Ok here is the situation as best as i remember:

I was going into the city today so before i left i washed my car, checked the oil and coolant. The oil was just a shade under full, and the coolant was above the full mark in the resevoir and above the veins in the radiator.

I drove Highway to the city (with A/C on), drove around in the city (with A/C off), and then started driving highway home. The temperature was at or below half with A/C OFF, and slightly above half with A/C ON.

On the way home (A/C ON, temp normal for A/C), after about 30 minutes there was a truck wiegh station and i decided to weigh my car just for the heck of it. I pulled off the highway and just as i ws pulling onto the scale my "Add coolant" light buzzer went off and my temp was slightly higher than normal but not dangerous, so i pulled up turned off the car and opened the hood. I checked the coolant in the resevoir and it was slightly higher than when i checked it before i left.

At this point i was close enough to home that i figure i could make it(i turned the A/C off).

I drove about 2 minutes and the coolant light went on again but this time my temp skyrocketed. I immediately pulled over and shut it off before the temp hit the"H". I poped the hood and i heard some kind of hissing/boiling sound coming from the A/C piping, and some steam coming out of the coolant resevoir overflow tube. I stuck my head under the hood and the engine bay didn't even seem that warm, so i felt the intake manifold, warm to the touch, normally i'd burn the skin off my hand if i did that right after highway driving. I checked under the car, nothing dripping or leaking.

I'm really baffled but the only things i could come up with are:

-I don't think the rad is sucking coolant out of the resevoir, just putting it in. Maybe getting a new rad cap could help??
-Maybe the temp sensor is malfunctioning?

Any assistance is much appreciated.

 

Didn't actually read the whole thing, but this should at least help: http://aaroncake.net/RX-7/cooling.htm

 

is it possible that my temp guage or something on the ECU is fritzing out?

 

Any other suggestons?

 

Have you ever searched for any threads pertaining to overheating issues?

Do you have:

- Functioning OEM thermostat?
- Functioning OEM rad cap?
- Belly pan?
- Two belts on the water pump?
- Clean and clear rad with a good core?
- Clean and clear condensor?
- Functioning clutch fan or comparable e-fan?

With all these items in place you shouldn't run into any cooling issues - other than perhaps during a tracking session of sustained high RPM where the water pump caviation coupled with small capacity of the OE rad creates high coolant temps.

If you do have all of those items, I would suggest doing the coolant seal test

 

Where would i find the thermostat?
How do i know if my rad cap is functioning correctly?

 

Well, Your cooling system lost a lot of coolant to some where and air entered.

Air == instant hot temps.

I'm just going to blurt out "Coolant seal failure" from hearing the resevoir was higher than previous.

That's pretty much how my car died.
Driving on highway for 45+ minutes. Get off highway and all of a sudden the car burps coolant out at a stop light.
I drive for a minute and then I see the temp gauge jump through the roof.


So yeah,
Top off your car completely so there are absolutely no air bubble and replace your rad cap. If it still purges into the resevoir then it's most likeyl blown.

 

thermostat is in the water pump neck...

if you even question the rad cap just get another new one - they're dirt cheap.

 

well how much did the car weigh

 

it was in Kilograms....1330 total, 640 front axle, didn't weigh the back axle cause that's when the coolant light went on.