Hi,

Was in my mates glanza which reminded me, do I need to let the turbo cool down for 20//30secs? I know your meant to on petrols.

Does the same apply to diesels?

If so, possible to fit a timer? If not, just take it steady last few miles or sit and wait?

Liam.

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I was told (and always done it) after I park to leave the car running for at least 20 sec without touching the GO pedal before switching off It is not a big deal but apparently help the turbo to "recover" ..whatever this means

I dont always remember ! I try and be a bit lazy before switching off. Certainly don't go tanking if about then switching straight off having just put the car under load, or try not to.

I think its more important if you have been ragging it and pushing some load through the turbo, the concept is if you then shut off while its still spinning it will be starved of oil and thats where damage occurs worst.

I guess that could even happen then by blipping the throttle even, then switching off in the middle, is probably the worst you could do

Yeah I guess it you tend to slow down (as most of us have to) with b roads and such then it gives the turbo a bit more chance to cool down.

I've done 90k on the original turbo by the way (famous last words, best touch wood)

Yeah I go steady for last few miles to bring oil pressure down, then give it 30s or so at idle.

Although in terms of hybrids with 360 ball bearings is it still required to leave it idle for a while? Never been sure but I've carried on as before.

The last few minutes of your journey just take it steady and when you come to park up just let the car idle for 20 seconds then turn it off. Ive done this ever since ive had my car and have had no turbo problems... on 71K now (20k remapped)

I just ease off when i`m near home if i`v been fully gunning it. Timer would mean bypassing the immobiliser and a whole ballache with insurance.

Ive always done this too, but the other month i read that it was no good for the PD engine to be left idling?

The best thing to do is take it easy before you park up and let the engine idle for a few seconds, maybe a minute before shutting down. Remember that the turbo is working in the exhaust gases, which are bloomin' hot and spinning at over 100,000 rpm when you are giving it the full beans. If you don't give it time to slow and cool it will be spinning without oil being fed into it. Everytime that happens the oil will cook in the turbo and coke up the galleyways. Eventually the pipes will be coked up so much that there will not be enough oil supplied and the turbo will fail

Ian

I`v read that idling it to warm up is pointless as diesels are more efficient than petrols, but I cant see how it can bed for it.

Im not sure if its mad but I carefully drive the car til its up to temp as well, then once its closer to being warm oil etc Im ready to go for it !

Ive always done this too, but the other month i read that it was no good for the PD engine to be left idling?

But what if you're stuck in a traffic jam?!

The best thing to do is take it easy before you park up and let the engine idle for a few seconds, maybe a minute before shutting down. Remember that the turbo is working in the exhaust gases, which are bloomin' hot and spinning at over 100,000 rpm when you are giving it the full beans. If you don't give it time to slow and cool it will be spinning without oil being fed into it. Everytime that happens the oil will cook in the turbo and coke up the galleyways. Eventually the pipes will be coked up so much that there will not be enough oil supplied and the turbo will fail

Ian

Fully agree with Ian. My old B5 S4 with K03 turbos (RS4 had K04s which were much better) was notorious for blowing turbos as the oil-supply pipes weren't big and people used to rag them and then switch off. Audi forum-owners always suggested running off-boost for the last 5 minutes of your journey (ie running in vac rather than on positive boost) to let the turbo cool down to a normal operating temperature. Then let the car idle for at least 10 seconds to let the turbo spin down to idling speed. Don't forget, as soon as you turn off the engine, the oil stops being pumped round. So those with fantastically glowing turbos are just cooking the oil in those veins closest. Then, as Ian says, the veins will line with burnt oil and, after doing this time after time, you eventually starve it of oil, the bearings can't be lubricated, overheat and fail. I ran the car for well over 70k miles without a problem and I do believ this is because of it. Having a boost gauge helps of course.

I still warm the car through before driving hard and cool the turbo at the end of the journey. I then turn everything make turning the engine off the last thing before I shut the door after I've got out so it has maximum time spooling down. Prevention is most definitely better than cure.

