I bought a 5 speed 92 Mazda Protege with 189k miles.

When I leave work, I'm driving 55-60 mph for maybe 10 minutes until I hit the 35-45 mph zone.

I can stop at a stop light and no problems. I notice RPM is between 1100 and 1200.

When I get through, I get on the highway @ 55 mph for about 5 minutes.

then I drive in a 30-35 mph zone for maybe 5 minutes until I reach a store near my place or Hardees drive-thru.

Thats when my RPM is going up to as much as constant 2000 rpm instead of the normal 900. Temp gage goes up. If i stay still it will keep going up. If i move at least 15 - 20 mph it will go back down. I get heat in the morning and on my way home. I am not sure if i get heat when its overheating because i usually turn it off because it gets warm inside easily.

 

Time for a cooling system service & a check to see if the cooling fan works & a test of the coolant sensor/sensors.