Turbo cool-down question
 

I searched for an answer on this but came up empty.


I was told by the prior owner of my 2005 Turbo S that I needed to let the turbos cool down by letting the motor run for a few minutes at the end of a drive.

I remember we had to that years ago. But I thought modern turbo design and oil feed to the turbo bearings had eliminated that need.

I have been just turning off the motor when I get into the garage. But then on warm days, the engine fan will turn on and run for a few minutes.


Can any of you update me on this?


Thanks


PS Car runs perfectly. No issues. All stock except for drilled holes in OEM muffler.

Told to me by someone that re-builds turbos...Let the car idle for 90-120 seconds. This allows the oil to cool the turbos. Once you shut it off the oil no longer flows. No whether we have to worry about coking any more is debatable.

^ ..i would add only that under normal city driving conditions, no cool down is necessary. depending upon what "normal" mean to you of course. lol

pushing the car, yes. cool em down, as per above.

It indicates the cool down requirement in the manual of my '04 TT Cab. I will only not do it (so to speak) if I haven't had the boost level stay at 0 for at least 2 miles before getting to where I'm going. Otherwise I let the car idle. 2 minutes is not a long time to avoid possibility of very expensive problems down the road.

I figure the 5 minutes I have to drive @ 25mph through my neighborhood is plenty cool-down time.
Now, if you just pull off the track after a hard 20 minute session, that's a different story. That's when you let the car idle for 4-5 minutes and spray water (or an alcohol water mix if you have it) over the radiators and oil cooler up front.

Unless you came home, with your motor full of mineral 10w40 oil, at full boost level, then cut your engine and ran for your life, you do not need to waste any fuel on cooling your turbos.

I don't think it matters due to the location of the coolant expansion tank. It is at the highest point in the system so I think as long as the coolant is hot it will keep circulating up and back down till it cools off.

our turbo's are not water-cooled, oil only.
IMO, if no hard-boost in last five minutes of a drive then cool down is likely unnecessary...but cooler is better.
I always let mine cool, even if only for 20 seconds after a light drive; 1-2minutes after hard run. A minute of no-boost driving is also a great pre-idle cool down due to added airflow around turbo's.
Cheers,

No boost, I let it idle maybe 30sec or so, under boost 1-2min

I realize the turbos are oil cooled, but wouldn't the circulating water pull heat from the oil too as it is cooling?

My 2002 Owner's Manual says to let it cool down for a couple of minutes before turning the engine off so I do it everytime regardless of prior boost level or cruising speed. I know quite a few other turbo car owners who do the same thing. I trust that Porsche knows what they are doing and don't have some other agenda when recommending this cool down procedure.

When the engine is running-yes, when engine is off-no.

For the last couple minutes of your drive take it easy and keep it out of boost and your fine.

OK. Thanks for all of the comments.


I don't usually push it too hard. But the street up to my house is steep and I have to drive in first gear for about 1 minute to get up the hill. Usually not over 2500 rpm.


I think with my type of driving that I will let the motor run for about 1 minute after pulling into the parking spot in the garage.

i let mine idle just because i love to hear the turbos spinning even at idle!!