90 Accord Ex
148,000 miles

Started up about a week ago the temp would rise pretty high (3/4 way up) on the temp guage. Sometimes it will go down if I turned on the heater and sometimes it will get hotter or cooler just on its own. When I shut off the vehicle the fan kicks in even on a cooler day or night.

I've noticed that it seems like only one fan might be working for the raditor ( the one right in front of the tranny)

What could be possible problems to cause this problem I am having?

Bad thermostat? Radiator? Coolant?

I'll probably just take it in this week but just curious if anyone might have had the same problem.

Thanks

 

Most likely its a bad thermostat...it just happened to me about 2 months ago.

 

Check your coolant levels, then your fans...turn on a/c to see that both turn on. If all is functional I would say thermostat especially since you are saying it goes down w/heater.

 

Both fans should come on at the same time. If only one fan comes on, it's probably bad.

Easiest way to tell if overheating is caused by the thermostat is to feel the radiator hoses. When the engine is at operating temperature, both hoses should be almost equally hot (actually the lower hose should be about 10-15 degrees cooler, but that difference is hard to tell at high temps). If the lower hose just feels warm, and the top one is hot, the thermostat is stuck closed.

 

Thanks for the great responses. I will check out some of the things you guys mentioned. Appreciate the help

 

The different hose temperatures is a way to tell if your thermostat is working correctly. When I had a bad thermostat, the lower hose was mildly warm and the upper hose was hotter than hell. Turned out to be a bad thermostat(brand new Stant thermostat). So, I bought myself a Honda OEM thermostat the temperature needle has been rock steady ever since. Just to be sure, go ahead and check your coolant level, relays, fuses, and coolant temperature switches.