Just passing the time reading the manual and came across instructions for stopping the engine. Apparently after hard or extended driving the engine should be run at an increased idle for around 2 minutes to prevent excessive heat build-up.

 

I read that also. I understood "hard driving" to mean driving like driving during a track day. I'm not sure what is meant by extended driving. I know putting many hours in on a highway is actually easy on an engine. I wonder if it's lawyer speak?

Matt

 

When I used to drive a turbo I was extra careful to fully 'cool down' the engine before just switching it off. I needed to do that more if running conventional (not synthetic) oil and if I was doing spirited driving that really heated up the turbocharger,--I essentially had to to avoid coking up the bearings. I don't think that situation applies so much to the 997,--particularly since we run synthetics in them all the time. Porsche is being ultraconservative to remind people not to be out tracking their cars and after several hot laps simply coming in and shutting her off. That's why we use cool down laps,--both for the brakes and the engines. With my air-cooled 911 I used to also pop the engine lid, too, to help out with cooling, actually placing a large box-fan in the opening to suck the heat out. This stuff is absolutely not an issue with these new waterboxers!

Dan

 

Do it all the time, cars, boats, chainsaws, you name it. Should let them idle for a few minutes before shut down if they've been under load and revved up high for several minutes or longer.

 

On the road I find running temps only fluctuate 20-30 deg between cruising and pushing it. On a race track there may be issues here. I suppose if the temp gauge reads abnormally high you might want to let it cool down.

 

hard driving and extended driving heat soak all the parts. to bleed out the heat and prevent bearing coking it is generally a good idea after extended driving on the highway as well. i do it in all of my cars even the blazer beater.

 

If on the track this is the purpose of the cool downlap.

 

I let my baby warm down after each time I have it out for a long run.

Jay

 

I've noticed (now that it's warming up a bit here in the Midwest) that the engine compartment cooling fan will be running when I pull into the garage. Switching off the engine stops the fan - so i just let her idle for a minute, until the fan shuts off on its own.

No turbo bearings on the C4S <g> - but it's probably not a bad idea to get temps to runtime nominal before switching off the master...

Just MHO,

-don

 

The last two miles to my house are residential so I cruise along at a steady 35 - 40 (35 speed limit) running around 2200 - 3000 RPM's. I hope that is enough, because I do take out my car and drive it hard on a fun road near my house.

 

The last mile to my garage is in second gear. Normally, park and leave the garage door open for proper ventilation until the car cools for a minimum of 30 minutes. On HOT days over 90 degrees, I'll run my garage fan with the garage door open for a minimum of one hour. Its habits and piece of mind from my 964 and 993 ownership; I figured it worked since I have never experience premature valve guide wear (go figure).

 

Warm up and cool down. I do both. I just don't push it starting off or at the end.

 

I forgot to mention taking the belly pan off if you have it on will minimize excessive engine heat and damage to the valve guides (premature valve guide damage). This applies to the 964 and 993, but if you have the belly pan, quick take it off! (IMO)