I've got a 2000 F350 PSD XLT. When I turn on the AC it runs and cools fine. However, the first time the clutch cycles off or you select another position then back to an AC position the clutch will not reengage. The high and low pressure check good. Any ideas on how to trouble shoot this. Thanks.

 

I had similiar problem and replaced the sensor switch that engages the clutch.

About $25 from the local dealer.

 

av8orhd,

It is sooooooo nice when someone accurately describes the symptoms, as you have done here.

You have a classic case of the air gap in your compressor having worn too wide.

Try this to test:

Turn on the A/C and run it until the clutch won't re-engage. Be REAL CAREFUL now! Take a plastic screwdriver handle and "tap" the end of the (not spinning) clutch. Does it immediately engage and operate normally until it next cycles off, and then won't re-engage on its own?

If so:

Get out your feeler gauges, or your calibrated eyeballs, and determine that the air gap is about .050" to .060" (fifty or sixty thousandths). That's too much! It's supposed to be around .030. But wait! There's no need to replace the compressor and have to re-charge the system. There's a "dirt-cheap" fix!

See the little bolt right in the middle of the compressor shaft? Take it out. You won't be letting any Freon out. Pull the clutch plate straight out. There is one or more "shims" that look like small washers in there, either on the end of the shaft or down in the hole that fits on the shaft. Take off about .030" worth of them and reassemble. Go ahead, use a little blue (NOT green!) Loctite on the bolt as insurance.

Make sure you now have at least .025" of gap. Start the engine and check to insure your problem is gone.

That's all there is to it.

Pop

 

when you guys talk about the clutch are you talking about the ac clutch? where is that in the engine. my truck is starting to do this and in pheonix thats not good.

 

This worked to fix my AC problem THANKS!

A couple of things to help:


Take a plastic screwdriver handle and "tap" the end of the (not spinning) clutch. Does it immediately engage and operate normally until it next cycles off, and then won't re-engage on its own?

This can be done with the engine off and the key turned to "on". The clutch will engage but it won't be spinning. Also, when you do this test with the engine not running and the clutch is engaged, it will hold the clutch in place so you can loosen the bolt. Just remember to turn the key to off/lock before starting repair.

Good Luck!

 

zstyle01, as per your post above, i would suggest that you not touch your truck and drive it to a mechanic. sorry.....lol.

 

I have a 99 Ranger 3.0. My A/C would blow cold for 5 minutes or so then the compressor clutch will cut out.
Compressor will remain engaged all day sitting at idle, but when I raise the rpm's abit the clutch will drop out within 10-15 seconds. And will not re-engage. Before I realized this much, I had a shop check it and they told me I had a leaking evaporator. I was skeptical but I replaced the evap and orifice, and had the same problem.

I got to looking on the web and found SpringerPop's info here and I looked at my clutch plate to find about a .070 gap.
Pulled the plate as per Spring's instructions and found one shim/washer. Removed it reassembled, now the gap is about .025. Gave it a good test run and so far it's all good. The compressor still cycles occasionally with the rpm's above idle but now the clutch re-engages by itself within 2-3 seconds.
So bottom line I guess is this. I don't know until I get some gauges on it if I have a pressure problem??
Anyone have any idea about how often a healthy system will cycle say at a normal driving rpm??
I realize there are a hundrfed variables involved temp, humidity etc etc but I'm just trying to get an idea. ie; would it cycle like every 30 seconds or 30 minutes, or even less???

Anyway I'm chilling again and I hope all is ok, and I want to thank SpringerPop for the great info.
Dennis,
Providenciales, Turks and Caicos.
ps: my A/C runs 365 days a year...

 

this sounds just like the problem i have I'll be all over this tomorrow night

 

DITTO - I'm going to try to do this tonight after work!! Thanks FTE!!

 

Not to derail, but thanks. I've been having an ac issue, not exactly same as above; mine just stopped working - clutch stopped engaging. I overrode the low pressure switch and still no luck.

Anyway, I measured the gap - .049" , bad, just did your screwdriver trick and clutch engaged. Now its cycling on and off about once a second - 1 second on/one second off (AC set to max). I'll rework the gap as you described. Hopefully that does it. Thanks again.

 

Visit the forum section that specializes in HVAC problems and see the FAQs posted there.... Many of your questions are already answered there.

 

Springer is on to something that even a google search will not answer for you...hehehe. My 99 SD 250 has been doing this since it's inception and nobody seems to have a clue what's going on. I was told that I was @ a 1/2 pound low on freon was the most recent. From what I've read on this thread, alot of people have been gouged by some crazy shady mechanics out here just looking to make a buck, well, not my big butt. I'm fixing my damn A/C tomorrow first thing. Last week it was high 90's to triple digits here in Hot *** Alabama...hehehe...gonna' be nice to have icicles hanging off my ears on friday....hahahahahahaha. thanks so much Springer.

 

Just be sure to not take ALL the spacer shims out (unless it's necessary), as the clutch MUST have some air gap.

It HAS to be able to cycle on and off.

If it has NO air gap, it won't cycle off, and WILL damage the compressor by over-pressurizing the high side.

Pop

 

Will do Springer, very nice info.

 

Bump. Great Info. I will be doing this in oct when i return from Afghanistan. hopefully it works for my truck