Uh oh, has my turbo blown up?

[aerodynamica]

Going along the M-way, overtaking, just off boost and then a big 'puff' sound and the accelerator dropped and then no power and the aftermarket boost gauge fitted by a previous owner, was showing zero boost. I could hear a rushing sound as it drove and I thought the pipe to the boost gauge had popped off and that was all, stopped in service area and found the turbo pipe to the intercooled had come apart at the join above the turbo. Refitted it and retightened the clip and set off - all was good for a few miles until 'puff!' same again, this time I was taking it easy.

So there was quite a bit of oil splatted out from when the pipe seperated, when it was running there was a slight sound of a blowing exhaust from the pipe that made me think the seal within the turbo might have blown and the exhaust gas was getting through, Think the turbo dump valve is working because you can hear it when driving. so don't know, could there be a blocked intercooler?

I didn't bother reattaching it since it keeps blowing off.

Any ideas?

[BenC5HDi]

Stuck wastegate? What car is it? If the wastegate is sticking shut and it's developing uncontrolled boost, it could blow the pipe off. This makes sense if it runs ok when the pipe is reattached.

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[aerodynamica]

It's xantia 1.9td, how can I check for stuck waste gate? You can certainly hear the turbo spooling up and stop with the throttle being held and that made me think the waste gate was functional. Can it suddenly stick? The car is driven regularly. Thanks for the help

[aerodynamica]

Maybe the rubber hose for the waste gate has split

[RichardW]

The oil is normal. They need to be tight if they are not to pop off - happened to me a couple of times; once just after I had replaced the timing belt, which was a heart sinking moment! What boost was it making on the gauge before it popped off? Waste gate on these is integral to the turbo, there's no hoses.

[aerodynamica]

Hi Richard, it was showing a tiny smidge under 1 bar the first time, overtaking so probably full boost. Second time half as much about 0.5 bar. Not sure why I thought there was a pipe outside the waste gate just had a recollection of seeing it, might be thinking of the oil return.
If it is sticking is there anything I can do or does the full unit need to come off for recon?

[aerodynamica]

Yes, still holding after tightening the clamp again. Drove around for a while earlier and seems ok, didn't do any sustained throttle action though and checked the boost didn't go above 0.5b (one way to keep down fuel consumption!)

[Old-Guy]

Oil in the inlet pipery is normal as the crankcase breather is just down-stream from the air-filter. The max. boost is 0.7b according to an under-bonnet sticker on the 'Green Lady'. 0.7 bar is about 10 psi, the pipe on the inter-cooler is about 2" dia (3sq in) so there's a whopping 30lbs+ of force pushing the pipe off!

[aerodynamica]

Thanks, nice bit of deduction on the force pushing the joint apart it could simply have been the heat and constant pressure at the time aggravated by maybe a rubbish clip. About half an hour earlier I'd been in nose -to -tail football traffic for quite a while so a lot of heat soak into everything is possible. I think at least I'll get a new jubilee clip of the best quality and try and secure it as best as possible