I am the recent owner of an 01 2500 4x4 ctd. The AC worked for couple weeks and I kept hearing this sound like the ac clutch was wigging out. I finally layed under the front of the truck and found that it was the 134 busting out of the pop off valve on back of the compressor. I figured I would start with the line that holds the orifice tube. After I swapped the line we hooked up to the lines and started to put 134 back in after we pulled a vacuum of maybe 26 lbs. We started the truck after the first can went in to see what we had but it wasn't cold air yet. So we started to put the second can in and the high side pressure is getting past 350 by the time we are about 1/3 into the second can. We didn't get cold air until we got near 450 on the high side and near 35 on the low side. Needless to say we let some pressure out to just under 400 and I don't have cold air, maybe 70* air on a 75* day outside.
Any advice on what to look for next would be greatly appreciated. Is something under the dash plugged up causing the high pressure. I'm no ase certified mechanic but I can hold my own. I just hate to take it somewhere to let someone else work on my stuff.

Thanks

 

Two questions:
1 Was the old orifice tube/line actually plugged? I,e. Did you try blowing thru it with compressed air? If there was some detritus inside, some more of it may have plugged the new one too. Could mean the bag of dessicant has broken loose and has spilled it's guts...Not good!

No?
Yikes! 400psi and still going higher could mean there is likely insufficient cooling air blowing across the condenser.
2 What was the fan doing... I have a '97 so I dont know if the fan on an '01 is electronically controlled on this model yet like the newest ones are, or if is still the old style silicone thermo-clutch.. The clutch may have "bit the big one" and is just barely spinning the fan when disengaged and never gets above that pokey speed even when it should engage..
Point that baby into a strong wind and see if you get any cooling. Even if you have to set up a powerful shop fan to blow across it in the driveway and try again.
Some guys with the breather bottle have reported it belching oil onto the backside of the radiator and with the road dirt, forming a plugged radiator... No air for the A/C either.
Try a garden hose to wet down the condenser coils which should drop that pressure Right NOW. If that works well, find out why you don't have enough airflow...

Good luck...
K.

 

Your high side is high enough to consider a plugged orifice, but your low side is not low enough, so I also think your coils aren't being cooled by the fan, or are really plugged.

 

I checked the fan clutch and I think it is shot. It spins really free and isn't moving very fast at idle. I should have noticed that but I guess I focus on the task at hand to much. I will replace the clutch and see what that does.
I will also check the old line when I get home tonight.

Thanks a bunch guys, I really appreciate it.

Frank

 

Don't jump the gun on the clutch too soon. Those clutches freewheel VERY well until they get up to the engagement temp. Does it spin up the fan briefly upon a cold startup?
My clutch freewheels like crazy and I don't have any A/C cooling problems, but my radiator,intercooler, and condenser are clean too. I've only heard my clutch engage once while hot.. I had cardboard completely covering my radiator and it got up there in temp before that thing ever engaged.
While you have your head under the hood, check the backside of the radiator really well... Use a good bright light... Lots of dirt and the ever present oil splatter from that durn'ed crankcase breather bottle can REALLY plug up that radiator. Do a search and see what others have had to do to clean that radiator and some have moved that bottle from it's location.

K.

 

I agree - I wouldn't replace the fan clutch until you KNOW it's bad!

 

I'll check that also. Thanks a bunch.

Frank

 

Ok guys, I tried to blow through the old ac line and I could but it was like trying to blow through one of those little bitty straws that you stir coffee or hot chocolate with. I'm not sure how free it should be. The fan clutch was really free. You could spin it with your finger and it would keep turning several turns.
I put the new clutch on and my pressures were low (20 then climb to 40 on low side and just under 100 on the high side). So I added a can slowly and got it up to 180 on high side, then added most of another can to get the pressures to a solid 38 on low side and 250 on high side. I now have a cold air conditioner again! I personally think I had 2 problems but may never know. I am just happy to have it fixed.

Thanks to all who sent me in the right direction. It is much appreciated.

Frank

 

Good deal Frank... Glad you got it nailed.
Yes, the tube ought to be like trying to blow through (based on what GM brand A/C orifice tubes look like) about a 1/16" ID brass tube about an inch or so long.. I'll be honest, I've never actually seen the Dodge tube since it is made into the durned liquid line. But based on the similarly sized compressors, it ought to be essentially the same size.
CCOT (Cycling Clutch, Orifice Tube)style mobile A/C's are about the absolute simplest ever devised.

I guess your clutch was REALLY freewheeling! After you got it out, could you see any signs of silicone oil leakage at the seal?
With the engine idling, I know I can stop my fan by using a piece of rubber hose and then easily hold it from spinning with one finger. There is just a small amount residual torque from the silicone clutch even when disengaged. When I let it go, it will quickly accelerate up to several rev's per second. Even then, if I stop the warmed engine, I can push the fan hard and it will just barely make a full round. (about like the "Wheel of Fortune" )
They are pretty hard to get to engage since our radiators are so big. But when that sucker DOES engage, you'll surely know it as it will sound like your truck is trying to "take off" when the engine rpm's are up!
A piece of cardboard between the rad and the int'cooler will definitely heat it up...

Glad you're "cool" now... Just in time for the coming winter

K.

 

It's hard to say if there was any leakage because I don't know if it is from the clutch or the oil catch can that I haven't moved yet. It was pretty shot because it took a long time for it to pick up speed with the engine idleing.
The radiator must be pretty clean because the truck never climbed over 210 since I've owned it even with the clutch shot.