On my DSM, I'm used to seeing 185-190 water temps and nothing higher, even on a hot day in stop and go traffic. I just installed a water temp gauge in my FD this weekend and drove it to work this morning. Once the car warms up to about 185 degrees it seems all good, until I got into some stop and go driving on the highway. It was a cool ~40F morning and the temps went up to over 220 and that scared the crap out of me! I thought my car was overheating for sure, but the stocker temp gauge never moved past the middle position the whole time. Once I got rolling again the temps came back down. I searched and found that the fans don't come on till ~226F. That seems really bad to me. Please tell me this is normal behavior and that I shouldn't panic. This is on a stock radiator, though I have a koyo radiator waiting to be installed.

 

where did you install the temp?

 

T-stat housing -- yea the gauge doesn't have any reading till the tstat opens, but I replaced that only a few weeks ago so no worries there.

Right next to the filler neck/cap there's a plug which I removed, drilled out, tapped, and installed the probe into, then screwed the plug back in with some RTV on the top side to make sure it seals nice. The only problem with this setup was that a cap with "wings" won't clear the probe. But a round cap has no problems.

 

sounds normal to me. you can turn on your parking lights and have the fans come on around 210f or you can turn on your a/c when you feel like it to activate the fans. theres a lot you can do from switching out the thermostat to rigging a fan switch. it has been covered extensively here in the forums.

 

 

It is basically normal. The cars tend to get quite hot in traffic, even on cold days.
The stock settings for the fans are to come on at 221 and increase speed at 226.
Now having said that, most people would agree that it's not the best design on the Mazda engineers part and most people work something out to get the fans to come on earlier.

You can replace the thermos switch with the FC part and that would trigger the fans at 203f (95c). You could install a manual switch (do a search for "fan switch").
If you have a PFC using the datalogit you can set the fan setting.
On some cars turning the parking lights on will cause the fans to come on at around 207f.

On another note, the stock gauge is pretty useless. It's not linear, and has a pretty wide center range. Some won't budge until you hit well over 230 degrees. Mine seems to be a bit of an exception, it moves at the same moment the fans kick on, 221 measured with my aftermarket temp gauge.

Hope this helps.