My 53 plate Octavia diesel had lost power and I got no turbo boost so I ran some Wynns Turbo Cleaner through it. It seemed slightly better but not really right so a week later I did the same again. This time when taking it for a run after treatment it suddenly revved up to screaming point and I switched off the engine to stop it as taking my foot off made no difference. Started again ok but still no boost so back to the workshop where I noticed the vacuum pipe to the waste gate was holed where it was clipped on. Changed the pipe and went out again and the car had plenty of power - brilliant! BUT there is a howling noise on acceleration and it smokes like hell. Seems to be burning oil. What could I have done to cause this?

Sounds like it was burning oil.  Now that might be oil from bearings in the turbo (failed oil seals) or some oil in the intercooler pipework (seems unlikely, though)

 

The anti-shudder valve in the EGR assembly probably saved your engine when your turned it off.

Cranked her up again today and the smoke was pretty bad so I dare not take it on the road. Plod would stop me for sure. I was reading on here about blanking off the EGR and that made sense but now I'm wondering if it is going to mean a new turbo. What would a recon or used one cost anyone?

hmm if you had a runaway there may be engine damage...

carparts4less sell recons I think.... avoid anything cheap and chinese looking on ebay!

Friend of my brother in law (yeah, I know!) says get another turbo. The engine does not knock or rattle and the car drives OK apart from the excessive smoke. He reckons the oil is getting in from a failed seal in the turbo. I don't see any reference to it in the Haynes manual so the question is can it be replaced. The annoying thing is the car was running lovely before I started to clean the turbo, apart from not climbing hills!

Changing the seals is not a DIY at home job.  You can either take a gamble and buy a second hand turbo if you can find one of a low mileage (not sure what yours has done), or buy new/oem one.

 

Fitting the turbo isn't that hard.  You might need a replacement oil feed pipe and a set of gaskets (inlet and exhaust manifolds, exhaust, oil return)

Thanks for your advice gents. I'm still not sure where to start. I don't think there Is engine damage because it starts and runs without noise, although it certainly churns out a lot of blue smoke. Before I started to "mend" it the car ran smoothly and economically and I did plenty of miles like that. The engine can't be too bad as it passed the MOT emissions test a few weeks ago. The only problem was loss of power climbing sleep hills, hence the turbo cleaner. Is it possible that the cleaner has damaged the turbo oil seals? I took the pipe off the EGR and it is pretty oily in there too. Why would that be? Trying to avoid buying a new turbo due to cost but concede there will be cash spent somewhere - just need to be sure I spend it right if possible.

How does the turbo cleaner product work? Do you pour it in with the fuel?

The cleaner was the wynns one that you spray into the pipe from the air filter box. I blame this for the runaway as I think it had left a residue in the pipe which got gulped in in one lot!

Just to update I fitted a new turbo core which works OK but must be set up wrong. The old one had a broken shaft. Now there is a loud howling noise from the turbo region until it kicks in at around 2000 rpm and it smokes like mad when starting after standing overnight but not once up and running.

It could be that as the pipe to turbo was holed you were not getting boost and therefore turbo not working or being stressed. This may explain why your car was appearing to run ok. Now you have connected pipe and have boost your turbo is under stress and will blow smoke if seals gone. Does it smoke bad on start up. If not suggest turbo and engine is fine. Just my 2p worth

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It could be that as the pipe to turbo was holed you were not getting boost and therefore turbo not working or being stressed. This may explain why your car was appearing to run ok. Now you have connected pipe and have boost your turbo is under stress and will blow smoke if seals gone. Does it smoke bad on start up. If not suggest turbo and engine is fine. Just my 2p worth

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Sorry meant to say turbo gone and engine fine.

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I'd have the engine thoroughly checked and if you've been lucky by avoiding oil starvation the turbo professionally replaced - spooling up like it has done could have disturbed the vanes as well as damaged the seals. Blanking the EGR is well worth while, as is a de-coke, but ONLY when your system including the intercooler has been checked over professionally. An EGR blank also triggers the emissions warning light and therefore enters you into a mapping scenario. The cleaner won't have caused the runaway - a change in boost brought about by the reconnected pipe will be the culprit. I wouldn't entertain a rebuilt turbo - they're an essential item and OEM or new hybrid would be the way forward. Regards