Smoking ABY Avant
I've got a customers '93 Avant, he thought the turbo was whistling badly, so he decided to bring it down for a replacement.
Initial diagnosis, when the engine was revved, on the overrun (in neutral) there was a 'whistle', akin to an intake leak. The car has done 130,000 miles. I removed the turbo, and I've never seen anything like it. The turbine wheels were seized solid. So, while I doubnt the whistle on overrun wasn't related to the turbocharger, it was certainly dead. The induction pipe and the boot which connects it to the throttle body were absolutely dripping oil. My customer said it did smoke a little on occasion (a little?)
I took it to my local turbo recon. company, whom I have used for many years, and have always found very helpful. They too tried to turn the comp. wheel by using a socket on the retaining nut, and shock, horror, the nut actually detatched from the shaft! I'm not sure how tight it was, but if it was easier to loosen it rather than turn the shaft, it must have been pretty hard for the exhaust gasses to move it.
2 days later (yesterday morning), I collected a recon. unit, a spec I have used in the past with no problems. It's a K26 - 6411, with a slightly larger comp. wheel than the stock K24, and definitely a larger hot side. Fitted the unit, and fired the car up.
1 minute on idle produced plumes of blue smoke, which I presumed was the residue in the induction system and probably the intercooler. I took it for a test run. It pulls very strongly, not as low down as the stock K24, but not as high up the rev range as an RS2 either. It pulled strongly and revved cleanly to 7,000 RPM without any flat spots.
On returning, the smoke had dissappeared, running really clean. Left it stood for 10 minutes, restarted and lo and behold, that offending blue cloud was back again. It takes about half a mile of driving to clear, and it appears to be ok, even after mixed driving, which lasted fo 2 hours. When cold, the 'whistle' on overrun is evident, last about 5 minutes into the warm up phase, when blipping the throttle doesn't produce the noise.
I have now fitted the same turbo to another ABY, and guess what? No smoke!
While it was off the Avant, I checked the oil return pipe for any obstruction, and made sure the oil was at the right level. I have since carried out an oil change, but refitting the turbo 
still produces oily smoke. I'm not sure if it requires a long, hard run, possibly oil still in the cats? (they'll be knackered then) or in the intercooler?
The owner says he keeps losing water, he can see drips where it's been parked, possible headgasket? I'd appreciate some feedback on this,
before I literally put my fist through the screen. 
Initial diagnosis, when the engine was revved, on the overrun (in neutral) there was a 'whistle', akin to an intake leak. The car has done 130,000 miles. I removed the turbo, and I've never seen anything like it. The turbine wheels were seized solid. So, while I doubnt the whistle on overrun wasn't related to the turbocharger, it was certainly dead. The induction pipe and the boot which connects it to the throttle body were absolutely dripping oil. My customer said it did smoke a little on occasion (a little?)
I took it to my local turbo recon. company, whom I have used for many years, and have always found very helpful. They too tried to turn the comp. wheel by using a socket on the retaining nut, and shock, horror, the nut actually detatched from the shaft! I'm not sure how tight it was, but if it was easier to loosen it rather than turn the shaft, it must have been pretty hard for the exhaust gasses to move it.
2 days later (yesterday morning), I collected a recon. unit, a spec I have used in the past with no problems. It's a K26 - 6411, with a slightly larger comp. wheel than the stock K24, and definitely a larger hot side. Fitted the unit, and fired the car up.
1 minute on idle produced plumes of blue smoke, which I presumed was the residue in the induction system and probably the intercooler. I took it for a test run. It pulls very strongly, not as low down as the stock K24, but not as high up the rev range as an RS2 either. It pulled strongly and revved cleanly to 7,000 RPM without any flat spots.
On returning, the smoke had dissappeared, running really clean. Left it stood for 10 minutes, restarted and lo and behold, that offending blue cloud was back again. It takes about half a mile of driving to clear, and it appears to be ok, even after mixed driving, which lasted fo 2 hours. When cold, the 'whistle' on overrun is evident, last about 5 minutes into the warm up phase, when blipping the throttle doesn't produce the noise.
I have now fitted the same turbo to another ABY, and guess what? No smoke!
While it was off the Avant, I checked the oil return pipe for any obstruction, and made sure the oil was at the right level. I have since carried out an oil change, but refitting the turbo still produces oily smoke. I'm not sure if it requires a long, hard run, possibly oil still in the cats? (they'll be knackered then) or in the intercooler? The owner says he keeps losing water, he can see drips where it's been parked, possible headgasket? I'd appreciate some feedback on this,
before I literally put my fist through the screen.
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