I just purchased this car over the winter(91 rx7 NA), the past few days have been the first days over 90degrees outside, while driving at 55-60mpg, the temp gauge looked fine, but when i accelerated above 65-70, i noticed the temp gauge start to climb. I checked my fluids, and they are fine, my first thought is that maybe the radiator isn't working properly but wasn't getting as hot because of the cooler weather. Just curious what other opinions were.

 

Thermostat or coolant seals....... antifreeze to distilled water ratio might be off too.

I would flush the system, and put a new thermostat in.

Is it blowing sweet tasting smoke?

john ny

 

I may try a thermostat this weekend, but there is no sweet smell to the exhaust.

 

Also check the fan clutch hub.
I'd say that's the most likely culprit.

 

Yup I'd say is that stupid fan. I'm actually having this problem with my T2 right now with the hot weather here in South Texas. My fan is not engaging right so Im looking for a Fiero E-fan (has always worked great for me).