Car doesn't overheart.
Coolant light is on when u start the car in the morning.
then it comes of when the car reaches 180 Degrees.
the coolant in the reservoir and radiator is full.

I'll be doing a coolant flush next week to see if it helps.

 

Test the sensor at the top of the rad. It may be faulty, or there just might be a collection of bubbles around it.

 

might also be covered with junk, the sensor is very sensitive to grounding through the liquid. try checking and cleaning it.

 

Have you bleed the coolant system?

I did a flush and my light and buzzer would come on as soon as it warmed up a little until I bleed the system.

I think there is a FAQ on how to bleed the system someplace but can't seem to find it. If you do a google search for rx7 coolant bleed you'll find a few and most use a big yellow funnel.

What I did is:

Park car on a little upslope.

I made a funnel out of a 1.5 liter whiskey bottle. Cut bottom off, trimmed cap treads and wrapped with plastic electrical tape until it fit snuggly into the radiator filler.

Crimped or plug the overflow hose on the filler neck.

Filled the radiator and then put funnel in and put a couple inches of coolant into it.

Run car at idle and add coolant as needed. Think it is best to run until thermostat opens. Also should have heater on hot and no fan.

 

Thank you all. I'll check it out. I'll do the coolant bleed and clean up around there.

 

how do you actually check the sensor?

 

Remove the sensor, inspect it, and test it per the instructions in the FSM.

The Factory Service Manuals for all years of RX-7 (and many other rotary cars) can be downloaded for free here: Foxed.ca - Mazda RX-7 Manuals . They contain all common service information information and more, and are an essential tool for any sort of service work that needs to be performed on these cars.

Additionally, the Haynes service manual for the 1986 thru 1991 RX-7 (both turbo and NA) can be found at most local auto parts stores or purchased from any good bookstore (ISBN number 1 56392 007 7). It is only about $25 and is a great quick reference for things like this. Not only does it contain most of the information in the FSM condensed into an easy to read format, but it includes full wiring diagrams as well.

These manuals will answer 99% of service related questions for the car and if you intend to do your own repair work, you will need at least one of them. Preferably both, since the FSM is a free download. The Haynes is a good quick reference covering 99% of questions, while the FSMs show complete and detailed procedures.