After you shut down an engine, temperature spikes because coolant is no longer flowing rapidly through it and the rad. This spike lasts several minutes and if the car was already a bit hot before you shut it down, gets well into overheat territory since there is no way to reject the heat. Running the fan eliminates this. In fact, because the FD is such a massive heat pump nightmare, Mazda set up the e-fans to run a little while after shutdown.

It also helps prevent heat soak at the track.

Yes, exactly. I originally did my writeup nearly 5 years ago because I was sick and tired of seeing the same misinformation and dangerous wiring everywhere. Sadly it does not seem to make much of a difference because few people actually research their decisions...

 

The water may get hotter but the engine isn't. There's no more heat being added from anywhere, but the heat from the metal engine parts is being conducted into the water, raising its temp. That's completely different to "overheating", and isn't doing any damage. The real problem from post-shutdown heat soak is heat being radiated off the engine and into all the rubber and plastic parts, which over time degrade as you'd expect.

 

Just to clarify: There is no benifite to running an E-fan after shut down of the engine? There is no degredation of parts beyond normal?

Wouldn't just turning off the engine and having the E-fan turn off be the same as with the stock fan system?

 

Exactly. With proper maintenance, you wont have to worry about those plastic parts or rubber hoses. On a 15+ year old car, the damage is already done so trying to prevent something that has already taken place wont do any good. Maintenance is the only preventive measure.

Yes. Since it has been this way for 15+ years on most models, what is to worry about? Most small "issues" are not issues at all and come from paranoia

 

you know, its funny, i run the flexilite black magic fan, and it works wonders!

peace

 

No one ever said running an electric fan would not work. In some cases, the e-fan will not work as efficient as the clutch fan.

Again, all this is covered.

 

Yes, I meant to say "coolant" instead of "engine". One of those rare moments were I overgeneralized instead of being too specific. The spike in coolant temperature is quite impressive from what I've measured. Well over 100 degrees as measured by the ECU for a few minutes after shutdown. A large water cooled turbo likely contributes to this. While I'm not worried about engine damage (though the coolant recover bottle fills up ) the whole engine bay becomes an oven with no airflow. Even a bit of airflow helps considerably.

It prevents the engine bay from baking all rubber components, including that wire harness that runs right over and past the turbocharger area. In addition if you are at a track (autocross, drag, etc.) then the engine bay heat soaks and the car is sluggish off the line.

Yep.

 

I do agree to some extent. I my self have watched my GReddy temp gauge climb after shutting down the car but I havn't see on my N/A, climb over 200.

As I stated before, if the proper maintenance is done, you wont have to worry.

 

Electric fan conversion was the first thought that came into my mind, I'm for sure gonna do it when I get the cash.

 

I don't see how blowing 70-80degC air off the radiator into the engine bay can make that much difference. There's just far to much residual heat in the engine. And once the coolant at your temp sensing point cools below the switch-off point, the fan's going to stop anyway, and there'll still be tons of radiant heat in the engine bay. All I see is a draining battery...