A/C only cools while moving

[inspectorudy]

Just got back from a 600 mile round trip and the dash A/C only cools while moving. It starts to get warmer at red lights or while not moving. The electric fans seem to be running fine and the freon quantity reads in the normal to slightly high or advisory zone. Can you think of anything I can check before taking it in for the big bucks guys to look at it. It is an '05 Adventurer on a WH chassis.

[RocketDork]

I'm not sure that's abnormal. I know my coach does that too. The fresh air intake is near enough to the engine that it picks up the heat from the compartment and blows it on you.

Two solutions.

1. Keep moving!
2. Relocate the fresh air intake to a location that won't pick up the under hood hot air.

[Bill Adams]

I am not familiar with the setup so please excuse my ignorance. If the dash air has a Max setting, this would eliminate fresh air intake and only circulate the cabin air eliminating that possible problem.
Also, where is the A/C condenser located? Could it be somewhat clogged and the force of the air while driving is allowing cooling that the fans are not strong enough to provide?

[RocketDork]

You raise a good point. I don't believe I've ever run my dash AC on the max setting...

In that setting, I guess, yeah, if there isn't enough air moving to cool the condenser, then you may get warm air out of it.

Is it a change over what you are used to? If its changed, then it's likely that there's a problem.

["007"]

You may have a problem with Evans control valve not closing off the Hot water for heater. Some of us have placed a ball valve in water hose to Evans valve.
Read this post.

[bigskymt]

Besides the loss of airflow when sitting still you also have a loss of engine RPMs that move the freon.
You can try cleaning out the condensor for more air flow also.
If your heater hoses are hot as mentioned then your valve is leaking.
Max position will recycle inside cooler air through the evap. as opposed to warmer outside air.

[inspectorudy]

I indeed had to use the "Max" position for the whole trip. It helped some but I turned down the fan speed to medium only once and that occured during a rain storm and the outside temp dropped to 70 F. In regular A/C it never reached anywhere near a real cool temperature. I'll check the intake but on Max it should recycle the interior air only with no outside air being used. keep throwing more ideas at me please.

[TXiceman]

Check to be sure you do not have heat coming in trough the heater coil. Either the Evans valve or a damper door position. Also, have you run the engine up to high idle and checked the refrigerant charge and whether it cools. You should check the pressure at a high idle speed not idle.

You also need to check the compressor discharge pressure. Are you getting enough air over the condenser at idle vs. road speeds?

Ken

[inspectorudy]

Thanks iceman, I didn't have a set of gages only the pressure one that comes with a new bottle of freon. It was taken at idle and indicated above the green band (Good) and in the advisory band (Yellow) but out of the red band. I will chech the other items you mentioned.

[inspectorudy]

I have been trying to find my A/C fresh air intake in the front compartment and cannot find it. I found the big engine air intake but no luck on the other. I have an '05 Adventurer with the 8.1 in it. Any ideas?