Do engines with turbo's need to idle before they are switched off?

[aliti]

Hi guys,

This might be a silly question, and it will show my lack of understanding of modern engines.
In the olden days, cars fitted with turbo's had engine timers fitted or the owner's allowed the engines to idle for a while after a run before the engines were switched off. I thought this was done to allow the turbo enough time to cool down and prelong it's life.

Do we with these modern turbo engines as fitted to the 118D, 120D, 123D and 135i need to allow them to idle after a run or can we just switch them off????

Thanks for your feedback and I do apologise if the question seems a silly one.

[AussieAlf]

Modern turbo engines run cooler. Most are water cooled, I dont have an authorative source at hand, but believe the 1-series turbos are all water cooled. I did let the MX-5 turbo idle for 30 secs after a freeway run for the first few months until a fellow club member (and Mazda dealer service manager who also owns a turbo MX-5) laughed at me and told me I was wasting valuable minutes of my life.

The BMW engines don't generally need a cool down period in normal driving - including Autobahn driving let alone aussie freeways at not too much above the speed limit. However, after a fiery session on the track I'd give any engine (turbo or NA) a few minutes of cool down.

A quick warning though, turbo timers are illegal in Victoria (something about leaving a motor vehicle running unattended). Many boy racers use them, though I've known a couple to get done.

What does the owners manual say?

Cheers,
Alf

[aliti]

Hi Alf,
Thanks for you feedback. I don't know what the owner's manual says. I don't get delivery of the vehicle to possibly end of next week.
I know of a few truck driver's with turbo diesel's that come into work and they always let their motor's idle for a while before they shut them down.
I therefore thought that I would ask the question.

[RadiuM]

All the turbo cars ive owned (about 6) I usually just drove the last couple of km's sedately and switch them off as per normal when I get to my destination and ive never had any issues at all.

with the 135i though, when you turn the car off you can hear an electric pump still cranking which I assume is the water pump continuing to push water through the pipes and taking out the heat after its just been told to stop running

I think it's alot more important to actually warm your car up first before any drive.

[BMW-NC]

BMW turbo engines are water cooled (the turbos of course as well). The radiator and water flow goes on after turning off the car.

So to sum it up, no need to "cool down" the car!

[sparoz]

BMW has the pump (or whatever it might be?) going if the temperature is above a certain range I believe. In hotter days, the 135i sometimes have that sound going for a while.

I know my 318i's fan came on when I had cracked water tank.

[banglemangle]

Fortunately, all 135s carry a spare hairdryer :-)

[taipan168]

Originally Posted by banglemangle

Fortunately, all 135s carry a spare hairdryer :-)

Not the newer ones

[BMW86]

Our cars run pretty hot during idle after a spirited run. It's better to keep the car moving at a consistent speed with the revs low. I actually find that our cars cool fairly quickly after shut down anyway so I always try to take the last few km's slow and shut down within a minute.