Porsche 911UK Forum

Welcome to the @Porsche911UK website. Register a free account today to become a member! Sign up is quick and easy, then you can view, participate in topics and posts across the site that covers all things Porsche.

Already registered and looking to recovery your account, select 'login in' and then the 'forget your password' option.

Sorting sticky vanes in a TDi

GP41

Well-known member
Joined
19 Oct 2014
Messages
476
Hi all,

Just had our Audi A4 TDi go into limp mode today. Reading around the topic all the symptoms suggest the turbo vanes are sticking causing an overboost that then puts the car into limp mode. The thing is, the two most commonly suggested solutions are to pump Mr Muscle oven cleaner (i.e. NaOH) into your turbo body to remove carbon deposits, being sure not to get it into the wrong place as it starts to dissolve aluminium parts and can lead to a build up of Hydrogen :eek:, or use a fuel additive like Forte.

Anybody had any experience of these techniques? Sounds like Mr Muscle, if done right, would be very effective if a bit fiddly, whereas an additive is really simple, perhaps a bit more costly, though to be honest compared to the cost of a new turbo, both are massively cheaper!

Any advice appreciated.
 
:weed:

I know it wasn't Porsche related but I thought I'd have had some sort of response, even if it was rude. :p

If anyone's interested I've decided to add some Forte diesel turbo cleaner. Couldn't quite bring myself to squirt oven cleaner in...
 
I had this on a Passat. Recon turbo seems to be the long term fix.

MC
 
If you turn the engine off and then back on does it reset the ECU ie takes it out of limp mode or is it permanently in limp :dont know:

If the former it could be you have a vacuum leak in a pipe/hose connection to the intercooler as I've never heard of sticking vanes? Could be the EGR valve?

What's the mileage and what's your driving pattern ie does it regularly get revved through the full rev range under hard acceleration to clear the crap out? Has it got a DPF - in which case and you use it mainly on short city type journeys expect some problems :what:

This site may help but it leans to an air leak as the main cause. VAGCOM may assist?

http://www.myturbodiesel.com/wiki/l...roubleshooting-vw-seat-skoda-audi-tdi-engine/

Good luck :thumb:
 
They do get sticking vanes. Our car was fine on very light load but would go in to limp if you put your foot down, reset on key-off. We had only just bought the car and the dealer paid for a recon turbo. No problems since.

MC
 
You can get turbo cleaning fluid some can spray in situ others take turbo off and seal with gaskets and fill with fluid
Long term replace turbo give Fast Turbos a ring on 01536601020 local specialist in VW AUDI use them a lot
Good luck
 
Thanks for the suggestions.

The switch off and on does take it out of limp mode. The car's a B6 A4 1.9 TDi with about 120k miles on. Over the past couple of years it's started doing a lot more shorter journeys and only gets driven hard when I get chance to drive it :) . Otherwise it does a lot of local pottering and as I understand it, crucially, probably doesn't get fully warmed up.

I'll try cleaning it out and if I get chance get it plugged into a VAGCOM to see what the error codes are. If I don't have any luck maybe I'll end up with a recon turbo.

Thanks for link Zingari - hadn't seen that one - some excellent detail in there.

GP
 
Over on the Range Rover Sport forum (where all the diesels have at least one variable vane turbo) this topic crops up often. A frequent cause of the problem is seized joints on the external actuating rods. I don't know if your turbo has these but worth a look?

The fix is to give the seized joint a good soaking with WD40 or similar whilst moving the rods through as wide a range of movement as possible with a suitably wire modified coat hanger.

If the problem is internal then this Innotec product and its predecessor has had good reviews.

http://www.innotecworld.com/products/sets-systems.php?productid=6

Hard to prove but I suspect use of premium fuel especially Shell VMax helps to keep things clean. Plus of course a good long run and the occasional wide open throttle acceleration (but only when thoroughly warmed up).
 
hasn't just gone into "Emission check mode" then! :floor:
 
But the car is an 04 plate so maybe before the smoke and mirror strategies from VAG - we'll probably more smoke actually, but none of the mirrors :grin:
 
coullstar said:
GP41 said:
:weed:

I know it wasn't Porsche related but I thought I'd have had some sort of response, even if it was rude. :p

If anyone's interested I've decided to add some Forte diesel turbo cleaner. Couldn't quite bring myself to squirt oven cleaner in...

Did his work?

Just waiting on it being delivered. I'm hoping to have it in time to put it in this weekend and then I'll update you. This is its first limp mode so I'm hoping I've caught it early.
 
Put a couple of bottles of Forte into about 50 litres of diesel as per instructions and took the car out. Let it warm up then gave it a blast. Over the next few runs quite a lot of nasty stuff came out of the exhaust. Hasn't gone into limp mode since. I might be imagining this but I do think it feels smoother and quieter to drive now too.

I'll probably stick another bottle in in 12 months to keep on top of things.

Time will tell whether it's been really successful but at the moment I'd say £30 well spent. :thumb:
 

New Threads

Forum statistics

Threads
124,350
Messages
1,439,414
Members
48,705
Latest member
Scratch
Back
Top