V50 Engine Turbo : V50 1.6Hdi (D4164T) 2010 - VNT turbo control issue ?

[pinballdave]

Originally Posted by Sidji

Thanks for the advise CLAN, but I never had any fault code related to software whatsoever. Moreover, the car has been running nicely for few years before starting gradually to loose power / torque. And despite 45+ years working in automation and control systems, I've never seen a software (nor hardware) failing gradually... but sure, I may have missed something

Software bugs can exist for a very long time before something happens that causes them to be discovered.

There could be a bug in the ECU software that doesn't affect the running of the engine at all, but causes problems with the diagnostics. This could make a simple fault very difficult to diagnose, and a software update that fixes the diagnostics output, could make it much easier to figure out.


Having said that, I bought my S40 (also a 1.6 DRIVe) with a failed turbo. I disassembled the exhaust housing of the old turbo and there was a fair bit of carbon build up around the exhaust vanes that did restrict their range of movement. The car had a few faults, so I don't know if the carbon build up was caused by one of these other engine problems, but it could be worth checking if you're suffering from boost issues.

[iainmd]

Originally Posted by Clan

it will cost you much more by guessing you need it professionally diagnosed so it is repaired properly, Have you got the latest software for the engine ? That is very Important.

It amazes me you are happy to spend £1000 on a guess ( turbo) but wont get it diagnosed properly then repair it yourself.

New turbo cost £430. I'm perfectly happy to spend that now because every other component of the turbo actuation and vacuum system has been checked or replaced and all diagnosis, done by a friend who is a retired Volvo specialist, points to the VNT mechanism having failed.

I am perfectly happy to repair it myself on a car that's worth less than £1000. Especially when my nearest two Volvo dealers are less than trustworthy. The car hasn't been to a Volvo dealer in nearly 8 years but considering I've got 170,000 miles out of this turbo I'd be rather amazed if software was key to it all. I'm more suspecting that the damage was done by carbon build up when I had a failed injector seal.

[Clan]

Originally Posted by Sidji

Thanks for the advise CLAN, but I never had any fault code related to software whatsoever. Moreover, the car has been running nicely for few years before starting gradually to loose power / torque. And despite 45+ years working in automation and control systems, I've never seen a software (nor hardware) failing gradually... but sure, I may have missed something

A turbocharger is very simple and should last forever if the oil is correct and changed as per service schedule. well keep us informed as to how it went 👍

[Sidji]

Originally Posted by Clan

A turbocharger is very simple and should last forever if the oil is correct and changed as per service schedule. well keep us informed as to how it went 👍

Well, I agree that a turbocharger is fundamentally a simple construction that may last, as long as the bearings lubrication is OK and that temperatures constrains do not exceed tolerances by design. Notwithstanding the fact that fitted on a diesel engine coupled with a stupid EGR system that - by design - fills the entire engine (including the TC) with carbon particles...
Let's just wait and see Iainmd's findings, I'm confident (although afraid of) he may well be on the right track...

[iainmd]

New turbo arrived this week but I'm away this weekend so it'll be next week before I get round to fitting it.

[iainmd]

Right, I've good news to report. Turbo replaced and I'm back to full power and all is well. When I took the old turbo off and placed it on the ground (exhaust side down) a shattered blade fell out of the exhaust port. Clearly the exhaust side blade mechanism has disintegrated.

Got to admin it was a pig of a job and took me about 4hrs but well worth the end result. Another V50 saved from the scrappy and a very happy owner :-)

Turbo was about £450 from Autodoc and no requirement to send the old one back. Was a brand new Garrett 753420-5006S.

[Sidji]

Hey Iainmd, so not only was your diagnostic fully correct, but you also have managed to remedy on your own, congratulations !
I still hesitate to attempt managing the same operation: I'm not a real mechanic and where it took 4 hours to you, it would probably take 2 days or more to me. Did you also replace the oil lines with banjos and gaskets ?
Anyway, thank you so much for sharing this as well as for the pictures

[iainmd]

I decided to keep the oil lines. They appeared in good condition and the turbo hadn't been starved of oil. The replacement turbo came with new washers and gaskets (including those for the banjo bolt) so they were replaced but I kept the original banjo bolt.

Getting the oil drain pipe back on was genuinely the hardest part of the job. The two allen bolts are in about the most inaccessible place you could imagine and the oil pipe isn't very long.