Revving it ridiculously hard from cold.

How would that affect the turbo? The rev limiter kicks before the turbo really spools up and the turbo likes to be cold. Colder oil is better for the bearing and reving the engine will increase the oil pressure which is also better for the bearing. The exhaust gas volume is also much lower than when the car is under load.

I guess a turbo likes cold input air, sure.

 

How is colder oil better for the bearing? Something moving that fast needs the lubricant to respond asap, surely?

...How is colder oil better for the bearing...

It's slightly thicker.

But moves slower. Six of one...

As above,the emissions test is usually done about 3/4's of the way through test before they do the brakes,they leave them idling to warm up properly for most of test before they get to emissions part.

Illuminating discussion. Feel like I know more now. Thanks everyone.

 

I'll go to church tomorrow.

 

Then I'll buy a lottery ticket.

But moves slower. Six of one...

Faster - the pressure is higher than idle.

We are of course assuming the turbo has actually failed. A common mode of failure would result in clouds of smoke. It wouldn't take much investigation. I would take it somewhere else ASAP and get the codes read. If the ECU has gone into limp mode, the turbo won't boost but it doesn't necessarily mean the turbo has failed.

If the turbo has failed it's bad luck - hope it hasn't.

Ha. I still say slower, but I'm a chemist: pressure on fluids doesn't change much (hence hydraulics).

 

Thanks tho. I'm going to take it to the VAG place down the road on Monday. Would be nice if it was just a hose...

Viscosity index.

Yup. Changing pressure has little effect on the viscosity of a fluid.

The oil pressure varies from about 1.25bar at idle to about 2.5bar at 2000rpm and gets close to 5.75bar at the redline.

But its ability to penetrate a joint/interface is down to its viscosity much more than the pressure it's under, right?

 

(This has all gone wildly off topic, hasn't it?)

I wouldn't let them even change a bulb on mine.

I've had two major incidents in the dim and distant past -

one involved loose bolts (I guess that is why nowadays everyone disclaimers this!),

secondly was mistaking the plugs/model needed on a service which led to major engine damage.

Never used them since for that kind of work (or MOT)

 

(Perhaps they should have taken a leaf from any good mechanic or Haynes service manual and compared the removed part to the one they were fitting!)

Under duress (took embarassing them in the store to take notice) they attempted a repair free due to them damaging

but I suspect it was more of a bodge as the otherwise sweetly running motor ended up far from it after not many miles which is why I decided to just chop it into a garage when I bought new many miles ago.

 

That said there are some fair bargains to be had from them what with that £5 Bosch front wipers recently so can't bash em that bad eh ! Just no servicing !

Bad luck, if they had managed to get through the MOT it would have blown up when you were on your way home.

 

It's not their fault and it's not yours, these things do just happen. Mechanics don't abuse cars as a rule, they simply don't have time and MOT testers certainly don't abuse cars, they just leave them running so they're nice and hot then perform the tests.

If the turbo has not blown maybe its just the boost pipe blown off the IC or turbo, very common on the Fabia for some reason. Gives the same symptoms as turbo failure (smoke, noise, big bang).

when revving and not under load the turbo will not be under and load and hardly creates any boost. making it hard for ne me to believe it went fron just moving aroubd yard or testing.

its more likely to be thrashed down the road to see what it goes like or to do a butty run. as a mechanics gotta eat

If the turbo has not blown maybe its just the boost pipe blown off the IC or turbo, very common on the Fabia for some reason. Gives the same symptoms as turbo failure (smoke, noise, big bang).

a car will still run with boost pipes gone and also fabias dont create clouds of black smoke with intercooler pipe off.(mine dosnt)

Mine plooms black smoke with the intercooler pipe off.

I cannot believe people actually think this is likely to be an mot tester's fault.

Even most backstreet garages, let alone huge ones know that customer cars aren't to be used for runs to the shops ect. Also that cars should be allowed to warm up (however not required to) before being tested. It'll be one of those things that's just happened, bad luck that it wasn't in your possession at the time.

Plooms of white smoke is the usual signs of a turbo failure.

Unlike the petrol emissions test, during the diesel smoke test, a diesel engine is revved to maximum RPM and held against the governor for a short time. They should make sure the engine is at operating temperature before the smoke test. There are disclaimers around every MOT centre I've been to that advises the test centre is not liable for damage to the engine sustained during the test because if the car has low oil level, not had a recent cambelt change there is a big risk that something is going to break during the test.

 

It is quiet possible for a turbo to blow as it may have been on its way out before the test. Chances are it would have blown soon anyway even without the test.

 +1 most places do have the 'smoke test' poster up detailing what is involved. Think you'll be very lucky to get any money out of them unfortunately, just sounds like bad timing and coincidence.

 

Out of interest was it showing any signs of failing? Usually towards the end of their life they often sound like a police siren at low revs, more pronounced from a cold start usually.

a car will still run with boost pipes gone and also fabias dont create clouds of black smoke with intercooler pipe off.(mine dosnt)

 

Mine and my mates both do. 

 

As others said, unlucky but if it hadnt gone then it'll have gone a day or so later so dont blame the garage, not their fault. 

Right. Local VAG garage says £1200 for a Garrett with 1 year warranty, or £1400 for a VW part with 2 years. Halfords reckon they can do it for around £500.

 

Big difference!

Jesus christ that's a lot of money! Talk to Xman on here and buy one of the PD170 hybrids he has. They are plug and play, and would just need a new map for it.

Right. Local VAG garage says £1200 for a Garrett with 1 year warranty, or £1400 for a VW part with 2 years. Halfords reckon they can do it for around £500.

 

Big difference!

 

Get Halfords to do it, that's cheap, they're doing you a favour.

Seems that way. Still has 2 year warranty.