Edited 21 March, 201214 yr by travs

Well letting my old PD130 engine idle for 20/30 secs before switching off, did it no harm at all. Managed 182,000 miles. Sold the turbo and noticed it was in amazing condition for its use

I tend to let mine idle on the drive for around 30 seconds before switching off..

But what if you're stuck in a traffic jam?!

On my commute home there is a set of traffic lights which hold me for around 2-3 minutes, and by this point the engine is warm, so I just turn it off for a wee bit.

In the 50,000 miles I've done in my PD130 I've never turned it off when I've come to some traffic lights or sat in traffic.

I usually let it idle for 30 secs or so before turning off if i've been booting it, or if Im arriving home (driving through a 30mph zone) I'll drive with it out of boost. Has worked for me so far!

IMO... Unless you've been booting it right up to your door there's no need to do anything other than turn off the car, lock it and leave it. Exhaust temps for diesels are far lower than petrol turbos and that is the primary concern when wondering if your turbo will live.

Even in my P1, unless it's the middle of summer and approaching 30 degrees, a gentle trundle home the last mile or two through the village works well enough for me to see the oil temps start to drop.

J.

IMO... Unless you've been booting it right up to your door there's no need to do anything other than turn off the car, lock it and leave it. Exhaust temps for diesels are far lower than petrol turbos and that is the primary concern when wondering if your turbo will live.

Agreed. I have never bothered on any of my turbo diesels, at most I only give it a few seconds of cooldown if its driven hard just before destination.

Wikipedia also suggest that coking is less of an issue on diesels due to the higher specification oils used.

Famous last words, right?

...cool the turbo at the end of the journey. I then turn everything make turning the engine off the last thing before I shut the door after I've got out so it has maximum time spooling down..

But then how can you depress the clutch when turning the engine off to reduce wear on the DMF?!

But then how can you depress the clutch when turning the engine off to reduce wear on the DMF?!

Can you point me in the direction of a good thread about prolonging the life of the DMF???

Good to see this topic about turbo cooldown. I drive like a grandad anyway so I'm sure it'll be fine but will be giving mine a bit of time to cool from now on before pulling out the key and walking away.

Well I was having a quick Google and depressing the clutch at start up and shut down seems to be a common tip, although can't find much in terms of solid evidence to back that up, although there does at least appear to be solid reasoning. Apparently there is some Italian white paper on it but I couldn't find it.

By far the most common tip is driving style though. Basically the DMF smooths out imbalances (i.e. pulses) in the torque to remove some of the classic diesel rattle and vibration, plus it makes things easier on the gearbox - so to minimise wear on the DMF avoid high torque situations at low revs. Don't sit on the clutch at traffic lights, don't move the car in slow traffic using solely the clutch, don't pull away in gears other than first, don't floor it below 2,000 revs in higher gears, avoid any situation where the engine "judders" etc

However I did find a

showing you exactly what and how the DMF does, and I always think an understanding of the mechanics elps you to treat components with more mechanical sympathy.

Edited 21 March, 201214 yr by ckyliu

But then how can you depress the clutch when turning the engine off to reduce wear on the DMF?!

What's a DMF?!?

Edit - that'll teach me for quick replying before reading everything. Now I just look like a tit. (Wait...NOW?)

Edited 10 April, 201214 yr by travs

Incidentally - even my old E36 328i had a dual-mass flywheel; they're not exclusively for diesels (although they maybe more applicable granted)

DMF are more commonly used on diesels to keep engine noise down. Althought in some vehicles it makes more noise from the vibration they can give off (sounds like a loose heat shield rattling)

Well I was having a quick Google and depressing the clutch at start up and shut down seems to be a common tip, although can't find much in terms of solid evidence to back that up, although there does at least appear to be solid reasoning. Apparently there is some Italian white paper on it but I couldn't find it.

Cant find anything on google about this. Is this true?