1990 civic 1500 gets a little hot on steep grade

[Proletariate]

Hi all, I have a 1990 Civic 1500 fi (sorry if this vehicle description is off not really a Civic guy but working on it). The car runs great, except when I am on a very steep grade the temp gauge moves from the bottom third of the temp range to just above the middle. I changed the thermostat a little while back. Coolant levels are constant and good same for the oil (it's fresh oil). The gas gauge tends to to dip up and down depending on the grade as well. 4 gears. One last thing to note is if I turn the heater on the gauge needle drops.

Any advice would be greatly appreciated.

[Proletariate]

I tried burping it today and put on a new radiator cap. No problems so far... Anything else?

[civicpride]

the ect sensor on top of the thermostat could be bad and giving false readings which also makes your car run harder than it really needs to. I had same problem! it's only like 30 bucks and a easy fix!

[LMFAO]

So long as its not nearing the top of the temp gauge I wouldn't worry about it, plus it's going back down so it should be fine, also make sure your radiatior has a clear path and isn't blocked by your number plate, or crap haha

[James Matteu]

Your owners manual should describe an acceptable temp increase as a result of either driving up a steep grade or towing a heavy load. Just be mindful of the fact that either heats both motor and transmission fluid. You may need to use the more frequent service schedule based on severe driving conditions.