Un-Sticking Your TDi VNT Turbo Vanes.....

[ScottyP45]

If like me, your car has suffered the inevitable sticking VNT mechanism in the turbo, here is how I fixed mine.....

DO THIS ON A COLD ENGINE ONLY!

Needed:

12mm socket and small extension

M6 hex key (allen key)

Metal tube for leverage on allen key (helps but not absolutely necessary)

Mr Muscle Oven Cleaner Foam Spray, £2.55 from Asda.

Remove the EGR pipe (2 nuts and 2 socket head screws, tight, use a metal tube slipped over an allen key and crack them off, top ones are the allens, and soak the nuts with penetrant first like wd40 or lusol or something. (I put new M8 nuts and star washers back on as the originals are rusty old tat now)

Get a length of 3mm ID vac tubing, silicon etc or anything you can find, feed the tube into the egr hole in the exhaust manifold, but using a torch, get it to turn down into the hole to the exhaust turbine and push till it goes almost right in (oer misssus ) It MUST go DOWN the hole, not in and left or right, but DOWN, this is important!!! Make sure the tubing has dropped down the cast hole that leads to the exhaust turbine, its not hard but needs care to get it in properly, once its in, it shoves right in quite easy and silicon tube cant damage anything in there.

Take a tin of Mr Muscle oven cleaner (sodium hydroxide, DONT get any on you anywhere, it burns like a BITCH. Seriously, its safe enough to do this but all risk is yours, dont get it in your eyes, or eat the foam, or rub it on yourself, or anything like that (disclaimer applies LOL) it is NASTY, extremely flammable and caustic, but it dissolves (well loosens) carbon which is what sticks the turbo up in the first place. Pull the spray nozzle off the tin, and insert the wee spout thats left, into the 3mm tube you shoved down into the turbo, THEN using a small shifter or a pair of needle nose pliers, gently grip the can's spout thru the tubing, and press down with the pliers / shifter so it injects the foam down into the turbo. Watch as it rises up the manifold hole as you dont want it anywhere near the head exhaust ports, it eats aluminium. This is not a problem tho, as the middle where the turbo port is, has a long straight section well away from the head ports so you would have to put a lot of foam in before it would reach that far, and would come out of the egr hole first.

Fill the turbo till it shows at the top of the hole the tube is down, but dont go nuts. Remember rubber gloves and bin the tubes and tin afterwards.

After an hour or 2 (mine took minutes to free but was left a couple of hours - I had the actuator off so could feel the lever sticking then suddenly it was nice and smooth) reach down and operate the VNT lever up into the actuator body and let it drop, it should shut under spring pressure and go right back to the bottom of its travel, unlike sticking at the top like it will have been doing. Then when its free, put the egr pipe on and go for a spin, change up at no less than 3k where possible once warmed up and blow that crap out of the turbo.....it will work like a charm, no more overboost or limp mode, just perfect boost and pulls like a train now

You can use a minivac hand pump to operate the actuator, and when you press the release button it should fall back to the bottom immediately, starting to move at 3" vacuum, and finished full stroke against the stop screw, by 17" vacuum (for the technical out there with such a tool - ebay £25 - very handy - can bleed stuff single handed with it too using just a bit of clear tubing).

 

[Izzy1]

good news mate.
tempted to give this a try but know jack all when it comes to engines.
do you have any pics of where you fed the tubing down the exhaust turbine?

 

[ScottyP45]

I'm sure I took pics but havent put them on photobucket, will get some up asap tho matey

Here is the bay, the crinkly pipe running vertical is the egr pipe, joins the exhaust mani on the bottom with the inlet / egr valve at the top:

Here in this diagram you can see the exhaust manifold and the egr hole on top, see how it runs down into the turbo, its the only downward hole, visible thru the outer egr hole with a torch: (our UK turbo actuator is up the other way but the manifold and cast iron side of the turbo are the same)

This pic shows the route you want the tube to take quite clearly to enter the turbo on the exhaust side,from the egr hole with the 2 studs, thru into the turbine housing. (never put anything in the intake (alloy) side, only the cast iron half). This is not the exact same as ours, its a vnt20 but close enough for illustration purposes:

 

[Izzy1]

cheers for that mate.makes sense now. did you have to replce any gaskets? and what 3mm pipe/tube did you use to feed into the turbo?

 

[tdia4]

Good write up, think I might have a go at doing this today, i've got no problems but if I clean it out it stops it happening any time soon dont it.

Do you think I could use a foamer de-greaser? Or is it best to get the mr muscle stuff?

 

[Izzy1]

mr muscle is tried and tested so might be worth using that.

 

[tdia4]

Ok cheers, does the foam disolve? Was abit worried about it going through my CAT thats all, didnt want it damageing it, only just had a new one put on.

