I was just wondering i havent even driven my car for a while but last time i was driving it was really hot out like about 100 degrees give or take a few degrees so i put the a/c on and you can actually see my stock water temp gauge go up at lights. The car drove fine though nothing wrong and when i shut the a/c it was fine. Put the a/c on and same thing. When i was done driving i let it idle about 2 mins and then left for like 1-15 mins then i turn the key on with the motor off the temp gauge was real high. i start the car and the gauge goes down. I just think this is weird cause i heard and read on here the stock gauge dont move until its to late but my motor is still tight. especially when its below 90. The only time my car felt alittle down on power was when i took this kid who is like 270lbs for a ride lol.

 

I think this is normal (but I'm not certain). Mine does this too. my aftermarket gauge reads fine (180*-200*) when I shut the car off, but then when I come back to the car in 15 mins or so, the temp gauge reads upwards of 220* or so, but immediately begins to come down. I think this is because when the car is off, the coolant isn't being moved through the radiator and cooling down. If there are adverse effects due to this, I am uncertain.

 

Its called heat soak. When you shut off the engine, everything under the hood starts absorbing the heat coming off the engine. This includes the radiator. When you start the car, the radiator has heated up, and the hot coolant circulates. This causes the high reading on the temp gauge until the coolant begins to cool off.

 

If it is happening at stop lights with the car on then you have a problem. Keep an eye on your temperature gauge. If it moves even a little bit then you generally have a problem. I drive around Miami with the A/C on and it never moves. Well I used to... my A/C compressor siezed up. It's ok for it to move a MM after a few hard pulls but if it moves up all the time then definetely check your cooling system. Including the Fans.

 

I remember the first time I cleaned my radiator/AC condensor (and oil coolers) after buying my car. I couldn't believe all the crap that came out. And my car was well cared for otherwise.
I was always taught to try the cheap things first. It may not have anything to do with your temp readings climbing at the light, but it couldn't hurt if you haven't done it, or done it in a while. Just a thought.

 

Sounds like your water temp guage had the linearization mod done.
The stock gauge doesn't move in small increments.

With the stock gauge it's only one of three stages
cold / normal / or boiling (buzzer going off, water boiling out, turn it off time)
Jack

 

Pardon my ignorance, but what is the Linearization Mod?

 

That mod makes the stock gauge work like a normal (linear) gauge.
Mazda's gauge was apparently designed to prevent owners from panic when
they would have noticed the temp gauge in the high zone.
So when the FD gauge climbs to the hot area, it's basically too late.
Same reasoning they used in not mounting a boost gauge. (What we don't know
won't hurt us).
The instructions for the linearization are somewhere on this site. Don't remember exactly where
Jack

 

That's seems to be the case. But for the FIRST TIME EVER I actually saw my temp gage move past center.

Happened monday, I was driving through inland california 100+ degree wheather. I had the ac on and glanced at the temp gauge (one of a trillion times that I did it on that trip) It was between the halfway point and the 3/4 point. First I thought "****! I've never seen that bitch move!" so I rolled the windows down, turned on the heater and the temp guage dropped back to center. Rolled them up again, turned my ac on and it didn't do it anymore. I'm thinking that at that moment I must've been traveling through an extreme hot spot (valley) so my temps rose.

 

HeHe, Owning one of these cars is like having a girlfriend that treats you like
****. You wonder why you put up with her.

Or it's like owning an old english sports car with it's unreliable electrics. Always wondering if you'll make it to your destination.
Every trip is an adventure. Those english cars were the first with intermittant wipers, intermittant lights, intermittant gauges ------------

 

The oil leaks on those cars were not intermittent

 

LOL, my friend's MG back in college was the first with ABS... no matter how hard you pushed on the brake petal, you couldn't lock it up. Now THAT was an adventure.

 

temp gauge mod here...

http://www.geocities.com/MotorCity/G...technical.html

I did mine. LOVE it! do you REALLY need numbers? I mean, REALLY? Isn't around 190F enough, as opposed to 194.5?

 

https://www.rx7club.com/showthread.p...ht=temperature

If you don't mind the cost of a separate guage, this might be easier.