1992 Chevy Lumina Temperature Gauge Rising

When I start my car gauge start rising slowly and at high speeds it goes down to normal but rises again at slower speeds and gets back to normal…

It sounds like it may be the radiator fan. Next time it is hot stop your car, turn the A/C off and check to see if there is a fan running.

Guess #2 would be the water pump. Has it ever been replaced? How many miles on the car now? Has the timing belt (assuming it does not have a timing chain)been replaced?

Other than the gauge is there any other indication of over heating? Have you checked the coolant level?

Thanks a lot! I have looked at the fan and it is working. Topped up the coolant. I will watch and go to the next steps in a couple of days, Car has 102,000 miles and I am the second owner for the last 2 years. I do not know the age of water pump or thermostat.

Has the coolant been flushed and filled in the last 2 years, or ever? If not, thats where Id start. If you can do it yourself, what Id do is get a bottle of Prestone Super Radiator Cleaner and follow the instructions.

Id also replace the thermostat if its more than a couple years old. Its cheap and easy to do. The thermostats on these cars dont seem to last very long, at least for me. Ive had a lot of GM V6s from this era.