neoney

So my 8 only seems to turn its fans on at 102C, or 214F. I know they work, because they are LOUD at the speed they're working for, and the temp starts going down. Looking into my OBD2 scanner - temp goes up to 102C, fans go on, temp goes to 98C, fans go off. And up again. This kind of heat only happens when standing still.

I've decided to try and see what's wrong with it. Pushed the airbox and undertray away to see the fans, and even at 210F, they weren't moving a bit. I also heard no click, so I thought that it's probably the relay.

Well, I've removed fan 1 and fan 2, and tested them - they both work.

So, what's the next thing that could be wrong, if the fans only work in high speed mode, and the relays are fine? May the contacts for the relays be corroded? They were pretty hard to remove.

Meat Head

Try searching “www site Rx8club cooling fan trigger temperature “ in the Google option of search. Lots will come up. I’m thinking your temperatures are about right for stock ( my first search gave this: https://www.rx8club.com/series-i-tec...n-temp-161901/
).

You can also look up Fal420 fans if you want to lower temperatures since I think they come with an option to change trigger temperature. Or edit the temperature in MazdaEdit or VersaTune.

neoney

Yeah I've looked into the temps and that's why I'm suspicious. It says they should be low speed at 97C, high speed at 101C. They never go into low speed. They turn on only at 101C, immediately into high speed.

neoney

Okay, new info - shorting the fan relay #1 does nothing, and the passenger side fan does not spin when over 102C - only the drivers side one. I guess that means the motor is burnt out and I need to swap it?

SparklingFresca

Depending if you want to swap in a new OEM fan assembly or go aftermarket, the FAL420 seems to be the meta these days. Doing a search on the forum will get you good results on setting this up. Definitely look into getting the fans turned on earlier, there are numerous ways to accomplish this.