ernie9468

How many of you guys knew that after hard or extended driving with your 968 that Porsche suggest that you keep your engine running at increase idle at least two minutes before turning it off ,reason (to prevent excessive heat built up ).

dillon410021

I do this If I am on the boost!

Lemming

I do that at the track. Don't really push my street 968 that hard.

RajDatta

+1. The idea is to stop the oil from coking. Not an issue on NA cars as much as turbo's especially if they are only oil cooled. This was the case with older 911 turbo.

Thom

When the engine is idling stationary the output of the water pump will be inferior than when the engine is, say, running at a constant 2500 rpm in a moving car, and coolant temp will rise as there is no air flow to the radiator (unless the fans are running).

Any documentation on this supposedly official recommendation from Porsche?

Fox944

While i havnt read any documentation....from personal experiance (with all 3 of my front engine Porsches), if i ran the car hard and then shut it down right after....it would typically take 3-4 times the amount of cranks to re-start the car vs. if i let it idle for 1-2min before shut down.

Lemming

I guess I should have been more specific, after coming off track I often leave the car running but not necessarily at idle. If I let it idle, temperatures tend to rise, even with the fan on (I have it on a switch, not automatic). Thus, I have to run it above idle (2K) for a minute or so.

Now on my turbo diesel pickup, I have always let it idle after working it hard, not so much for engine temps but to allow the turbo to cool down.

ernie9468

Check page 25 off your 968 owner manual (under Stopping Engine) they specify letting the engine run at increase idle not idling stationary.

Thom

Well I just looked at the manuals I have, a 968 manual in French and a 944 S2/Turbo in German, and there is nothing that resembles even remotely to what you describe.
Maybe this is specific to US cars?

ernie9468

Well either it's in French or English the infos in your 968 manual should be the same,maybe in the French version it will be on another page number,page 25 of the english one is where it is I'm 100% sure.Could somebody here on the forum verify that please.

Thom

Well I'm not completely stupid, I also checked other pages

FRporscheman

Page 25, under "Stopping engine", has the following information:

"

• Turn key back to 0.

Do not stop engine immediately after hard or extended driving. Keep engine running at increased idle for about two minutes to prevent excessive heat buildup before turning off engine.
"


Interesting. I always knew this was called for on turbo cars but I didn't know I should also do this for my NAs. I think a "cool down lap" would be the best thing though.