So when driving my temps on my PFC commander stay between 85 and 99, depending on traffic conditions. However, when stopping and turning off the car, the temp steadily rises to around 110 degrees celsius! At what point do you worry about this or start making changes to fix this? What can you do?

 

You can do a fan mod to keep the fans running for a certain amount of time after you shut it off.

 

Does the water temp cool down quickly once the car is started again (water pump circulating coolant)? If so I wouldn't worry about it. It's normal.

 

Also if you can get your hands on a datalogit you can set the fans to come on at lower temps. My car stays 89 or lower until I shut it off. It "heatsoaks" for lack of better terms up to about 98, but when I start it again it cools back down to 88 or so within a few seconds.

Hope it helps.

 

Heatsoak is crazy in our cars. moreso if you drove aggressively prior to shutdown or if there's hot weather.

One time I went to a rest stop off a highway to use the atm and I literally took no less than 5 min. Temps went up like 30f. this was in summer though.

 

there was a fan relay recall which added a circuit to turn on the fans with the car off. you could check to see if it was ever done or applies to your VIN by calling the mazda customer service center. you can alternately replace the backup water sensor on the back of the water pump with an FC one which should turn on the auxiliary relay at around 100c instead of 110, iirc this applies to the fans while the engine is off as well.

 

Don't worry about it. Even if it does get high, the temps come down quick anyway. Try not to drive to aggresively when you are close to the destination.

 

Will definely call Mazda about that one. Thanks!

I also have a turbo timer. I guess I'll set that to run longer too.

The temps do drop fairly quickly once I start the car again.

 

You're correct, and the temps are 97 and 107