Autozone Wells TU146 $33

As you can see in the pics it has stamped numbers:

97deg 92deg 03k(?) 5189(?) Italy

I assume those are the temp ratings (206.6 F and 197.6 F), maybe k-ohms and serial#

One question, do I still need the fan mod after installing this or will the switch take care of my fans with no other mod?

 

I believe this will turn your fans on at about 99deg c, not sure on that though...

 

You won't need to mod your fans, unless you really feel you need to have a switch to play with. If that's the case, get a girlfriend instead

I suggest getting a small crimp connector and splicing it onto the end of the original thermoswitch wire. Bend it so it has good solid engagement - Ray gave me a little connector when I bought an OEM miata t/s and it wasn't very good.

Dave

 

Hey could you do an instal write up when you finish putting it in?

 

The miata switch will work just like the old switch, except the fans will come on about 10* sooner. If you want anything else, you will have to do a fan mod.

 

i dont understand this modification,,, why didnt mazda put a cooler thermo switch in themselves

 

Also use some sensor safe silicone to hold that connector in place.

 

Thats a good question. You would think that they should have done it. I can't think of any reason that they didn't do it.

 

Well, my fans have never come on after shut down but they will if I leave the ignition in the ON position. This is what I do everytime I get back home, I leave the car in the ON position until the fans come on and shut off (about 10mins). I thought this was due to the switch rating of 221 F is not reached until after the shutdown heat soak period.

I thought the Miata switch will activate them since it's a lower temp (207 instead of 221) ??? That's all I want...

 

There really isn't anything to it. You are just replacing the stock sensor with this one. The only tricky part is what you use to connect the new sensor. You can just use a spade connector (cut off the stock connector and solder on the space connector). The wires will most likely be brittle so you won't have to worry about cutting off the old connector, it will probably fall off.

Running the fans when the car is off doesn't do a whole heck of a lot. The car isn't moving so no fresh car is coming across the radiator (that and the water pump isn't on either).

 

thats why you should get a turbo timer! and leave the fans on while the car is at idle for a couple minutes.

 

Hotter engines run more efficient, and Mazda originally intended the RX-7 cooling system to operate at a higher pressure (so it could run hotter without boiling over & overheating). But due to some problems with hoses cracking/bursting from the pressure (supposedly caused by people not allowing the car to cool down before shutting off the motor), they lowered the pressure of the cooling system from 1.3 bar >>0.9 bar. This lowers the boiling point of the coolant mixture, which is, in my opinion, part of the reason why so many of our cars overheat.

But back to the topic, yes, a cooler thermoswitch should have been part of the cooling system recall. Oops.

-s-

 

Isnt it behind the coolant filler neck? I guess I just need a pic of its location.

 

Even then you don't have air flowing over the radiator since the car isn't moving.

Turbo times are to keep oil moving so it won't coke on a hot turbo. The stock turbos are water cooled so they don't have this problem.

 

Yes, it's on the firewall side of the filler neck. Unless you have girly hands, you'll have to remove the alternator to get room to access it.

 

Neit:

My fans have only come on once after shutdown. I never really run my car all that hard anyway, but I also have a downpipe, which I believe keeps temps low to begin with. I found, like yourself, that I can get the fans to come on by turning the ignition switch to on. It does seem to do some good if they stay on for 7-10 minutes. But then, I've discovered I can achieve about the same thing by just lifting the hood and letting the heat naturally rise off the engine bay when I come home at night. I really need to get a water and oil temperature gauge to monitor this more closely. I'm looking forward to your experience with the Miata switch. By the way, what is the order number for the Mazda part? My local Mazda dealership had no idea what I was talking about when I attempted to order one. Is the Wells unit comparable?

 

The part number is: N350-18-840

 

Hey sorry to hijack the thread.... but, mahjik, does that mean that I can change it without removing the filler neck? Is it a pita to get to?

 

Yes and Yes.

 

wait, does that mean the all I have to remove is the altenator and I can get to it? Thanks again for your help Mahjik!!

 

It's been a while since I did the install. You'll definitely need to remove the alternator and maybe get the pressure chamber out of the way. Basically, once you remove the alternator, remove anything else that is in your way of the sensor.

 

Thanks Man....

 

What store is the part number for? Thanks...

 

That is the Mazda part number. If you go to an auto store, they should be able to cross reference the Mazda number.

 

Thank you very much!!