Running the engine before stopping engine

[mkimber]

The owner's manual for my '87 Carrera says: "Do not stop engine immediately after hard or extended driving. Keep engine running at increased idle for about two minutes to prevent excessive heat build-up before turning off engine."

Does any one besides me do this?

I am starting to get some strange looks from my family and neighbors when they see just sitting in my car for two minutes after pulling into the garage.

[masraum]

I used to run mine for 10-20 secs, but then I generally didn't race into the neighborhood at 6000 in 4th either.

I think this would be more like after driving on the autobahn at 130 or running a couple of laps at a DE, not your average around town, even if you redline the thing. Don't turn the car off if you've been stuck in traffic and the heat's way up either.

I found that if I ran the car for 10-20 secs before shutting it off that I had nearly no instances of smoke on startup, but if I shut the engine down immediately the puff of smoke on startup was much more prevalent.

[KNS]

Does not sound like a bad idea to me. Air cooled piston engines found on airplanes (Lycomings, etc) require a cool down period for the cylinder head temp to come down. I always let the engine idle for a minute or two to let the temps stabilise after a long, hot drive.

[svandamme]

i think it's safe to assume , that most "road" drivers , do not redline it right up to the last second, it's not like you can frigging gunn it , righ into the parking lot.... at least not if you have some decent social behaviour , the place where you park you're 911, is the place where you behave, that's the last place you wanna p!ss off anybody...

sure , if you have a track day, it might be usefull , to let it idle a bit after you came to a screeeching halt in you're pit box... but i'm sure with normal , city driving, you'de be hard pressed to drive like Jacky Ickx and cook your engine during your parking maneuvres... unless off course you have some serious bad driving habits.

[mkimber]

I love this board. Not only do I learn, but I get a few laughs in the process.

I think I am going to follow masraum's lead: 10-20 seconds before shutting down. The neighbors won't have time to roll their eyes or shake their heads in confusion.

[TerryH]

I thought idling can cause a motor to run hot. So it's 100 degrees outside and you've been sitting in traffic and the motor gets pretty warm, you're supposed to let it idle and heat for an additional 2 minutes before turning it off?

I would think they would recommend driving around at low rpm for 2 minutes. At least then there is additional air flow.

[Tricky D]

If it's running warmer than normal, let it idle for a few minutes to cool down.

If the temperature is normal, shut it down.

FWIW, I've never had to idle my car for cooling, either after a track session or a drive around town.

[jasonlee]

I let mine idle for a minute or so after driving for any thing more than 20 minutes. By doing so it has elimiated my puff in the morning start up. It's habit I guess, I used to own a turbo vehicle and would always wait a minute to let the turbo spool down, Just my $0.02

[NY65912]

A cool down period is just as important as warming up an engine. I was told this by a Mack diesel mechanic of high repute. I always run any engine for a few minutes before shutdown, even the '00 1.8T New Beetle of my son's manual says to do so.

[cab83_750]

I used to do this on the turbo I had. Sometimes, 2 minutes could feel 'f o r e v e r..........!'

[livi]

What masraum said. I let it idle for 20 - 30 sec, mostly to let the oil pump back into the oil tank - minimizing smoke on upstart.