I have done a quick search with no luck so if I missed it please point me to the thread that talks about this.

I have noticed that when the car shuts down the temp goes through the roof. If you shut the car down with a temp of about 90-94 C, wait a few minutes, then turn the key to "accessories on" the temp could read upwards of 110 C which I feel is too hot. This is the same if you start the car too. I am asking what temps other FD owners see after they shut the car down?

I will soon be hooking my fans into the turbo timer, so that when I set it to turn off the car it will run the fans for another 5 minutes after the engine shuts down. This is just to move air under the engine bay. I also pop my hood for as long as I can, depending on where I park. I hope my turbo time can do that.

 

Also what do you guys do about the rising temps after shutdown?

 

This is normal. If I pull into my house after a hard drive or after stop-and-go traffic, I'll run the fans for 10 minutes or so (with ignition to "on" but not running). I've noticed that my post-shutdown temps rarely exceed 100C by doing this, even with the hood closed.

I think it's nothing to be paranoid about, it's normal for these cars. For normal daily driving, I just shut the car off and go....

 

If you start the car up after temps climb that high, and watch the temps, you'll notice them drop quickly down to 90C or so. The thermostat stays closed while the car is off so the coolant in the engine just sits and heat soaks, but as soon as you start it the t-stat opens and lowers temps almost immediately.

 

This is normal for any car. After shut down the coolant is not circulating and so what is in the engine just gets hotter and hotter.

Without knowing it you have proven that the crazies who think that coolant temps go down via convection after shutdown are, in fact, crazies

Crazy #1


Crazy #2

 

The thermostat stays open as long as the coolant around it is hot enough to keep it open. The thermostat has no care if the engine is running or the water is circulating or not, it just knows when it reaches its opening temp it opens. If the engine is off but water temp still high enough to keep the thermostat open, the thermostat is open. That's why we test thermostats in boiling water on the stove. All the thermostat knows is how hot it is; it's too "dumb" to know anything else.

The reason the temps drop after you restart the engine is because the coolant in the motor was stuck there at shutdown and heat soaks. The coolant in the radiator meanwhile has had a chance to drop in temp. As soon as you start back up the cooler air from the radiator gets pumped into the block and voila; the coolant temp in the block drops.

That's the reason I like the idea of an electric water pump so much. After shutdown the pump and fans could run and really bring coolant temps down quickly rather than heat soaking. It would work great at the autox during these hot Texas summers

 

The engine doesn't get any hotter after shutdown. There is no heat source any more. After shutdown, the hot engine heats up everything around it, making it feel like the engine is hotter.

If you don't like the heat, soaking your engine compartment, do the fan mod. You can run your fans for 10 minutes after shutdown. I do it all the time. I feel that it will extend the life of my rubber and plastic components by not cooking them after every drive.

http://www.scuderiaciriani.com/rx7/fan_mod.html

 

Thanks for all the feed back and point me in the direction of other threads.

I knew that the engine compartment would heat up due to no air moving over the car and the fans not running. I know that is normal for any car. I just wanted to know if this could be harmful and if there was more I could do about. I would hate to have my housing warp due to heat soaking. It looks like there is something I can do to help lower the temps after shutdown. I will modify my fans to stay on for a while after the engine shuts down. Thanks again

 

get a vented hood

 

get a vented hood

 

An electric pump with sufficient volume capacity (not just pressure) would be pulling a lot of amps. I'm wondering if the battery's reserve capacity would be able to handle both the water pump and two big fan motors for a sufficient period of time.

 

I have no idea. I have not looked into seeing what the draw of a pump would be, but I would thing 5-10 mins should be safe for all but the smallest batteries.