A/C and ventilation
 

Hope this is the correct forum.
I'm still new to my 2000 F-350 PowerStroke. A few weeks ago we hooked up the trailer for a trip to the Grand Canyon.With ambient temperatures in the mid 70's there was not a lot of need for A/C but I noticed that when we did try to use it when the truck was under load, there was quite a noisy cycling of the A/C compressor. It didn't sound destructive just noisy and while cycling it became useless in providing any cool air. Is this normal?
Then when I decided to turn the A/C off to relieve engine stress and tun the vent on, it felt that the vent air was the full engine bay temp. Does the vent not draw from a fresh air source?
Thanks, Rich

The noise you heard while towing and running ac was probably the radiator cooling fan. You can stop hot air from vent by cutting off coolant flow through heater core. Install a ball valve in either heater hose so that coolant flow can be turned off during summer. That will also make ac blow colder.

You may have a couple of different issues going on here, I will try to keep this short and informative.

Verify your compressor clutch is operating properly, if not follow the video below.


Your evaporator coil may be clogged up and not circulating air as it is designed to. Check out the video below.


You could have a bad or corroded resistor. Check out the video below.


Your fan (squirrel cage) could be damaged or not operating properly. There are 3 screws holding it in, simple to remove and check out function.

You may want to think about installing the Ranger/Excursion valve or manual ball valves to shut off the flow of coolant to the heater core.

Have you checked/cleaned the condenser coil in the front of the vehicle?

Wow! Thank you so much for the good suggestions and videos. I am assuming that a brass ball valve would be the best?
What made me think that the noise was the A/C compressor was that as soon as I switched the A/C off the noise would stop. Would that cooling fan do that as well?

Thanks again, Rich

It depends because one persons best method is not another persons. I prefer to have the heater core with coolant flowing through it and then the vacuum valve shut it off when I switch the knob to Max A/C. Others prefer to have the ball valve shut during the summer and open during the winter. Like some people prefer ESOF the way it was designed and others prefer manual locking hubs. It is up to you.

The cooling/radiator fan cycles on and off based on temperature. Sometimes my fan will kick on for a few seconds as I am starting in low or 1st gear when towing heavy. Then by the time I am doing 20 MPH it will shut back off. It sounds like a hovercraft is under the hood when the fan is going full speed.

Thanks Sous! Yep, definitely a hovercraft under the hood when it hits.