I have a 90 Accord EX with 250K miles on it. The past couple of days I have noticed that while sitting at long stop lights my temp will start to rise. This morning it got about half way up to the hot. Which is about twice my normal operating tempature. What is it that is causing this?? Any help would be greatly appreciated.

 

If you've had reason to open the cooling system (for any reason) you may have developed a bubble or "Void" area.
What happens is that this 'bubble' forms close to the water pump and at idle doesn't allow the pump to ...... pump. It isn't designed to pump air.

If it returns to the correct cooling range while moving, you could have a problem with one or both of the cooling fans mounted to the radiator. If these aren't working, you would have no air circulation thru the radiator while sitting in traffic.
Can you hear them running when you shut off the engine/

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It does return to normal operating tempatures when I am driving. And come to think of it I have no theard my fan kick on. I went and checked the fuse and it appears to be good. Not sure how to test the relay? Any way to test if the fan is working or not?

 

I've over the years cobbled jumper leads of different lengths. I use these to test components for viability.

I'd take several test leads, go directly to the fan motor(s) with one end connected to the + battery terminal. With the other supply a ground.
If the fan starts working, the motor(s) are ok.

At this point you can look at either the relay or the thermal switch which controls the system.

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Thank you very much for your help! I am going to test the fan motor and see how that goes! Thanks again!