[bimdaddy]

After some aggressive runs, I usually take it easy the last 1-2 miles to give the oil time to cool off the turbos. I haven't had a turbo car since my 85 Isuzu Impulse Turbo 1st gen. Back then, shutting down immediately after a hard run can cause the oil to cook on you turbos = early turbo death. With today's advance tech, not sure if you still have to do that, but I always do.

[youngbuck]

I'm curious to hear feedback on this topic. I have heard similar statements before.

-YB

[e90AW335i]

I believe the car has a "timer" built in and will automatically run some accessories for a minute or two after you shut it down. Regardless, it can not hurt to let them cool....

[boosted305]

Originally Posted by e90AW335i

I believe the car has a "timer" built in and will automatically run some accessories for a minute or two after you shut it down. Regardless, it can not hurt to let them cool....

Unfortunately that is only the water pump which will continue to circulate water after the car is off....

it will probably minimize the damage, but nevertheless, the oil is still stopped in the bearings and cooking,

I always cool down, and if, after I turn the car off, I still hear the water pump going, I turn the car back on and let the oil circulate until it cools down

[e90AW335i]

Originally Posted by boosted305

Unfortunately that is only the water pump which will continue to circulate water after the car is off....

it will probably minimize the damage, but nevertheless, the oil is still stopped in the bearings and cooking,

I always cool down, and if, after I turn the car off, I still hear the water pump going, I turn the car back on and let the oil circulate until it cools down

Thanks for the clarification....

[bimdaddy]

I never installed it, but back in the day, my buddies used to install turbo timers to allow the engine to keep running for a certain minute after you shut off ignition. But back to our e90, I never hear anything running after shutting off.

[e46e92love]

My mechanic suggested that every-time I stop that I leave it running for 15 secs or slightly longer to make sure oil is being forced through the turbos as they slowing stop turning. The turbine section can accelerate upwards of 200,000 rpms and when you turn your car off it the turbos are still rotating they are slowing down with no oil moving through them, and that can kill a turbo, especially the bearings.

[5soko]

i never let my car cool down.. btw i hear my E-coolant pump come on after i drive. its realli realli quiet.

[1clean335i]

yea, i take it easy the last few miles and let it idle for about half a minute or so then i shut it off...

[boosted305]

Originally Posted by 5sokol335icoupe

i never let my car cool down.. btw i hear my E-coolant pump come on after i drive. its realli realli quiet.

you might want to adopt a new philosophy!

[A418t81]

No need to idle and let your turbos cool unless you just got done beating on the car and came to an immediate stop. The turbos are water cooled which saves the oil in the bearings from coking. Rule of thumb is take it easy last couple of miles before your house and thats more than sufficient. If the car is warm, the coolant pump is going to run anyway and that circulates coolant through the turbos (but coolant circulates through the cartridge even when its off due to the convection effect of the coolant in the turbo).

[sandyeggo325i]

turbo timer?

[My1stbimmer]

At times I could hear ther turbo's still spooling after I shut my car down. Now I sit in my car up to a minute and wait untill I feel as though the engine isn't under any strain before I shut it off. It's probably best to give them sometime to cool. I drive turbo charged trucks for a living and the shopped that repairs them complained to our supervisiors that we were shutting down the trucks to soon after we came back from runs. Guess they noticed the gunked up oil too.

[san~man]

Originally Posted by 1clean335i

yea, i take it easy the last few miles and let it idle for about half a minute or so then i shut it off...

That's the same advice my friend who's a mechanic at BMW gave me. Let the car sit and idle for 30 seconds to a minute after spirited driving.

[A418t81]

Again, oil coking is not an issue on modern water cooled turbos. Back in the 80s, and even early 90s, most turbos were only oil cooled. It was much more imperative that the oil flow continue until the cartridge was cool enough to prevent the oil from boiling back out of the turbo and forming a thick sludge (coking) which would both starve the bearings of oil and contaminate them. This was just for normal driving.

Like I said above, now-a-days, no need to let the car idle unless you've been hammering on it recently. Driving it easily for a mile or two and maybe 15-30 sec of cool down after a hard run is all that is needed.

[bimdaddy]

Can anyone else confirm that our turbos are water cooled vs oil cooled? I've never heard of water cooled turbos, but again I don't claim to know it all. See you learn somethin' new everyday

[A418t81]

Our turbos are both water and oil cooled.

[5soko]

Originally Posted by boosted305

you might want to adopt a new philosophy!

i guess bmw's isnt good enough

[oddjob2021]

most new cars have systems which monitor this and prevent it... i would assume by now, that after having this issue in the past with ignorant drivers that they would have fixed this with an automatic motion after you shut off... if not... cars havnt really progressed in this mode. lol

[denlin68]

My BMW Delievery Guy told me after a long run , u might want to wait 15-30 seconds before turning off the engine thats all.

[bimdaddy]

Originally Posted by Brisk

dont really let my cool off ever.
these are ball bearing, twin scroll turbos that run synthetic oil in them. this alone goes along way in helping the turbos last longer

with water cooled turbos, the water actually goes around the bearing, cooling it so the oil does not cook inside. but this has marginal effect once the car is shut off. in the N54's case, this water cooling continues to flow and does not allow the oil to cook even when the engine is shut off.
bmw is not stupid guys.

Guess I'm still old-school. I guess it's just peace of mind for me, but I feel better letting it idle for a minute before shutdown. Can you hear any kind of pump running after shutdown? Maybe I'm not listening closely.....I don't hear any pump or motor noise.

[LambOfGod]

I usually spend the last part of my drive to cool the car down...driving it easy as it were. Sitting in the garage on a 90F day isn't going to help cool things down to much if you know what I mean. I think it is best to have the car moving plus don't run it hard the last couple miles of your commute. I've owned 4 turbo charged cars and this has worked for me.