1st Generation Dodge Cummins 89-93 Discussion of 12 Valve 5.9 Liter Dodge Cummins Diesels with Rotary Injection Pumps

A/C Compressor not pumping?

Old Jul 22, 2011 | 05:32 PM
  #1  
Edahall's Avatar
Thread Starter
|
Diesel Enthusiast
Joined: Dec 2009
Posts: 130
Likes: 0
Default A/C Compressor not pumping?

I decided to go ahead and replace my compressor with a rebuilt A/C compressor because the coil went out on the old one. It seems like the compressor is not pumping. The low side readings are maxed out and if I rev the engine to 2500 rpm, it'll bring the low side down to maybe 30 on the R134a scale (about 3/4 the way up the scale). It also won't take any more refrigerant yet I've only put in less than half of what I need. What's going on? Could it be that it's too hot outside? Or does it sound like a defective compressor.

Also, the compressor turns over just fine.

---AutoMerged DoublePost---

Also, the low pressure line is not getting cold. And yes, I did pull a vacuum before recharging.
 

Last edited by Edahall; Jul 22, 2011 at 05:36 PM. Reason: Automerged Doublepost
Reply
Old Jul 22, 2011 | 06:45 PM
  #2  
Only1*'s Avatar
Diesel Fan
Joined: May 2011
Posts: 32
Likes: 0
From: Kaufman,Texas
Default

It's not the heat causing the problem... If you want to check the compressor to make sure it's doing what it should,drop all the refrigerant from the system,start the engine and set a/c to cool,jumper the low pressure switch and watch your lowside gauge,it should go from zero to 10 to 15 inches of vacuum in under 30 seconds,if it won't pull at least 5 inches,it's a dud!
 
Reply
Old Jul 22, 2011 | 08:45 PM
  #3  
dcpowell17's Avatar
Diesel Fan
Joined: Jul 2011
Posts: 68
Likes: 5
From: Austell, Ga
Default

Only1* is right on! good luck.
 
Reply
Old Jul 23, 2011 | 05:49 PM
  #4  
Edahall's Avatar
Thread Starter
|
Diesel Enthusiast
Joined: Dec 2009
Posts: 130
Likes: 0
Default

Thanks, I will try that and report back.

---AutoMerged DoublePost---

Originally Posted by Only1*
It's not the heat causing the problem... If you want to check the compressor to make sure it's doing what it should,drop all the refrigerant from the system,start the engine and set a/c to cool,jumper the low pressure switch and watch your lowside gauge,it should go from zero to 10 to 15 inches of vacuum in under 30 seconds,if it won't pull at least 5 inches,it's a dud!
I followed your procedure and with the pump rotating, I didn't even notice a blip on the lowside gauge. It just stayed at 0.

---AutoMerged DoublePost---

Update: It's all working again. The verdict is the rebuilt pump was a dud. I ended up taking the coil and hub assembly off the rebuilt unit and put it on the old compressor. It blows very cold air now. The only problem left is the belt squeals real bad on the new hub assembly. If I spray some WD-40 on the hub, the squeal goes away. Is there any fix for this?
 

Last edited by Edahall; Jul 23, 2011 at 05:49 PM. Reason: Automerged Doublepost
Reply
Old Jul 24, 2011 | 10:14 AM
  #5  
Only1*'s Avatar
Diesel Fan
Joined: May 2011
Posts: 32
Likes: 0
From: Kaufman,Texas
Default

If it's not a new belt,it could be glazed causing it to squeal,or possibly the belt isn't tensioned well and it's slipping.
 
Reply
Old Jul 25, 2011 | 08:13 AM
  #6  
Edahall's Avatar
Thread Starter
|
Diesel Enthusiast
Joined: Dec 2009
Posts: 130
Likes: 0
Default

The squeal was almost as loud as a skill saw. However, I knew it was just the belt so I went ahead yesterday and drove 500 miles and by the time I got back, the squeal was gone.
 
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Maclain Marsh
Ford 83-94 6.9 and 7.3L General
3
Jul 13, 2015 06:23 PM
Jladanyi
Diesel In Distress - Support Ticket
0
Jul 4, 2015 02:43 PM
joldfield
6.7 Liter Dodge Cummins 07.5-12
0
Jun 22, 2015 04:27 PM
CumminsCoalRoller24/7
5.9 Liter CR Dodge Cummins 03-07
7
May 5, 2015 08:55 PM
JasonG.
Ford Powerstroke 08-10 6.4L
6
Feb 26, 2015 08:51 PM


Thread Tools
Search this Thread

All times are GMT -5. The time now is 03:22 PM.