This is a classic issue with the k03/k03s turbochargers; it seems, after a certain amount of heat cycles, they crack or sometimes, the auxiliary waterpump, that cools the turbo, might fail and contribute to this issue.
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I did a head job on a 2001 Audi TT with the AWP 1.8T and when I removed the head/exhaust manifold, it was cracked in the EXACT same place, on the hot side of the turbo.
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On another K03 Turbocharger; from a 1997 Audi A4 1.8T, the crack was in the same place also.
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The Audi K03, had low boost issues; once the turbo came off, it was apparent, that the wastage was loose/worn and there was a crack on the sealing area, causing a boost issue.
So, I have seen this on two 1.8Ts; that I have worked on and on the web, it seems to be a known issue. In the case of the Audi A4, the crack, looks like it went through the whole casting and cracked at the wastage as well. I can only assume on the Audi TT; it was going to keep traveling and @ over 100k, 20 year old car, the turbo was going to go eventually and so, we recommended to the customer, to get a new one. We researched the rebuild route and the rebuilders; mentioned the cracking issue but didn't have extra castings and researching the web, there seems to be cheap Chinese replacements.
The customer, was going to keep the car long term and love it, a Audi TT convertible, felt he was willing to spend the dough. We found a genuine Borg Warner oem turbocharger from FCPEURO and they offer a lifetime warranty, on any parts they sell, so that seemed to be the best solution, highest quality part, warranty for life.
Because, of the crack prone nature of the k03s and the fact, we had seen the crack travel to the waste gate, we felt, that was the wisest solution for a stock turbocharger. As you know, it takes quite a bit of time and effort; to get the head off and that is the best time, to access the turbocharger. After a rebuilt head, timing belt kit, new turbocharger and gaskets, typical replacement tune up parts, coolant, oil, filters, etc, etc, the bill was $4k+, when it was all said and done. Thankfully, everything went according to plan; the engine started right up after reassembly; the lifers quieted down after warm up and the new turbocharger, really helped the boost and the car ran perfectly! A happy customer and it is his baby, so he was happy to have to fixed.
I'm not a welder, however; that nature of the castings and how we have seen, the cracks travel through the casting to the waste gate sealing area, replacement would make sense.
The customer wanted a stock turbo but if this is your case, it could be a opportunity to upgrade to a ko4 or a "hybrid" modified k03/k04 setup or go bigger, where only your imagination and pocketbook limits your choices.
I did a head job on a 2001 Audi TT with the AWP 1.8T and when I removed the head/exhaust manifold, it was cracked in the EXACT same place, on the hot side of the turbo.
On another K03 Turbocharger; from a 1997 Audi A4 1.8T, the crack was in the same place also.
The Audi K03, had low boost issues; once the turbo came off, it was apparent, that the wastage was loose/worn and there was a crack on the sealing area, causing a boost issue.
So, I have seen this on two 1.8Ts; that I have worked on and on the web, it seems to be a known issue. In the case of the Audi A4, the crack, looks like it went through the whole casting and cracked at the wastage as well. I can only assume on the Audi TT; it was going to keep traveling and @ over 100k, 20 year old car, the turbo was going to go eventually and so, we recommended to the customer, to get a new one. We researched the rebuild route and the rebuilders; mentioned the cracking issue but didn't have extra castings and researching the web, there seems to be cheap Chinese replacements.
The customer, was going to keep the car long term and love it, a Audi TT convertible, felt he was willing to spend the dough. We found a genuine Borg Warner oem turbocharger from FCPEURO and they offer a lifetime warranty, on any parts they sell, so that seemed to be the best solution, highest quality part, warranty for life.
Because, of the crack prone nature of the k03s and the fact, we had seen the crack travel to the waste gate, we felt, that was the wisest solution for a stock turbocharger. As you know, it takes quite a bit of time and effort; to get the head off and that is the best time, to access the turbocharger. After a rebuilt head, timing belt kit, new turbocharger and gaskets, typical replacement tune up parts, coolant, oil, filters, etc, etc, the bill was $4k+, when it was all said and done. Thankfully, everything went according to plan; the engine started right up after reassembly; the lifers quieted down after warm up and the new turbocharger, really helped the boost and the car ran perfectly! A happy customer and it is his baby, so he was happy to have to fixed.
I'm not a welder, however; that nature of the castings and how we have seen, the cracks travel through the casting to the waste gate sealing area, replacement would make sense.
The customer wanted a stock turbo but if this is your case, it could be a opportunity to upgrade to a ko4 or a "hybrid" modified k03/k04 setup or go bigger, where only your imagination and pocketbook limits your choices.
