And another, from a turbo repair specialist

http://www.turborepair.com/index.php?optio...Itemid=154

Quote:

When your engine is first started, there is a very slight delay until the oil being pumped from the engine's oil pan reaches the turbocharger. In that amount of time, the turbocharger is already spinning many times faster than the engine. We know that the oil is the only lubricant for the turbo, so it is very important that it is being delivered quickly and efficiently to keep from damaging the bearings in the turbocharger. In this critical time, it is best to allow the car to idle for at least 3-5 minutes before driving off for the first time that day.

Quote:

We know that a turbocharger operates at a very high rotational speed and it is fed lubricating oil from the engine, so it only makes sense you want to slow down the turbo's speed and also provide it with oil before shutting the car down. Once you turn off the engine in your car, the turbocharger will continue to spin for up to a minute or more and during this time oil is not being delivered to the turbochargers bearings, causing wear. To help prevent this from happening, we have been told in the past to let the engine idle for a few minutes prior to turning off the key. The good thing that happens during this time is in fact the turbo will slow down, but if allowed to idle for to long the temperature of the engine compartment, engine oil and the turbocharger will start to increase. The reason for this is today's car is designed to be moving while it is operated, allowing air to pass through the radiator and engine compartment, keeping it cool. The best thing is to drive your car as easy as possible when you are getting close to your destination. Once you are safely in your parking spot, allow the car to idle for no more than 2 minutes. This time will be adequate for both the turbochargers speed to slow, and for the temperature not to increase in the engine compartment.

And while we are on the subject of turbo failures

Quote:

Turbochargers already operate at a high revolution speed, and any air leak after the compressor will cause the turbocharger to work even harder to overcome the pressure loss. Remember that the wastegate actuator on most turbochargers regulates the amount of exhaust energy present at the turbine wheel required to produce the shaft speed necessary to turn the compressor wheel fast enough to create boost pressure. The turbochargers wastegate is blind to the fact there could be a pressure leak, so it is going to try and force the turbo to over come this leak until the desired positive manifold pressure is obtained. This of course will create a turbocharger over speed condition, cutting the life of the turbocharger drastically.

Thanks for this info - very interesting. I recall reading (about the TD6 engine I think) something about avoiding prolonged idle after cold start up as there is a potential for inadequate oil circulation at such pressure. Not sure how true this is.

Essentially easy turbo housekeeping is to treat it with care at start and stop and you are helping yourself in the process too. I always unbuckle, turn off all elec equipment and then turn off engine but even that seems a bit too quick.

Thanks again. 405 AB exec seats Baltic and Cirrus
93 RR Classic efi

Remember it's easier to get forgiveness than permission!

Gone in order:
4.4 TDV8 SE - gone to a good home
93 Classic hard dash Plymouth Blue
03 L322 Oslo Blue
2000 Disco TD5 ES Epsom Green
98 P38 Rioja Red
89 Classic Cairngorm Brown

what are you going to say to a parking warden that 'asks you to turn off your engine, or face a fine' this was in the news recently.
also, all modern cars switch off at the traffic lights etc. this can be overridden, but I reckon it will be outlawed.

at least it's a great tool for the dealer, saying, 'the previous owner, nice chap, he meticulously cooled down before switching off etc. ' -yeah-right!

Bo ks to any TW who thinks they know my car better than me.  405 AB exec seats Baltic and Cirrus
93 RR Classic efi

Remember it's easier to get forgiveness than permission!

Gone in order:
4.4 TDV8 SE - gone to a good home
93 Classic hard dash Plymouth Blue
03 L322 Oslo Blue
2000 Disco TD5 ES Epsom Green
98 P38 Rioja Red
89 Classic Cairngorm Brown

Well, read rule 123 of the Highway Code, and get 20 pounds out! It's enforcement to control pollution.

It takes a lot of £20's to cover paying for a new turbo, or 2

Wouldn't the fact that you've parked mean you've been pootling about at low boost / exhaust temps so the turbo will already be cool-ish?

