VNT Turbo De-Coke

Good stuff!
How long did the whole process take you?

A couple of hours for dis-assembly, cleaning and re-assembly, most of which is waiting time. It takes longer to remove it from an A2. Removal from a Lupo is much easier - much more accessible!

RAB

Just curious, did you see an improvement in the performance at all and/or is it purely pre-preventative to keep the turbo going for longer?

thanks

It's mainly an increase in economy but was also done recently to prevent a repeat of the VNT jamming in the max position, which possibly lead to the write-off of a Lupo 3L turbo during an MOT test run, resulting in the shaft breaking! Of course the miscreant stated that he'd driven my car carefully!

RAB

In terms of risk/effort vs outcome how does this compare to using a chemical cleaner such as Innotec Turbo Cleaner?
How much needs to be removed to get at the turbo?

If you use Innotec there's more than a slim chance that it will contact the bearings. Turbo seals only work when the turbo is rotating which is why they are always mounted horizontally. My advice would be DON'T!

Remove EGR cooler (you don't need to remove the hoses), remove the inlet manifold and then the turbo. The only difficult part is a bolt which holds the turbo bracket to the block - you can only reach it from below with a ring spanner. Use a nut splitter if you have a problem with turbo to exhaust manifold nuts and use hot bolt paste to avoid the problem next time.

RAB

Thanks for the tips.
I imagine mine will be disgusting inside with the very cold winters and a fair few short trips.
How often have you cleaned the turbo on your "fleet"?
Do you reuse the old bolts or get new ones?

So from the above there is no need to remove any hoses?

Does cleaning the turbo smooth out the curve at low speeds. Mine is a little rough on pickup now and then.

John

I've done each one once but the A2 is due for a cambelt change later this year, so will probably be done again. Three of the bolts are specials with rolled-on stepped washers, so difficult to replace. You may find some kits somewhere. There are no gaskets to replace apart from the one on the oil return flange, which you can buy from Audi.

I didn't say there's no need to remove any hoses, only that the coolant hoses to the EGR cooler don't need to be removed. Otherwise all the hoses connected to the turbo have to be removed, of course.

I haven't noticed much difference in performance (there's not much performance with a 1.2 anyway!). It will affect economy though. But if you leave it too long (and it needs doing), the VNT will jam or it will keep going into limp mode.

RAB

I should make it clear that 'gaskets' refers to those on the turbo only. Otherwise, you will need two gaskets for the EGR cooler, one for the inlet manifold and one for the turbo/exhaust, plus eight nuts of two different types. There's no gasket between the turbo and the exhaust manifold. That's for a 1.2.

RAB

I think at 200k it's worth doing this to our Passat
The inlet manifold and egr valve are known for getting grotty and clogged on those so they're coming off anyway, I'm going to try something like this http://www.ebay.co.uk/itm/Vapour-Blasting-Inlet-Manifold-cosworth-Westfield-Kit-Porsche-911-944-356-Car-/171043007423?_trksid=p2047675.l2557&ssPageName=STRK%3AMEWAX%3AIT&nma=true&si=tGxF0E6%252Bu%252FK6KZdVhYa9PYYk8cQ%253D&orig_cvip=true&rt=nc to get the insides cleaned out.

It's curious that 90 owners seem to get lower mpgs than 75 owners, yet sticky vanes (acting like fixed vanes) lower the mpg

The two sides of a diesel; happy to trundle along at low revs, needs exercising through the revs to keep it clean. I wonder if I could justify a trip to Italy to tune it?

I have found a longer term solution to this now. Even using oven cleaner after dismantling was not entirely satisfactory as the VNT mechanism is not very accessible, leaving a slightly 'notchy' feel to the mechanism. So I bought a heated ultrasonic cleaner; water and a handful of washing soda and it's as good as new. Not the whole turbo, just the exhaust end with the VNT mechanism! Don't waste your time with Innotec.

RAB

Are the gaskets and washers required usually a stocked item?
My car kept going into limp home mode on a motorway drive today after being in storage for six months. Just before going into storage the temperature sensor was not working and so the car took over 2 hours to reach 90c. I suspect this caused far more fuel than normal to be pumped in and so a fair amount of extra soot. On this basis I suspect a deep clean of the turbo may be the best option.

Is there any way to free the vanes/mechanism without disassembly?

In removing the turbo do you need to crawl around under the car? From the instructions I have seen it should be accessible from the top (except the bottom nut) and do you need to take the small catalytic converter out before removing the turbo?

I take it from your guide that removing the last torx screws and completely disassembling the vnt mechanism such as on Kev's blog is unnecessary?

I guess also that driving a constantly limp mode car is not a good option. It will probably end in a lot more damage.

Thanks!

RAB said:

I have found a longer term solution to this now. Even using oven cleaner after dismantling was not entirely satisfactory as the VNT mechanism is not very accessible, leaving a slightly 'notchy' feel to the mechanism. So I bought a heated ultrasonic cleaner; water and a handful of washing soda and it's as good as new. Not the whole turbo, just the exhaust end with the VNT mechanism! Don't waste your time with Innotec.

RAB

Click to expand...

Rab do you still have this car? If so how has the fix lasted?

How long the fix lasts depends on how you use the car. The more short journeys you do generally, the more frequent the requirement for cleaning. I only largely use my Tdi's for longer journeys; for the shorter ones I have an E-Up! Frequent manual movement of the VNT mechanism might help.

RAB

Has anyone tried Terraclean ? I'm generally pretty skeptical of those sort of services, but if it works and the cost is about £90 then given the disruption of taking all this apart, new gaskets etc., etc., then it may be a viable option. The real question is, would it clean this crud out of the turbo, or just the soft/oily deposits?

My car has been Terracleaned and it made an ever so slight difference on acceleration and economy. Sadly it does not clean out the turbo and the only way to do that is a strip down I,m afraid.