I have an 03 F250 7.3litre. I have noticed the last few times driving while hauling that my vents start pushing hot air when under a load (example: driving up a long,steep pull) even if I have the AC on. It's starting make me a lot hot under the collar (pun intended)

Any advice?

 

Search for "A/C shim" on the forum and watch the video below. This is likely your problem.

 

ok. I'll check that out when weather clears. But yesterday going to Denver I was just running the vent and while climbing with my trailer it started blowing hot. Then of course once the hard pull was over the vents started blowing cool again. This did it with the AC on later in the day, but then AC cooled off once the hard pull was over. So I get the shim part but why is it doing it if I'm not even running the AC?

 

Don't quote me on this, but I believe that the A/C is always running, except when you have it on defrost on the windshield. I know the A/C is running most of the time, despite the temperature setting, but I cannot remember for sure which setting it is not running in.

 

IIRC ac compressor only runs in ac, max ac and defrost. Next time it happens reach up and see if air is being diverted to the defrost vents. This would indicate your losing vacuum and the blend doors are closing. Not sure how a hard run could cause it though.

 

How involved is that to address the blend doors. And my AC runs when I have it on the Vent/Floor setting too. Always has.

And the air still was blowing out the panel vents, wasn't being diverted

 

if it was still blowing from the vents then it is not a vacuum problem. waiting now for someone who has had a similar problem

 

I'm leaning towards the AC clutch issue like Sous pointed out, makes sense. While cold/cooler, clutch engages fine. When warmed up/hot the clutch has issues staying engaged.

Just my 2 cents,

Baatzy

 

Well, I gauged the gap. It's pretty wide. Certainly nowhere near the 0.02 that the video recommended. I'll fix that tomorrow night. Should help, I hope

 

Keep us posted. I had a very similar issue and removing a shim helped and eliminated the humid/hot air being put out through the vent. I ended up having refrigerant checked and topped off, but the real fix was the shim.

 

So the shim didn't fix the problem. AC blows a lot colder but when I start pulling up long, steep grades she starts to blow hot. I have to turn off the temp control and roll window down. Water temps are reading fine, not throwing any codes. Soft or hard.

I'm at a loss.

 

Well, it could be the refrigerant is low. I had mine checked just to be sure the system was in top shape even after adjusting the shim space.

 

Is that something I can do by buying a refill kit at the parts store? Not too many trustworthy shops here and the people they hire are only here in this area to make enough cash to buy and smoke pot. Isn't Colorado swell?

 

You can try it, but I usually leave it to the professionals and pay a bit more for the service with the proper gauges and devices to get the job done right. Although, I have a very reliable shop to take my vehicles to that I trust.

 

Hummm...I think I suggested to check your freon in the other thread. The air gap check is for if you have consent warn or hot air. Since you have cold and hot you have a different problem.
Yes you can fill your freon yourself. Get the AC Pro at any parts store. Very easy to do with great instructions. I did mine last year and works great.