 

[ScottyP45]

no gaskets needed, the egr pipe has a metal gasket on the bottom, reuse it, the top has no gasket. I used 3mm silicon tube i got from ebay as its close to the size of the stub on the mr muscle can when the spray button is pulled off.

It wont harm the cat, as when you do it cold (must be cold anyway), and its first started it blows the dissolved foam (now liquid) out the tailpipe immediately it fires up, and as sodium hydroxide is flammable, it burns off cleanly in the exhaust as it warms up, now on 1500 miles since cleaning it and no problems.

Has to be mr muscle as thats the only foam based sodium hydroxide (NaOH) cleaner you can get off the shelf here. There arent many things that can actually shift or dissolve burned on carbon except sodium hydroxide (its also called "Lye" (chemical name is NaOH) and is also used to turn veg oil into biodiesel.....) - NaOH is actually the base used in all non-ammonia oven and bbq cleaners, but most are liquid not foam, and that helps get it everywhere in the vnt ring and the turbine as it expands when sprayed in. The tubing is the only way to get it down into the hotwheel casing without removing the cat flange from the turbo and spraying it in (way easier this way)

The turbo is so quiet now too, no whistle except when cold if you listen very hard...3 weeks now and no codes, even pulling up the "hill of doom" a long 1:5 gradient from my in laws cottage that I could never ever get up without the car cutting into limp every ****** time half way up.....now it claws its way to the top and I'm hitting 60 by the time I crest the hill! W00t!

 

[tdia4]

Did this today, did as you said but over filled the first time and it started pouring out where i was putting it in lol, so ran to get water because i didnt want it going on things it shouldnt be on.

Put it all back together and left it 2 hours, went to start the car up.....hmmm its really loud, poped bonnet open and I had made a mistake lol.

Where the pipe goes from the egr valve to the exhaust manifold i had put the washers(for some god known reason) under the metal gasket haha, so there was now a gap, whipped it all back off and put it on properly.

Now my car never went into limp mode but since i've done this it pulls so much better so my actuator must have been sticking slightly, and now when I turn the car off I can hear the actuator rod drop back down. Impressed

 

[ScottyP45]

haha nice one mate! Success

It worked a treat for me, my actuator was sticking near the top of its travel and making 2 bar at 3k - very bad obviously, and lots of garages fit new turbos when a chemical clean costs about £3!

 

[Izzy1]

Good news Jack. Did you use a silicone tube to reach into the turbo or something else? will try and get all the stuff i need and attempt next weekend.

 

[tdia4]

Yeah I used some wiper washer pipe which worked perfectly.

 

[ScottyP45]

yeah just needs to be a neat fit onto the stepped nozzle on the top of the muscle tin, so the foam goes down the tube and not out towards your face or on your hands. The tin holds waaaaaay more than needed, and it expands a bit, so spray some, stop and check, wee bit more....until it just appears at the top of the hole that the tube is going down. Work the actuator rod up as far as it will go, and force it back down, keep doing this till it drops smoothly to the bottom by itself. I actually took the 2 x 10mm nuts off the actuator body bottom, and lifted it up and down making it easy to work the rod up and down with it...then put it back when it was free, and stuck the nuts back on, button up the egr and after an hour or 2, start it up, drive till warm then give it a blast, changing up just after 3k in each gear, i think you'll be pleased mate. The 3k gearchange is to get hot enough egt and high gas flow to burn off and blow out all the removed soot.

 

[EdgeyA4]

Hi there,

Sorry to bring up a old thread, but i tried this today, and got as far removing the 2 Nuts off the bottom of the EGR Pipe, they are completley siezed and wont budge and 1 is near rounded off, can i just put the silicone pipe down from the top of the EGR pipe as i can get the top bolts out and i could thread it all the way down into the turbo,

if not is there any other way of doing this? i.e put the silicone pipe through the inlet side of the turbo through in to the exhaust side (I.e Through the Compressor?) or any way at all?

Thanks

 

[mattpanton]

Out of curiousity, what symtoms would I be seeing if mine was sticking?

 

[EdgeyA4]

I Belive that in most Cases Presuming it is sticky vanes and not Boost leaks, Faulty N75, MAF or Boost sensor (worth checking these 1st) Symptoms are flat spots and going into Limp mode under load at around 3000RPM in 3rd 4th and 5th, and is probably not pulling aswell as it could do, but if youv always suffered from sticking vanes you might not know what it should pull like,

 

[tdia4]

I wouldnt put the pipe down the top of the egr pipe, cant see where the pipe is going and would probally end up with the pipe in the engine.

