I've searched. I've read and I am just looking for suggestions.

Story
Summer weather temps have arrived and my AC problems returned. The AC works fine driving down the highway and it cools enough to the point I don't need to have it on high all the time. But once the outside temperature hits 90 deg + I start having problems in stop-n-go traffic. The compressor clutch will disengage, hot air starts coming out the vents and the engine temperature starts to rise until I shut off the AC button. But once I get back moving on the highway it will start cooling as if nothing is wrong.

Where should I start?

Thanks!

 

Cooling at speed, but not at a standstill is usually an airflow problem. The issue is that for some reason, at idle, air is not being drawn across the condenser in a way that properly transfers heat from it. As a result, the A/C becomes less efficient.

Usually, a cooling system issue is also a potential cause.

Do you have an electric or mechanical fan clutch? if mechanical, what is the state of the fan clutch? If you grab the fan (ENGINE OFF) and spin it, does it spin loosely, or is there resistance?

If you have electric fans, do they go instantly to HIGH when you turn the A/C on?

 

I'll have to check the fans. I know that I can stand there and have someone start the car. Compressor clutch engages. If the car is cold it'll take a while and the compressor clutch will disengage. If the cars hot and I start it the compressor clutch won't engage or will engage for a few seconds and then shut off. But once I hit the road everything is fine.

 

Have you ever had it recharged? If so you could have to much pressure in the ac unit which causes it to cut off after a few seconds and also causes it to work when it wants to on the highway. Same thing happened to me i had it recharged with the prper amount of pressure and it works fine. Try what that guy said first then try what im saying it has to be one of the two!

 

Interesting, I'm having similar issues...

 

I was actually referring to the fan clutch if you have a mechanical fan. Check it's condition.

If you have e fans, have someone turn the ac on and the electric fan should crank to high right away.

Second tp cooling issues would be a low ac refrigerant charge. For this i would recommend a professional instead of just blindly dumping cans into the system...unless you know what younare doing.

That's why I suggest checking airflow first.

 

OK now I can explain the fan setup. It's a mechanical fan for the motor and it has resistance. Then it has an electric fan two stage. It seemed to be working fine with the low stage on when the AC button is off and then goes to the high stage when the AC button is on. The temperatures cooled off enough now to where the AC would just stay working as it should all the time. Like I say once the temperature gets above 90 deg and in stop and go traffic you can hear the compressor clutch disengage and from what I can remember last year the electric fan would either shut off or go to low stage. I guess my first option is to take it in and get the charge checked?

 

My money is on the fan. An incorrect charge on the AC system wouldn't cause the engine temp to rise and you wouldn't have AC trouble only during stop & go driving.

 

Your right about the temp of the G but my car ac would work when it wants to I could hear tge ac engage then disengage so get that check just in case it could be both together.

 

Sounds like your fan clutch has failed.

There is no real way of checking it without risking your life a bit..


One less risky way is to do the following:


Roll a newspaper into a tight circle, turn on the car and with the hood open and car on slowly apply pressure using the newspaper on the fan. If you hear the fan slowing down and it STOPS while the engine is on... that fan clutch is damaged. If the news paper becomes powder or the fan does NOT slow down at all your problem could be trapped air in the system.


My best suggestion is to check the fan clutch then proceed to checking fluids, if the water is being pushed out of the reserve you may have already incurred engine damage.

 

So I took the car in yesterday to check the charge. The technician said the charge was fine so then we started looking at the operation of the electric fan. We turned on the AC button and the fan turned on. The pressure on the high side was increasing over 200. Then the fan went to high and the pressure stopped around 300 and wouldn't go down. Dirty condenser?

 

Are the fins all smashed up and full of bugs and such? You can try cleaning the fins, and using a tool to straighten them.

 

Fan clutch

 

Details. What am I looking for?

 

Here this is how you can prove my theory....

Grab an obd scanner. That allows to view live. data. View the temps if they over 198 while standing still you have a bad fan clutch. Fan clutch keeps the temps at less than .190.