Turbo Bods! i need some of your general knowledge please

DaveA3

Audi A-Trizzle!
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Hi Mechanical Genius',

A mate of mine has an on going court case about his engine screwing up a few months after he bought the car. As investigation is on going but its believed to be turbo failure. Ive pasted a snippet below from someone on the Renault forum who stated pretty much that because he used an engine flush it pretty much accelerated the turbo failure.

Does flushing your engine really cause an already damaged turbo to damage faster? or even cause damage to a healthy turbo? or is he just chatting nonsense.

He has a Renault Scenic 1.5 DCI 80bhp with the KKK KP35 turbo

Here is the snippet:

"The report is what I thought it would be as the garage are really not in a position to say whether the fault existed before or not. You also need to remember that you are not defending this but you need to be in a position to counter what might be his defence.
However there is some good news in this.

Firstly you state in your last PM that the "injection light was on". Now my thinking is that, as you state you put it down to the fact that "all diesels smoke". The injection light was probably on because of the oil leaking from the turbo seal contaminating the catalytic convertor.

Next, the report states that there is damage to the no.1 piston. This damage will not usually occur from a turbo failure. That is of course that the engine didn't start pumping oil in in sufficient quantities as to run it dry. We know this didn't happen. So this indicates that not only was there a fault with the turbo but also one with the piston as well so overall we now have evidence of potential multiple failures.

The next thing is the head being sent off. Why they have done this I don't know as they were under instructions just to attempt to find the root cause. A totally unnecessary thing to do at the moment if at all.

Sludge will always be on the inlet side of the turbo in one way or another. However the engine cover evidence is interesting. It depends usually on the degree of contamination. The injectors are difficult to seal and will give off an invisible mist but if you are saying it's soaked in oil then the likelyhood is it is actually engine oil emitting from the induction side of the engine under pressure from the turbo. This indicates the seal within the Turbo had been leaking for some time.

Whilst you actions might have accelerated the failure I think the report gives sufficient evidence to support a statement that on the balance of probability that the turbo was indeed in a poor way at the time of purchase. I would though as previously said keep very quiet about the flushing oil.

There is a reason why you might not see the same with VW's and your Renault in that I'm pretty sure the turbos use a different bearing set up as well as diesle injection setup let alone the way the turbo is cooled. So you can't really compare the two.

Sorry it's a bit brief but overall there seems enough for you to argue the case provided the dealer doesn't get someone like me to look at it and argue on his behalf. If this happens then you would be entitled to respond but if it comes to that then let us all know."

CHEERS! ;)
 
All I can say is that turbo's require oil not only for lubrication but also they use the oil to take up the play in the bearings.

As the turbo is a rotational mass any damage already caused to the turbo will only get worse over time. As more play develops in the bearing the compressor blades will move more, possibly catching the housing causing the blades to wear. This also put load on the thrust bearing and casues that to wear as well.

I don't think engine flush by it's self could cause the turbo to fail, however, if the turbo was wearing out anyway the use of engine flush could possibly speed up the process, one which would/could have occured anyway.

I would have a guess that as flush isn't as thick as oil the amount of support the flush was able to supply to the bearing possibly wasn't enough on an already worn bearing and thus caused a premature failure. This is all conjecture obviously but I doubt on it's own the engine flush casued the turbo to fail, it just sped up an already likely outcome.

The only other possibility is that the engine flush did it's job too well and removed a load of junk that then got stuck in the turbo oil feed, blocking it and starving the turbo of oil.. Then I would have to say that's just bad luck!

gut feeling is the turbo was toast anyway as it was leaking, oil flush was either coincidence or it just accelerated the failure. If the seal was leaking then the likely hood is the turbo was damaged already and only going to get worse.
 
thanks dude so there may be some truth in his statement. Who knows then i guess. be interesting now to see what the judge has to say.