Just ran my car around the block, testing to see when my fans come on and shut off with the miata thermo switch. I have a cyberdene digital gauge with the sender tapped into the filler neck right in front of the thermostat. My gauge seems to run about 5 degrees high. Drove it shortly, parked it with it running. Gauge showed 212, fans came on, then it steadily climbed to 225, the fans shut off, then it fell to 208, then started warming back up to 212 where the fans came on again, the it started steadily rising back to 220 before I shut it down. What the hell??

thanks

 

wait, when the fans were on, the car heated up, and when they were off, the car cooled down?

 

yep....crazy **** I tell you, ccrrrraaazzzzzyyyyyyy ****!

 

Only reason I can think the temp would rise is that the fans are pushing hot air onto the sensor... But I doubt that's it.. Dunno

 

are you sure your thermostat is good.is it facing the right way?

 

Is it possible to install it the wrong way? Just curious!

 

if you wired them wrong the fan will turn the opposite way their supposed to go, so instead of cooling they will heat your car.

 

same **** happend to me when i bought my car. The temps went up higher when the fans kicked in, (remember i was telling you that long time a go Justin)

Well it turned out to be my thermostat. I bought the one from the diller 180 degrees and now it works fine.

 

I just installed a new thermostat and put in in the right way, pointing towards the front, spring to the rear. I am the second owner of the car and the first owner didn't do a damn thing to it, so I don't know how the fans could be mis-wired unless they came from the factory like that
How can I check to see if they are wired correctly?

 

i cant remember if you can install it backwards or not but if its old,replace it.i've seen weird **** happen from bad thermostats and our systems are more complex than most.or maybe its that miata switch.put the stock one back on and check it

 

Turn your key and your A/C on, it doesn't matter if your car is running or not. Open the hood and make sure that the fans are pulling air INTO the engine bay, not pushing it out the front.

 

There is no way that your fans are blowing the wrong way. Did you use a Mazda thermostat? If not, I suggest you get one, and install it. Sounds like a t-stat problem to me.

 

I didn't use a Mazda OEM thermostat, I bought one at a local autoparts store few weeks ago, a 185F one. Hell, how can there thermo be any better when the car comes with a piece of %^$ radiator cap? I was having the same problems which is why I got a new thermostat to begin with. I put both the new one and the stock one in a pot of hot water and they both opened up at about the same time, the stock one didn't open as far though

 

how would this be a thermostat problem though, if the temp rises when the fans come on. I'm not trying to be an ***, just wondering if there is something I am not considering,

 

if your tstat wasnt opening until 225 the temps would rise even if your fans were on.its measuring temps at the tstat not the radiator.do your temps drop like a rock immediately after the fans shut off?if so, thats the temp your tstat is opening.

 

Believe it or not, Mazda is the ONLY game when it comes to thermostats. I've seen parts store thermostats fail in only a month! I don't know why, but they consistently have problems. Get a Mazda thermostat! Most dealers have them in stock, and they come with a new rubber gasket as well.

Dale

 

ive seen cyberdine gauges with varying readings due to fluctuations in the voltage either from the sender or the power/ground that powers it. the fans are a huge drain on your electrical system. check your voltage with the fans on and off. use a mechanical gauge for water temp or borrow someones infrared for symplicity to be sure the cyberdine is reading correctly.
the difference between factory t-stat and after market is not neccesarilly when it opens but how much it flows, that can make a big difference in cooling efficiency. the mazda ones were designed for a rotary not a piston engine

 

try running the fan constantly (from cold to warm) and then check to see how high it goes.....

 

why would the fans switch back off at 225?

 

ok, I see what some of you are saying, that maybe when the fans come on, the voltage from the fans is affecting the reading on the temp gauge by affecting the voltage in the wire coming from the sender, right?
Well how would I check that?

 

idea, the power for the gauge is currently coming from a tapped fuse under the dash, I could wire it directly to the battery and see if that helps, or run the car with the gauge powered by a totally seperate battery to see what happens.