 

[EdgeyA4]

Success, Like driving an different car lol No more limp mode where it used to do it everyday wiithout fail,

Great Guide

Cheers

 

[yendall24]

or you could just treat your car to some forte diesel treatment twice a year wonderful stuff . cleans the whole fuel system on the way in . and the turbo and catalytic converter on the way out

 

[ScottD3]

The turbo is so quiet now too, no whistle except when cold if you listen very hard...3 weeks now and no codes, even pulling up the "hill of doom" a long 1:5 gradient from my in laws cottage that I could never ever get up without the car cutting into limp every ****** time half way up.....now it claws its way to the top and I'm hitting 60 by the time I crest the hill! W00t!

When I first got my car the turbo whistle was really loud (my mate behind me could hear it) and over the last several months it seem to have quieted down alot.
Am i right in thinking that my vains was stuck/sticking but have freed them selfs?

Has any one done this method with the turbo apart to see the difference?

Been reading the below link. No idea if its the same turbo as mine or ours.
VNT15-Turbo

 

[EdgeyA4]

Tbf, my turbo proly whistles louder now than before, I guess due to it spinning freer and soiling better, I woul give it ago anyway for what it costs and how easy it is, I'm a it techy and managed it lol I'm really no good with cars lol it would b worth blankinh the Egr aswell for good measure

 

[ScottD3]

Tbf, my turbo proly whistles louder now than before, I guess due to it spinning freer and soiling better, I woul give it ago anyway for what it costs and how easy it is, I'm a it techy and managed it lol I'm really no good with cars lol it would b worth blankinh the Egr aswell for good measure

I blanked mine bout 2 months ago

I might give it a go when the weather is better.

 

[jonnycraig]

Ive read quite a few threads talking about blocking off the EGR altogether, what are the benefits of doing it and why have it there in the first place if all it does is coke everything up inside?

 

[EdgeyA4]

I blanked mine bout 2 months ago

I might give it a go when the weather is better.

Ah lol there you go then, one less job haha

Ive read quite a few threads talking about blocking off the EGR altogether, what are the benefits of doing it and why have it there in the first place if all it does is coke everything up inside?

I always thought it was meant to be there to help Recycle gases to be more economical, but iv heard it also causes multiple problems, by removing it you remove the problems (Flat spots)

 

[ScottD3]

Ive read quite a few threads talking about blocking off the EGR altogether, what are the benefits of doing it and why have it there in the first place if all it does is coke everything up inside?

Generaly its better.
The valve lets exhaust gases back in to the engine to be reused. All the crap that comes out of your exhaust goes back in to the engine at lower RPM and it meant to help lower emisions. Which seems ok but all that oil, unused diesel, water, carbon and other bits and bobs is going back through your air system and covering thing is a sticky black oily mess.
The basic benefites to removing the EGR is that none of that is going back in to the engine, Better MPG, better throttle responce and peace in the knowledge that your not putting exhaust gases back in to your engine.
Do a search for people who have cleaned their EGR system, you'll all the crap thats going back in to the engine.

I did this to my land rover and this car, both cars seem to idle better, better mpg (not massive amounts but every penny counts) and better pick up at lower revs.
Never noticed any thing negative and no errors.

£5ish from ebay for 2 blanking plates, its worth a pop and if you dont like or not happy. take em off.

 

[wafers]

Cheers evilscotsman for starting this thread. I will be doing the same job to mine tomorrow having read your instructions.
Am a little concerned though..... I sprayed some WD40 on the 2 nuts today which retain the lower part of the EGR pipe, but they look absolutely screwed. To the point that I am fairly confident they will shear off tomorrow when I attempt to undo them.
Any suggestions? Otherwise I have a feeling this will turn into a very expensive and fiddly job.....
Cheers in advance for any ideas!

 

[wafers]

Also just re-read EdgeyA4's post about the same issue. Did you end up putting the tube through the top of the EGR pipe?

 

[tdia4]

Just keep at them to get them off, the nuts on my Egr pipe didnt look to good but ive had them off quite a few times and they have always been fine. Make sure you dont go putting the pipe down the egr pipe, it does need to come off.

 

[wafers]

Well, I managed to snap off the bottom stud as is was seized solid .
Done the deed, put it all back together (with just 1 stud holding lower part of the egr pipe on) and now going to fire it up and take it for a drive.
Here's hoping........
Should I get someone to drill out the lower stump and get a new nut/bolt or drive on as is?

Edit...
Just done about 15 miles in the A4. What a difference. No more limp mode, turbo pulls like a train. ****** amazing!
I can't thank the posters on this thread enough for such excellent advice and instructions!
Any thoughts on the snapped stud though anyone?

 

[keaton85]

I'm looking to clean out the vanes on a Beetle I just picked up today. I don't have the time to remove it so this looks like the best option. Will this be long turm or just a short term fix?

Currently, the vanes are not easy to move and my actuator is sticking. I pulled mbar on VCDS before and after I unstock my actuator and WOW much better. BUT the vanes are still hard to move so will hard runs to redline to keep EGTs high remove the soot or do these suckers really need a lot of work to get clean!

haha the bottom 10mm is also broken on my TDI. I'm leaving it for now since the braket is stating in place.

