AC clutch cycles on 4 to 8 times then quits

[navyjoe]

I have a 2006 3500. several days ago we where on a trip the temp was 88 degrees, AC was working fine. We stoped for a Doctors appointment started up the truck, no AC. We are on the road so I have no gages. I stopped at Walmart and got a kit with a single gage. Like magic the AC started working, connected the gage and it read about 45psi. It ran ok for the next 6 hours until I stopped the engine to Fuel up. It would not come back on has not worked since.



I've looked at the clutch and it cycles on 3 to 7 or 8 times when you start the engine then quits trying until you turn it off then same deal all over.



It would seem logical that it is low on 134a, has not been touched for 8 years and has worked fine until now. But how do I know? Also how can you add freon unless the system is running?



Any Ideas??????

 

[BDaugherty]

Check the gap between the clutch plate and pulley. It's somewhat common that you need to take the nut off then remove the outer clutch plate in order to remove a shim from between the two. It will look like a small thin washer. Once the shim is removed, put the outer plate back on and use loc-tite on the nut. What I've seen is that once the coil warms up, it isn't strong enough to engage the clutch with the extra air gap. Removing the shim will adjust for that wear.

 

[navyjoe]

Check the gap between the clutch plate and pulley. It's somewhat common that you need to take the nut off then remove the outer clutch plate in order to remove a shim from between the two. It will look like a small thin washer. Once the shim is removed, put the outer plate back on and use loc-tite on the nut. What I've seen is that once the coil warms up, it isn't strong enough to engage the clutch with the extra air gap. Removing the shim will adjust for that wear.

That sounds reasonable! I can't get under the truck (its 2WD) w/o some equipment unless I remove the air dam. Is there one nut or 3? I see what appears to be three nuts when looking from above. Will I have to remove the belt to do this?

 

[Bob4x4]

Save your time replace the compressor,you probably have dtcs set in the tipm. Too many overcurrent events will kill the tipm.

 

[navyjoe]

Save your time replace the compressor,you probably have dtcs set in the tipm. Too many overcurrent events will kill the tipm.

I understand your point, but boy do I hate to open an AC system. Unless the person doing the work really knows what they are doing I could pay $1000 to have the compressor replaced just to have to do it again when I get home!

 

[B.G. Smith]

If you had 45# with the compressor running the charge is probably ok. Sounds like a control glitch. Does the blower continue to run when it stops cooling? bg

 

[navyjoe]

Yes, everything is normal except that the clutch on the compressor tries to engage then quits after several rapid attempts.

 

[BDaugherty]

there is one nut right in the center holding the clutch on. i've also bought complete replacement clutch assemblies off ebay for these trucks. once you get it up on ramps and get a better look, access isn't bad.

 

[navyjoe]

there is one nut right in the center holding the clutch on. i've also bought complete replacement clutch assemblies off ebay for these trucks. once you get it up on ramps and get a better look, access isn't bad.

BD,
Thanks for the info, I got crossed with another older thread and asked this question there so pardone me for asking it here too. Can I do all of this with the unit still bolted to the truck and the belt attached providing I get the special tool to hold the cluch while loosing the centernut?

 

[B.G. Smith]

It can be done in place if you can get the room to get the snap ring pliers/etc in there. The fan shroud will probably be the most in the way. bg PS I just went out and looked at mine, close quarters to be sure, looks like there might be enough room if the shroud can come out. bg

 

[Bob4x4]

Pulling the shroud is more work than the compressor

 

[navyjoe]

It can be done in place if you can get the room to get the snap ring pliers/etc in there. The fan shroud will probably be the most in the way. bg PS I just went out and looked at mine, close quarters to be sure, looks like there might be enough room if the shroud can come out. bg

Thanks twice!

 

[navyjoe]

Pulling the shroud is more work than the compressor

Good to know. Guess I would have to tie it up to releave strain on the hoses.

 

[Wingate]

I just attempted this on my 06 model. The clutch is a marginal design. Slide under the truck with a VOM, ohm the clutch coil wires. You should be able to find the specs online. I tried to replace just the clutch, but once I got it apart, found the front shaft seal on the compressor was leaking. Replaced the compressor, dryer, and expansion tube. Wasnt a bad job, took about 3 hours and 6 beers.

 

[navyjoe]

I just attempted this on my 06 model. The clutch is a marginal design. Slide under the truck with a VOM, ohm the clutch coil wires. You should be able to find the specs online. I tried to replace just the clutch, but once I got it apart, found the front shaft seal on the compressor was leaking. Replaced the compressor, dryer, and expansion tube. Wasnt a bad job, took about 3 hours and 6 beers. [/QUOTE

Thanks Wingate. You say marginal design? Do you feel it was not repairable, or would it have been Ok except for the leaking seal. Hoe many miles do you have on it?]

 

[Bob4x4]

The 06-07 compressors are not what I would call robust. I don't waste my time messing with them. even the replacement rebuilds do not impress me. Mopar has just released a new compressor we'll have to see how they hold up

 

[Wingate]

I just attempted this on my 06 model. The clutch is a marginal design. Slide under the truck with a VOM, ohm the clutch coil wires. You should be able to find the specs online. I tried to replace just the clutch, but once I got it apart, found the front shaft seal on the compressor was leaking. Replaced the compressor, dryer, and expansion tube. Wasnt a bad job, took about 3 hours and 6 beers. [/QUOTE



Thanks Wingate. You say marginal design? Do you feel it was not repairable, or would it have been Ok except for the leaking seal. Hoe many miles do you have on it?]

In hindsight, I am GLAD the clutch failed. Had the compressor failed, it would have been a MUCH higher repair due to the constant flushing, possible condenser and/or evaporator replacement due to metal fragments. Since it was just the clutch, I didnt have to worry about debris in the rest of the system. My truck is 7 years old and on its original compressor. $500. 00 got me a brand new compressor, dryer, oil, and expansion line. Changing the compressor was easier than laying under it trying to replace the clutch!.