overheats with ac on..

[Mar424]

I have a 94 Accord and the temperature starts to rise when the vehicle is stopped while the AC is on.

If i park at a stop light for more than about 30 seconds, the car will do like a little shake, the AC wont be cold and the temperature gauge will rise until i turn it off, or start driving again.

The radiator is new, and both of the fans do work when they're suppose to.
what should i check?


Also, I noticed that the overflow tank doesn't have a line to put the coolant back into the radiator. It seems as it comes out goes in the tank and stays there.... how does this work?

[jeffcoslacker]

The coolant tank siphons back and forth through the same line, works on expansion/contraction principle.

You say both fans work when they are supposed to...both should run constant with the A/C turned on, is this what's happening?

I suppose the shudder is probably the A/C compressor beginning to overheat and then shutting off as the high pressure switch cuts it.

It sure sounds like what happens when one or both fans don't run with A/C on....tell me for sure that they do, and I'll try to think of something else...

[Mar424]

I just made sure the fans work, and they do.

I started the car, with the AC off and the fans were off, turned the AC on and both fans came on.

[jeffcoslacker]

That's weird.

Nothing blocking the airflow through the front end from underneath I guess, right?

Has it been rejecting coolant back into the tank if you let it idle?

What was the reason for the radiator replacement?

Has it done this ever since or just started?

Does it heat up at all with the A/C off idling?

[Mar424]

Originally Posted by jeffcoslacker

That's weird.

Nothing blocking the airflow through the front end from underneath I guess, right?

Has it been rejecting coolant back into the tank if you let it idle?

What was the reason for the radiator replacement?

Has it done this ever since or just started?

Does it heat up at all with the A/C off idling?

Nothing is blocking it from underneath...and I dont believe it has been rejecting the coolant back into the tank...how do i check this?

I replaced the radiator because it had a leak and my car overheated..

I've only had the car about 4 months and its been doing it for the last 2, and a couple days ago it would heat up with the A/C off idling but i was just a little low on coolant then.

[jeffcoslacker]

Well I wondered if it's actually even overheating. They will push coolant over to the tank when they get hot, and start venting it out on the ground if the overheat continues.

This is a bit weird...goes against most standard problems. A thermostat that won't open fully will make them heat up at higher rpm, but run fine at idle and street speeds...one that's stuck closed will cause overheat regardless of speed. Like we discussed fans will cause your problem, but you are certain it's working right.

That only leaves a couple of things....but none involve the A/C in any way, other than just being a factor for quicker heating....

"A little low" shouldn't cause overheating. How much are we talking, and where did it go?

If you start the motor cold and grab the upper hose, check two things. Time how long it takes for the upper hose to begin to warm up, check the temp gauge periodically, and also note how quickly you begin to feel pressure in the hose. Specifically whether you feel pressure before heat, and if the temp starts getting too high before the hose gets warm...