Hi all

I'm new to the VRS and turbo cars and I'm wondering what everyone's turbo cooldown procedures are.

I know that old school turbos required the engine to be run for a while after being parked up so that oil could continue to be circulated whilst the turbo was winding down and cooling down (even after regular day to day driving) to prevent damage to the turbo. I assume this should still be done on modern tubo cars?

I've been letting my VRS run for a brief period after parking up before killing the engine - does everyone do this and what is the recommended cool down time?

I have never done this?

My Mk1 Octy is 8 years old, done 94'000 and never had a problem

Steve

You should always allow a period of time for oil cool down if you have been pushing the engine, if you drive economically for the last mile to your destination you shouldn’t need to worry about idle cool down.

This rule is for both petrol and diesel turbo's if you want to prolong the life of them and keep their bearings in tip top condition.

Not too sure if you need to worry as much on the newer cars, but I always let mine idle for about 5 seconds before switching off, unless I have driven tyres smoking onto the driveway - then it'll sit a bit longer. It doesn't hurt to wait a few seconds before switching off, but I think it is probably more important to let the engine fully warm up before gaffa taping your throttlle to the carpet, I never take mine above 3K RPM or make the engine do too much work until it has fully warmed up so that the metals and the oil get up to operating temp.

I'm now stranger to fast cars (in fact this is the slowest car I have had for a while!) but i'm new to turbos but I always ensure that the oil is up to temp before opening up the throttle. I guess the turbo thing is subjective; I can't imagine every day drivers (or the previous owner of my car) letting the engine cool down before shutting off the engine but I would imagine it is a practise that should be followed to ensure that the turbo is not damaged. 5 seconds really won't make any difference, I think if you are going to let it cool down it should be for 30 seconds plus unless as mentioned you have been driving off boost for the past mile or so.

Can anyone confirm at what RPM the turbo kicks in? The engine is so linear that I am having a hard time telling! It seems to pick up very well low down, well before 3500 rpm.

I'm now stranger to fast cars (in fact this is the slowest car I have had for a while!) but i'm new to turbos but I always ensure that the oil is up to temp before opening up the throttle. I guess the turbo thing is subjective; I can't imagine every day drivers (or the previous owner of my car) letting the engine cool down before shutting off the engine but I would imagine it is a practise that should be followed to ensure that the turbo is not damaged. 5 seconds really won't make any difference, I think if you are going to let it cool down it should be for 30 seconds plus unless as mentioned you have been driving off boost for the past mile or so.

Can anyone confirm at what RPM the turbo kicks in? The engine is so linear that I am having a hard time telling! It seems to pick up very well low down, well before 3500 rpm.

As I said controlled economical driving for the last mile should cool the oil in the turbo bearings, the turbo in the 2.0TFSI starts coming in really early probably around 1800 - 2000 rpm on a standard map if I remember rightly.

Thanks for that. It does imply that the turbo is always going to be spooling up, even under normal driving (1800 rpm is very low). Ideally in those situations you shouldn't need to keep the engine running to prevent bearing damage - This is after all and every day car and not some full on turbo car (i.e EVO) .

Has anyone ever heard of turbo problems (bearings or otherwise) with VRS's?

I've been letting my VRS run for a brief period after parking up before killing the engine - does everyone do this and what is the recommended cool down time?

Does it not say in the drivers' manual? It says 2 minutes if you've been pushing it for my non-vRS diesel Fabia.

As the F/L Octavia with Maxi-dot has an oil temperature reading, what should that read before switching off?

My 2005 TDi reads 84 or 85 degrees for the oil temperature once the engine is warmed up (This is using the climatronic readout as cars of that age even with maxidot AFAIK don't have this reading available on the dashboard) - strangely the temperature gauge, which presumably is the coolant temperature gets to 90 degrees while the oil temperature still reads in the low 70s. If the engine is pushed hard I've seen the oil temperature go to 86 degrees (The dashboard temperature gauge just sits dead centre at 90 all the time). The turbo spins down in a matter of seconds after the engine is turned off and AFAIK will be running full boost pressure on the standard engine map by about 1500 rpm. Diesel turbos tend to run colder but are used over a far wider rev range for the engine than petrol. Unless your house is at the end of a runway or something, normal residential area style driving will be more than enough to keep the turbo cool enough to switch off safely.

Edited 12 August, 201015 yr by psycholist

Not necessarily. If the turbo comes in at 2k rpm or below as has been mentioned it is easy to stray in to this territory even at low speeds. Turbos often spin for quite a while after coming off boost hence the reason why you need to keep the engine running so that the oil continues to circulate. I am hoping modern turbos wind down quicker but no one seems to know for sure. I would rather not park up at work or on my drive and leave the engine running for a short time so I'm hoping someone can say for once and for all!

It seems many diesel turbos seem to get knackered, I wonder if this could be one of the reasons?

This isn't about oil temp jlwah - the oil temp is more imporant before pushing the engine hard (and getting the turbo working). What I am referring to is how long the engine should be left running to continue circulating oil to the turbo to prevent damaging the turbo bearings. This is a problem for jap turbos for instance and can lead to some pretty serious problems if you turn the engine off to quickly after driving the car.

Hi Weyland, you are not the first and will definately not be the last to ask this question so here goes. The main reason for allowing cool down time with turbo cars is mainly that, to cool down, remember that the exhaust gases coming out of the engine can easily reach 600oC plus, I have seen many pictures of turbo engines on the test bench with their exhaust manifolds and turbos glowing red-hot. As you seem to know, by turning off the engine you are starving the turbo of its oil supply so the oil that is present around the turbo will quickly begin to cook, it will then evaporate the liquid proportion of the oil and leave carbon deposits in the oil galley, eventually these will restrict the oil flow enough to starve the bearings or bushes of sufficient oil so leading to seizure and turbo failure.

So on the subject of cool down, if you are taking it slowly on the last mile or so to your house, then allowing the engine to idle for about 20-30 seconds should be sufficient as you have not been putting a lot of heat into the turbo and it just really needs to slow down to idle, remember most turbos on small modern engines can reach in excess of 200,000 rpm when running full boost, if however you have been using the performance or have been cruising at high speed, on the motorway for instance and have just pulled into a services, then I would allow the engine to idle for around 2 minutes to allow the excess heat to be taken away from the turbo by the oil, and water if it is a water cooled turbo. I hope this helps alleviate your concerns.

Ian.