I always chuckle when I hear someone blip the throttle just before turning the ignition off

Back to the OP's original post - my 3.6 has just had a new turbo Absolutely nothing to do with carbonised oil bearing failure - the position monitoring part of the actuator was FUBARd. The mechanical bits were fine

FWIW I has a 3.6 for a couple of years and didn't have any problems with the turbo, another member has it now and AFAIK he hasn't had any problems either, I didn't treat the car in any way special. I have had turbo diesels for years and never had any problems and neither do I know personally anyone who has. I don't think I was lucky but rather those that have had turbo problems have been unlucky, problems that I did have, alternator, front and rear bushes etc I pretty much expected around the 75k mark. Geoff

Cummins!!! That modern TDi manufacturer

Remind me, are they in the same class as Listers?

Come on chaps, we are talking year 2000> technology here! Not that of the 1950’s or that of static genset TD engines! OK so JLR took a perfectly good “proven” Garret turbo, removed the actuator assembly and replaced it with there own

Granted if you want your turbo to last longer! Change the oil regularly and drive sympathetically when starting from cold but, certainly don’t need to be treating it like a Mitsubishi Evo with 2000bhp and a turbo the size of wiltshire!

And MOST important! If you have an EGR issue... DONT IGNORE IT!!!

Is Garrett modern enough for you Craig?

http://www.turbobygarrett.com/turbobygarrett/faq

Quote:

A turbo timer enables the engine to run at idle for a specified time after the ignition has been turned off. The purpose is to allow the turbo to cool down thus avoiding "coking" ("coking" is burned oil that deposits on surfaces and can lead to blocked passages). The need for a turbo timer depends on how hard the turbo and engine is used. Running at full speed and full load then immediately shutting down (heat soak) can be extremely hard on a turbo. Water-cooling of the turbocharger's center housing has essentially eliminated the need for turbo timers or extended idling periods.

Or HKS?

http://www.hks-power.co.jp/en/support/faq/turbo.html

Quote:

Sometimes while driving or right after you stop a car, the turbo charger can get damaged by the high heat. If you stop a car after driving, the lubricant and coolant oil also stops. This will cause the oil film breakage of the still running shaft and bearing and also the high heat of the turbine housing will transfer to center housing which cause the sludge.(heat soak back) If this sludge increase, the oil passage will get narrow and cause an even higher heat. Later, the sludge will get granular carbon and damage the bearing, seizure of the bearing and breaking the shaft. It's better to have an idling time after a drive. And if you can't have an idling like at a race, making the cooling system for center housing will prevent this problem.

Depending on where you live, it's not that hard to let it cool down and you will do it without thinking.

The only time it's a real issue is from flat out to switching the car straight off - and that's quite hard to do in real life

The only time I ever do anything different is motorway services - pretty much everywhere else I go has a few minutes 30mph on the approach anyway.

When I had a tuned Impreza I used to be concerned, but the RR doesn't get driven quite so hard

Keep your oil clean (and the coirect grade and quality, castrol in my ) and you won't have any problems. I change mine every 5000,

I have a van that has done somewhere over 200,000 miles now and I don't warm up or slowly cool down the turbo, I basically thash it everywhere it goes (and im sure my drivers do as ) and its going strong. For the first 150k I changed the oil every 10k and now I do it every 5 with fully synthetic, touch wood, no problems at all.

Mickey... You and i will never see eye to eye on anything i post on this site! You have made this perfectly clear!

If you were running a race car into the pits then YES that statement is correct but ITS A TDi RANGE ROVER FFS! Who in there right mind is going to sit there and let the car tick over for 10 mins beginning & ending of every journey! Do RR owners not have better, more important things to do with their lives?

One rule for all turbo applications isn't realistic. It's difficult to compare a small bore low compression petrol high revving compound setup with a larger bore diesel slower revving twin bank turbo setup. ______________________________
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