q5dave

My buddy has a Mercedes M class with a Blutec desiel thats turbo charged. The car was leaking oil and it turns out its the turbo charger and to fix it is $5k. 84k miles on the mercedes I have a Q5 2.0T and was wondering if anybody has had a issues with the turbo were it needed replaced and what it cost. I have 30K miles, drive 35K to 45K a year.

justdanorm

did they tell him what was wrong with the turbo that it was leaking oil?

Niteshade

This just a reflection on turbo chargers from years gone by. When the first turbochargers came out one of the problems was that the oil in the earrings would coke, in other words cook until it became an abrasive sludge. This would happen say after some hard driving where the turbocharger was really heated with the exhausts gasses, and then shut down. Sort of the automotive equivalent of ridden hard and put away wet.

The oil on the hot bearings would then just sit there cooking. Some manufacturers at the time would suggest that after a period of hard driiving a good practice would be to let the engine idle for a minute to help the bearings out and prolong the life of the turbocharger. Oil leaks around the turbocharger was a possible sign of bearing problems.

I mention it here simply as helpful information, having the benefit of being an auto enthusiast during the turbo hey days of the eighties.

HotRodW

Ahh, yes . . . the turbo timer. Remember those?

From Wikipedia:

"A turbo timer is a device designed to keep an automotive engine running for a pre-specified period in order to automatically execute the cool-down period required to prevent premature turbo wear and failure. After a period of driving when a turbocharger has been working hard, it is important to let the engine run at idle speed for a period, allowing the compressor assembly to cool from the lower gas temperatures in both the exhaust and intake tracts. At the same time the lubricating oil from the engine is able to circulate properly so the turbine won't burn the lubricating oil that would otherwise be trapped within the charger with the turbine rotating at high speed. With regard to modern automotive turbochargers, the need for a turbo timer can be eliminated by simply ensuring the car does not produce any 'boost' (during driving) for several minutes prior to the ignition being shut off. Most turbo timers are based on digital electronics.

Turbo timers can usually be disabled by an external switch, this is normally done using the handbrake switch, or using an automatic one."

rdA4WtQ5

Synthetic oil and auxillary coolant pumps have made turbo timers obsolete.

q5dave

I don't believe they told him what was wrong other than it needed to be replaced

OttoNY

My '85 SAAB had a sticker on the visor advising you idle the enging for something like 30-60 seconds before shutting it off in order to cool down the turbocharger. The recommended oil change interval was 2750 miles. Even so, I remember having to replace the turbo at about 45,000 miles. We've come a long way!

justdanorm

This is true with a vehicle that does not have a electronic pump to keep oil going for the turbo. I believe the Audi's have this so that is why a turbo-timer is not needed (keeps the motor running after shutting off to allow bearing the cool down) or the need to do so manually.

JohnBoyToo

rda4 has it right...
no need for them any longer...

longer ago than I want to admit
I had a nice little 4 cyl turbo that had an automatic turbo timer from the factory.... but they are no longer needed, even on my (larger) diesel pickups and Excursions..

Jusforfun

There are only 3 Q5s on the forum at this time that are turbo charged and have over 60k miles on them so the chance of you getting a definitive answer is pretty small.
On the other hand both ROW without and US Canada Bluetec/adblue Q7 3.0 TDI and TFSI have been around longer, are showing higher miles and they are not reporting any problems.
Based on a current odo of 30k you are doing 44k a year.