind end of the throttle body thing (from the intercooler) and that was quite (relatively) clean.
I guess a can of carb cleaner and a thorough blathering is the approach!

Clean and EGR (software) delete worked for me. Nice and clean 40k later, just they was it was designed.

There's no way to stop it.

Get yourself some carb cleaner and give it a good scrub. Its a very messy job though, so make sure you cover your floor and wear gloves if you can. I know lots of people don't like wearing them, but if you don't, you'll be scrubbing your hands and the pipework too. :tounge_smile:

Thanks dambat. Are swirl flaps expensive to change?

The swirl flaps themselves aren't very expensive. you can buy the whole kit with gasket and seals for about £60. The problem is whether the injectors come out freely or not. A siezed injector can cause a whole world of pain and that pain comes at a price.

LOL I'm a risk taker, and prices in Australia/shipping from UK are high, so I used an Aliexpress swirl flap kit for $A40 (about the cost of a genuine swirl flap linkage) like this:
https://www.aliexpress.com/item/1005005262067417.html

It seemed OK quality, and OEM swirl flaps are not great anyway....

I cleaned everything, including the injector seats with dowel and some very fine sandpaper glued to the end of the dowel, and reused everything else, including the clamps, which I bent back to provide tension.

Apparently injector seizure is rare in D5s and mine came out easily. Kept them in order though.

Everything has been fine - no diesel, injector seat, or oil leaks, and swirl flaps are now functioning. Runs a bit smoother, but not a massive change to performance.