Argh! I just got back from Arizona, in my (well maintained) 95 LX. The AC works great here in California in 90+ plus. But Phoenix last week was 111 degrees! I travel in the morning or evening when it is not so hot. While there, I needed to take a 60 mile (day) freeway trip. Here is the scenario.

Driving along with AC blowing cold, I look at the instrument cluster and see the Heat Gauge up above mid range, never seen that so high. Not boiling over, but running HOT, HOT, HOT. I slowed down and went over to the slow lane.

I started playing "yo - yo" with the AC switch; turn it off and the temp went down to normal. Needless to say I was burning up. So I turned it on and there goes the temp, up. Shut off AC, temp went down. What the heck?

Here in the California Central Valley it gets over 100 degrees, but Phoenix was "cooking". I had one person tell me: it is just too hot for some cars..." you got air conditioning and can't use it". Anyone ever had this?

 

I would inspect the cooling system especially the radiator and fans. On the radiator if it has the brass core looks for missing and detached fins at the bottom. Also look for the core to be caked with something on the condenser side either core material. The air is putting a higher demand on the cooling system coupled with the temperature.

 

Make sure that both fans turn on when the a/c is running.

Also make sure that the radiator is full of coolant by removing the cap and topping it off when the engine is COLD.

After inspecting the radiator, you may want to lightly spray water on the fins of the radiator and the a/c evaporator to clean any dirt and debris that would block air flow through those components.

 

Never heard that one yet ..a/c should cool in the low to the mid 40s ,,if it is Hot and humid it might be a few degrees higher

if engine is running hot , it will affect how the a/c cools ( not as cold ),,make sure that both fans work and that system is set on REC and not on FRESH

 

never had my car in az but i have been down south on 100+F days and never had a problem with A/C

 

I never had this before. Everything is clean, fans work. I wondered if the original compressor might be laboring, I can feel the car slow down a little when it comes on. Thanks for the input...I'm back from my trip (Ca.) so don't have to worry too much.

 

I think there's a pressure-interlock switch to prevent the compressor from engaging when the refrigerant pressure is too low OR TOO HIGH.

Is it possible the system is over-charged? It'll have higher pressures when it's really hot outside.

 

Do you have a an Aluminum or Copper core Radiator?

 

Higher pressures...you know I have a full set of gauges, but when I installed the Artic-Freeze, I used the gauge on the can. Maybe I should go check.

Got a brand new radiator in 2006. How would I know Copper or Aluminum. I'll check that out. Thanks for the input.

By the way: My Refrigeration mechanic buddy in AZ, says to use ES 12a, from Autorefrigerants.com. He tells it "beats the hell out of ALL other Freon". Can be used in an R-12 or 134a system, compatible with all oils. I think I might try it. I should post this...

 

Check your antifreeze to water ratio in the radiator. I had this same problem recently with my 97 after having the timing belt/water pump replaced. I drained out some of the antifreeze from the radiator and replaced it with straight water and the problem went away. For some reason if you have too much antifreeze and not enough water, it will not cool correctly. I had the same problem years ago with a 1980 Datsun 210. Hope this helps if you haven't already fixed the problem.