Turbo Woes

[Ed1943]

Driving my wife back home from the hospital yesterday morning and suddenly there was major loss of power (no turbo operation), foot flat to the floor to get 40/50 mph. Managed to drive the 9 miles home, rang the VW garage (10 miles from home) who managed to fit me in to check the car. Restarting to drive over to the garage and turbo operating perfectly, best for some time (previously whistling/poor operation). Garage did diagnostic check with fault code P0234 - Turbo Over Boost Stored. Carried out test plan/final control diagnosis - vacuum ok but movement of turbo wastegate partially seized, not moving smoothly and not returning to rest position. They recommend replacement of turbo at mortgage type costs (£1300).
Your thoughts please. As car is now driving as good as ever, should I continue or will turbo only get worse (another loss of power or worse).
Model is 1.9tdi with just 30,000 miles on the clock.
Many thanks
Eddie

[doctordubs]

Take it on the highway and give it some beans. The vnt system is sooting up from carbon deposit. Burn it out before it seizes completely. The mileage of your car doesn't warrant a new turbo.

Sent from my GT-S5280 using Tapatalk

[doctordubs]

Also. Have heard of guys removing downpipe from turbo and spraying oven cleaner into actual exhaust housing with good results.

Sent from my GT-S5280 using Tapatalk

[Ed1943]

Thanks for the replies doctordubs, but can you explain why the turbo stopped operating then after a short stop its operating as good as ever and how this links in with the wastegate being partially seized, not returning to closed etc. Although I'm up to speed with the vagaries of my 1933 Austin 7, the operation/problems of turbo diesels have me scratching my head (vnt system?).
Thanks again.

[doctordubs]

The vnt system uses a circular layout consisting of little flaps interconnected by a flat metal disc, connected to the actuator within the exhaust housing of turbo. Wer a normal turbo dumps excess gas to maintain turbo speed/boost, the vnt system changes the airstream/Airflow in the housing. Its the flap/disc system that jams up with carbon. Its a pain but this is a common problem with these turbos lol

Sent from my GT-S5280 using Tapatalk

[Crasher]

Also. Have heard of guys removing downpipe from turbo and spraying oven cleaner into actual exhaust housing with good results.

That causes the turbine seals to fail and fills the exhaust with oil which is an awful job to clean out. There is non long term alternative to taking the turbo off and manually cleaning the carbon off of the vane system.

http://i222.photobucket.com/albums/dd20/Crasher1964/P1010029.jpg (http://s222.photobucket.com/user/Crasher1964/media/P1010029.jpg.html)

[doctordubs]

Noted crasher, iv only heard of the oven cleaner method. Never tried it. Im a vag technician myself so id do the tear down routine anyway. Btw. Do point out wich seal in the exhaust housing will be remotely damaged by oven cleaner?

Sent from my GT-S5280 using Tapatalk

[zollaf]

Btw. Do point out wich seal in the exhaust housing will be remotely damaged by oven cleaner?

Sent from my GT-S5280 using Tapatalk
well, there are 2 seals in a turbo, one in the hot side, one on the cold side, so take your pick. if you don't think it happens, then clean one with oven cleaner and see how it goes. also, if you strip one down you will see that no oven cleaner is actually going to get to where the dirt needs cleaning from, so its a pointless exercise anyway.

[doctordubs]

Like I said. Iv only heard of the exercise. Never tried nor will I. As for the "seal" if youre referring to the titanium snap ring situated between the exhaust wheel back plate and the core your gonna need more than oven cleaner to do it any harm. Iv stripped and rebuilt many....many turbos. And oven cleaner, will not harm anything on the EXHAUST side.

Sent from my GT-S5280 using Tapatalk

[doctordubs]

Oh btw.....therz between 2-5 seals on a turbo depending on wat u have.

Sent from my GT-S5280 using Tapatalk

[Ed1943]

Thanks doctordubs/crasher/zollaf but there's no way I'm able to remove and strip down the turbo. Took car out this afternoon, plenty of high revs and 2nd/3rd gear work for about 30 mins. Will this be sufficient to clear the soot or is it likely the problem will return (loss of power) or should I drive the car more energetically for the next week or so. Or does it mean turbo removal/cleaning or possibly replacement. As I said car has only 30,000 miles but it is 6 years old.

[doctordubs]

Drive.it spiritedly once a day just pulling through 2nd 3rd and a little in fourth for 3 or so days. After that it should be ok. I believe in giving a car little pulls through 2nd - 4th every so often. Keeps the passage ways clean lol.

Sent from my GT-S5280 using Tapatalk

[Ed1943]

VW garage refers to wastegate sticking but from reading other posts this is fitted to older type turbo's. Also when problem occurred there was no warning light or message.

[doctordubs]

Every turbo has a wastegate system. 2 main is the flap type and the vnt. Wat sticks is the vnt flaps and the ring connecting them to each other and the actuator

Sent from my GT-S5280 using Tapatalk

[Ed1943]

From the mountain of information on the Mk5 Forum from Zollaf and Co., with the fault code at PO234, it looks like a visit to my local garage (who are experienced with VAG vehicles) and get their views to possible removal of the turbo and either they can strip/clean or courier to a specialist. I've now had the car for just over 12 months but prior to this it had been run on long life service plan, but I have returned to the usual 12 months service intervals always assuming that clean oil is the life of the engine. Its still running reasonably ok but I'm nervous that a major disaster could be just around the corner (or over the hill!). Its great that all this information is available as otherwise you get sucked into VW main dealers and their high prices. They had quoted approx. £1500 to replace the turbo which they specified as a Garrett type 03G 253 014 FX. Assume this is stamped on the turbo. Will let you know result with local garage

[zollaf]

http://www.turbotechnics.com/docs/catalogue.pdf

listed here, 2nd one down as soon as you get to a mk5 golf.

[Ed1943]

After having a service + can turbo clean which didn't work have bit the bullet and replaced the turbo. Performance now returned and running smoothly (bliss). Managed to get my hands on a new turbo (not refurbished) and this together with fitting by experienced local garage resulted in costs being near to 50% of main dealer cost. Many thanks for all your help.