I just changed my head gasket and I replaced the water pump and timing belt at that time. Now I'm noticing that the temp gauge is climbing to the top when the a/c is on. It did not do that before the head gasket was changed. It has plenty of coolant. I'm thinking of changing out the thermostat, but I'm not so sure that's the problem. Anyone have any other ideas? Thanks.

 

Hmm, how is the car's performance with the a/c off? Does it get hot when the a/c isn't on? Maybe the timing belt is off a tooth, that would probably make the engine heat up abnormally under load.

 

It cools back down to normal running temp when I turn off the a/c.

 

Check if the fan turns on when you turn A/C. Maybe it got disconnected in the overhaul process. Thermostat should not be an issue since the car cools down with A/C off. To test the thermostat just remove it and submerge it in boiling water and see if it opens properly rather than spend $35+ an unnecessary trip to the auto part.

 

The fan definitely comes on. When I got home the other day after it started heating up, I noticed both fans on when I opened the hood. Could it be something to do with my compressor? If the belt was too tight, could it cause a problem like this? The only reason I say that is because i had a loud squealing belt that I thought was the a/c belt so I kept tightening it. It ended up being the alternator belt.

 

did you bleed the air out of the coolant system afterwards? sounds like maybe you've got some air in the system...

 

Actually I did not bleed the cooling system. I'll give that a try. I don't know how that would affect the engine's temp only when the a/c is on, but I hope that's it.

 

If air pocket gets trapped in the system it will reduce your cooling capacity thus when A/C is on you are adding load to the system. Did you do the thermostat check I told you?. As for the belt being too tight all it may do is hurt the compressor's bearing in the long run but has nothing to do with overheating. Bleed system and check thermostat and let me know before taking it to the next level.

 

I haven't had a chance to do those things yet. I'll bleed it and check the thermostat this weekend. Thanks.

 

Air in the cooling systems on these Honda's does some strange things. Mine never overheated until I traveled 400 miles & was in Downtown Las Vegas in August & it decided to start overheating. It turned out that some shop did a hose for my mom & didn't bleed the the system.