Un-Sticking Your TDi VNT Turbo Vanes.....
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!
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 :drool:) 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 *****. 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).