Guys,

I am trying to solve this problem that doesn't make sense.
First of I would like to thank this web-site for fixing my COP and sparkplug issue, I fixed it myself on a Sunday afternoon and my truck has never run better....hats off to everyone here!!


I have a 2001 F-150 Supercrew, 4x4, Lariat, 5.4L, with auto transmission.
Been a great truck with supercold A/C since I bought in 2003, now have 185,000miles on it and just recently expereinced some weird problems with the A/C.
When you first start the truck and turn on the A/C it will blow cold as hell for 10-15-20 minutes......and gradually it will stop blowing cold air (usually it will convert to a vent temperature in about 30 seconds whent the A/C stops). It actually feels like someone just reached up and turned of the A/C.

If I turn the system "off" and continue on my way....within 10-15minutes the A/C will work again, sometimes for an extended period sometimes just for another 5-10 minutes before it turns off again. Just like someone is turning the A/C and switching to vent.
It doesn't seem to make a difference if it is on A/C or Max A/C.
Speed or rpm doesn't seem to make a difference, the truck engine termperature is fine.

I've checked under the hood and can't find any frost build-up, and you can tell the A/C clutch is not engaging when the weird "off" mood takes over. But the A/C clutch does engage when it first starts up for 10-15 minutes.

My guess would be a shut off switch or electrical connection that is turning it off, is there a relay that could go bad?

It just started doing this about a week ago and sometimes it will run for 15 minutes other times it will work for an hour or more. Really weird, I don't want to add coolant (134a) it shouldn't need it, it is cold as hell when working.

I checked some of the "pinned" topics and some of the other threads and didn't see anything that described my exact problem...so I thought I would inquire for some assistance......any help would be appreciated.


Oh yeah, my F-150 has been the best truck I have ever own!!

 

The first suspects to come to mind are the clutch gap and the cycling switch.

When the AC stops cooling, tap the face of the compressor clutch with a screwdriver handle. If the clutch engages, the gap is too wide.

If the clutch does not engage, suspect the cycling switch on the accumulator.

 

Figures- I let the truck sit and run for 20 minutes (wasting $4gas) and nothing, the A/C worked just fine.....so I jumped in and left, 10 minutes down the road the A/C stopped working. I turned it to "Panel" which is just a vent for 10 minutes and bingo the A/C started working again and stayed on the whole time!!
I did pickup a cycling switch on the way home at the auto parts store, cheap and easy....the hard part is getting to it. I finally found where it is installed on top of the accumulator but it has that huge electrical connection/seloniod mounted right on top of it.
Can the cycling switch be replaced without removing the seloniod bracket?
If that doesn't fix the problem and its the gap on the A/C clutch - what is the recourse/repair/fix for that problem? (new pump?)


thanks!

Drove in all the way to work today with the A/C on....it worked perfectly for 45minutes (go figure).

 

I'd skip the switch and go straight to the clutch gap.

Probably time for a "shimectomy"

Check the FAQs pinned to the top for more info on how to check it.

If the gap is okay, then you've got a thermal intermittent that is occurring when a component heats up.

Steve

 

well, I replaced the cycling swich this weekend.
Only took a few minutes and was $11 from local auto parts supplier.....might as well try the check stuff first.
It sat in the driveway and ran for 10minutes with A/C working the whole time.

We'll try it again this afternoon on the way from work, that's usually when it fails, when it is really hot and/or humid!!

 

well the cycling switch didn't make much of a difference.
I did tap it with a screw driver and viola' it worked!!

I removed the skid plate from my truck to access the A/C clutch and removed the clutch, I didn't find any shims just one tiny washer that fell off when I removed the clutch, I cleaned and re-assembled without using the little washer and it has worked ever since. There was alot of rust and durt buildup behind the clutch, I couldn't believe how dirty it was.

 

That tiny little washer WAS the shim.

You should be good for thousands more miles now.

 

WOW!!

I was really suprised to see that the bolt that holds the clutch was a 5/16th's....I was afraid to snap it off while trying to remove it. It was rather difficult to hold the clutch from spinning and get the bolt loose.
That little tiny washer didn't appear to be a shim but I thought what the #ell I'll try removing it. I almost didn't even see it. When I removed the clutch the washer must have fallen off and it was sitting on the face of the A/C pump in the grooves. I noticed it when I was inspecting the A/C pump and beginning to remove the rust and dirt.

all in all it was a pretty easy fix.

A/C has worked great, the whole state of Michigan has dropped 8-10 degrees and the humidity has been low since I fixed it!!

 

Your compressor repair dropped the temperature in Michigan over 8 degrees! I guess your fix worked.....for the whole state!

 

Good to hear you got it fixed I had the same problem on the wifes Honda accord. Still might be a good idea to check the clutch gap someone correct me if I'm wrong but I believe on that model its .014-.036 if its too tight you might burn up your clutch. Cheers