I can respond to this point. I find typically, even with normal driving (some boost), that if I just park it and turn it off, the cooling fan comes on and I can hear the coolant bubbling in the radiator. This goes on for some time. If however, I let it idle until the fan comes on (highest temperature) and then continue to let it idle until it just goes off (lowest temperature), it does do this. Apparentlly idling DOES leave my engine cooler than when I just pull in to park, provided the period is not excessive.

 

Letting the engine run at no load either idling or at a slightly higher RPM after it's gotten very warm is a long-used method for stabilizing temperatures in the engine and cooling system. This no-load running reduces the temperatures at any hot spots, at least partially reducing the tendency of coolant temperature (and pressure in the system) to rise after shut-off. Letting the fan cycle once, as mentioned above assures that things have at least partially stabilized, so that's good.

VERY gentle driving just before shut-off accomplishes most of the same things.

Dave - veteran of driving overheating British sports cars in the '60's.

 

I do not agree with this procedure. Letting the car sit at idle until it reaches 220 degrees (stock point at which fans come on) seems really stupid. However, doing this makes it even more foolish to own a turbo timer, as it will not follow your procedure.

 

You're correct, adam c, that letting it go to 220F if it was not already close to that, is dumb.

I should have added in my last post, that I have a Miata thermoswitch, which, IIRC, makes the fans come on at ~205F.

Dave

 

Why would you shut the car off suddenly immediately after hard driving?

A. Professional thieves robbed the local branch of the Big City bank and you assisted the police in the resulting high speed chase which ended in a shoot-out, leaving you no time to cool down the car because you immediately had to take cover behind it. You then had to rush across town to save kids in a burning orphanage, shutting your car off just before before heading into the flames...

B. A serial killer took a young girl hostage and led you from phone booth to phone booth across town to see if you were bringing followed while delivering the ransom money. The only way to make it to the next phone on time was to keep the pedal to the floor and then immediately shut the car off so you could actually hear his next instructions...

C. The only brain surgeon in Smallville, U.S.A. was in a terrible car accident and the only way to save the governor's life was for you to beat your car all the way across town to scrub in on the surgery with only minutes to spare before lack of oxygen to the brain left him a drooling vegetable...

D. You don't have the maturity or self control to keep from flooring it all the way through your neighborhood just to show everyone how special you and your rotary exhaust note really are...

There's no excuse for not being able to drive sanely for a few minutes prior to arriving at your destination. Doing so eliminates the need to allow the car to cool down and absolutely eliminates the need for a turbo timer.

 

And also for allowing the car to warm up on cold mornings (or cool the cabin in summer heat). Go outside, start the car, turn on heater (or A/C in the summer), set the timer for maximum time (mine is 10 min.), shut the car off, lock the car and go back inside.

 

Only by men with narrow vision...

 

Yes, if you wait for the fans to bring down the coolant temps, you will be better off than just shutting down the engine anytime. And like DaveW said, it will dissipate heat from the hottest spots while idling.

But turbo timers don't do that, they just run for a specified period of time. So if the fans had just cycled off, and you park it, the timer could just as easily have let the coolant temps reach the threshold right before the fans kick on, making the situation worse.

Dave

 

Narrow vision can provide great detail, while wide vision provides specifics of nothing

 

So are you guys saying that you should not shut off the car after immediately driving hard?

 

Someone who doesn't move his car when his neighbors have been cutting down a tree next door could be accused of having narrow vision... among other things...

 

Only in the eye of the beholder... like I said, I use my timer for other purposes as well. We all agree since the 7 is a bit tempermental, it should be warmed to operating temps before spirited driving. I don't know how you drive your car, but for me this is not an Oldsmobile, so everytime I get in mine, I engage in spirited driving. How long do you sit and wait for your 7 to warm to operating temps? In the cold of winter? In the middle of summer? Me... no wait at all. Using my timer to run my car and shut off after a set time, when I decide to leave, I just hop in and go, nice and warm in the winter, cool and comfortable in the summer.

 

You stuck in a time warp... or maybe your life in worthy of nothing, so all you have is the past to hold on to.