 

[PAULF]

Thanks for the good gen Evilscotsman.
I have a 2.5 TDi which had sticking vanes and the overboost fault.
I released the turbo outlet pipe (3 nuts) and removed the inlet hose. I fed my length of pipe in through the turbo outlet impeller vanes and gave it a good squirt of Mr Muscle. Before all the foam 'grew' out, I blanked off the outlet with a bit of card. I then turned the compressor backwards via the inlet, to try and distribute the stuff inside a bit better. A bit of moving of the actuator, repeated the squirting and moving a couple of times, and a quick test using Basic Setting, Block 11 on VCDS.
This really is a very good fix. It would be worth adding it to the 'Look here before posting, loads of Technical information for A4s and S4s', sticky, or somewhere like it

 

[ScottyP45]

Hi guys!

Hey its so nice to see this thread still getting mileage and helping folk out, yeah its a peach of a fix for under a fiver eh! People have paid hundreds of pounds for a new turbo when a can of good old mr muscle does the job for £2.50 lol

btw this applies to any VNT turbo on any tdi, vw, bmw, porsche, merc, audi, etc etc.

Anyone wishing to remove the turbo and clean it, yeah thats fine, but remember sodium hydroxide is ok on steel and cast iron as used in the hot side (exhaust) of the turbo, but reacts violently with aluminium alloy and eats it while making hydrogen gas (very flammable) so do not use it on the alloy intake side ever ever ever.

Using the old "tube into the turbo" either from the cat end or the egr hole ensures none gets into the alloy turbo intake side or near the alloy head ports.

I dont have an audi currently so only stopped by to copy this post for the guys on the baby-benz site....but i'll be back, so rock on!

 

[oiled up]

Any suggestion on how to do this on the 2.5 tdi c5 evilscotsman? Seems slightly different from your instructions so don't want to screw it up.

Thanks

 

[A4NA18]

Hi Oiled Up,

From what I understand, you have to squirt Mr. Muscle in the exhaust side of the turbo.

a. Locate the turbo
b. find the exhaust side. Usually it is the brown'ish side not the silver side. The silver side is the intake and it is made out of aluminium so do not squirt Mr. Muscle there, it will melt the turbo.
c. Undo the bolts which are attaching the turbo to the exhaust pipe.
d. get a cardboard of some sort ready
e. squirt the Mr. Muscle into the turbo. before the product starts foaming, place the cardboard in place (where the exhaust pipe was) to avoid leakage of product.
f. leave it for couple of hours.
g. go on the open road and once the engine is hot, rev it until 3000 rpm at least to change gears.

DONE.

I guess it is the above. People who tried, please correct me if I am wrong.

Speak soon! GL!

 

[PAULF]

That's pretty much what I did (see above) I would also say to move the actuator up and down, and you can feel it free off.

 

[TeKnodriver]

Thanks for the detailed info on how to do this!
got it done in the morning sun...
was simple but I did remove the airbox to shine the torch an feed the tube into the hole into turbo.

seems to pull smoother below 1.8k revs and give beter pull from 3k to 4.5k -
all while seeming smoother with faster 'pick-up' and less hesitation

let's see what a cold start is like tomorrow morning..!

Think I might repeat next week to clear the rest of the gunk - was only 1 hour work!

 

[A4NA18]

Hey TeKnodriver, What is your engine?

I have a 2.0 TDI and the EGR system is on the way and when I unbolted the egr tube to the turbo, the screws are too long and I do not have enough of a gap to let the tube into the turbo.

Has anyone done it on a 2.0tdi B7? (BLB Engine)

 

[TeKnodriver]

Hi mate,
I have AFN '98

fitting the foam-feed-tube is a bit trickier than the above daigram shows but after a few minutes it should work

I have a a pair of EGR blanking-plates on order, maybe you could try this?
P)

 

[BudgieV8]

I have a 1998 A4 1.9TDi AFN 110. Good info on this post! I will try this as well - as I too have to 'switch-off, switch-on' to reset the limp mode. I'm also looking at blanking plates. As Im new to Audi TDi stuff, where do you fit them? From the original pics at start of post, One on the EGR hole on the exhaust manifold, & where do you fit the other? Remove EGR, EGR pipe etc & blank the inlet manifold? - Do I then block the pipe off the back of the EGR as well? Thanks, Paul

 

[Turbo unit]

Tbf, my turbo proly whistles louder now than before, I guess due to it spinning freer and soiling better

The reason its making a whistling noise now is beacause the carbon hit the turbine wheel slightly bent the blades and took it slightly out of balance(turbo is on its last legs and wont be long now 2k miles at the most i recon depends on how you drive it) good old mr muslce loves the jobs you hate better give him a call to fix that lol