Automotive Air Conditioning Information Forum (Archives)

woodardhsd on Tue May 13, 2014 10:47 AM

Year: 1999
Make: Dodge
Model: Ram
Engine Size: 5.9 Dsl
Refrigerant Type: r-134a
Country of Origin: United States

My 99 Ram with the Cummins diesel engine has been making squealing noises that I thought were due to a bad belt. After a new belt didn't fix the problem, I realized the compressor pulley bearing was noisy. I removed (after a struggle) the pulley and replaced the bearing with a new NSK bearing. The old bearing was slightly noisy, but would spin OK. Got it all put back together and the noise stopped. That was back in January. In the last few weeks, the pulley started squealing again. Again, I pulled it apart. This time, the bearing was all burnt up, and the clutch hub showed signs of heat (paint bubbling off). I showed my dad the bearing (he helped me replace the bearings) and he thinks that the compressor is probably on it's way out and made the bearing get hot. The shaft on the compressor still turns easy enough, no catching or grabbing. The compressor was still working fine all day during our 150 mile round trip in 90F weather.

One other thing I will mention: my compressor (sanden SD7H15 type, model no. U4750) had a splined clutch hub instead of a keyed one like the manual said it should. So I wasn't able to pull it off with the rental puller. I had to pry it off with screwdrivers like it shows in the manual here: http://www.omega-usa.com/client/images/SD_Service_Guide_Rev.2.pdf It was pretty rough when I got it off. After I replaced the pulley bearing, I put that hub back on if the off chance it would still work after straightening it up some. And it did. The compressor cycled on and off every 10 seconds or so so I hooked up my crappy recharging gauge to the low port. I could see the pressure drop down towards 25 where the compressor would stop. The pressure would climb back to 45 where it would start again. It was only around 70F outside.

So here's my questions:
1. Is it likely my compressor is just on the way out?
2. Did I cause a problem by using a potentially damaged clutch hub causing the bearing to overheat? If so, have I damaged the compressor?

zzyzzx on Tue May 13, 2014 11:11 AM

1. I think so.
2. Probably a moot point since I think your compressor is bad.

But then again, I am a bit biased since on the 2000 Dodge Dakota I maintain (also has Sanden compressor) , the compressor AND the compressor clutch locked up. I ended up removing the compressor and installing a shorter serpentine belt.

Edited: Tue May 13, 2014 at 11:11 AM by zzyzzx

woodardhsd on Wed May 14, 2014 7:52 PM

Is there a way to make absolutely sure the compressor is shot? I guess I could put another pulley and clutch on there, but by then I'm already halfway to a new compressor.

Assuming I need a new compressor, at a minimum, I have to replace the compressor itself, the accumulator, and the liquid line w/orifice tube, right? Looking at the store on this site, there are two compressors listed, one for $232 (20-04775) and one for $172 (20-04775-AM). I would assume the cheaper one is the reman, but they both say new. I went directly to Sanden's site and found a genuine sanden U4775-AFT compressor for just $250. I've never replaced a compressor before so I'm not sure about using genuine parts or aftermarket ones.

TRB on Wed May 14, 2014 9:07 PM

Tossing good money at a bad compressor is not a good option.

20-04785-AM

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When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com

Jag987 on Wed May 14, 2014 9:07 PM

the "AM" on the end of 20-04775-AM stands for "after Market". It will still be a new unit, but likely an import. Still a good compressor, but not necessarily of the same quality.

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I bought a can of 134a at w**-mart that had a stop leak, oil, and dye in it. It also had a hose and a gauge, so now I'm an AC pro!

TRB on Wed May 14, 2014 9:14 PM

I see as many failures with the OEM stuff as I do with the AM stuff. So I don't count the quality as subjective as I once did.

-------------------------

When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com

Jag987 on Wed May 14, 2014 10:09 PM

That is good to know.

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I bought a can of 134a at w**-mart that had a stop leak, oil, and dye in it. It also had a hose and a gauge, so now I'm an AC pro!

TRB on Wed May 14, 2014 11:25 PM

Quote
Originally posted by: Jag987
That is good to know.

Proper vendors do count in this area!


-------------------------
When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com

woodardhsd on Thu May 15, 2014 11:26 AM

Quote
Originally posted by: TRB
Tossing good money at a bad compressor is not a good option.



20-04785-AM

So you would recommend the AM version? BTW, I have the diesel engine so I think I need the 4775 instead of the 4785. The 4785 appears to be for the gas engines.

Just out of curiosity, what manufacturer makes these compressors? There wasn't a whole lot of info on the product page.

I think my plan now is to take it to the shop to be evacuated, and flushed. Take it home and replace the compressor, accumulator and liquid line. Bring it back for charging. Do I need to get the system checked for leaks before or after replacing the parts?

Thanks,
Mike

TRB on Thu May 15, 2014 12:10 PM

You are correct, the 20-04775-AM is the correct compressor for the diesel engine.

-------------------------

When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com

woodardhsd on Thu May 15, 2014 2:50 PM

Before I place my order, do I need any new o-rings when replacing the compressor, accumulator and liquid line? I don't see a kit available in the store. What about the PAG oil? Will my compressor come pre-filled?

As far as flushing goes, what do I need to look for in a local shop to do that for me? I have a feeling I won't find a HECAT equipped shop here in rural Eastern NC.

TRB on Thu May 15, 2014 4:33 PM

CP3014

Same procedure Hecat has suggested with whatever flushing product they have. Why not just order the flush 20008 when ordering the other items.

-------------------------

When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com

woodardhsd on Sun May 18, 2014 4:50 PM

I wanted to make sure I could get all the spring lock fittings disconnected before I ordered some parts. I got a disconnect tool set from AutoZone spring lock fitting tool from AutoZone I was able to get all the connections loose except for the one that connects the accumulator to the line from the evaporator. It's right up against the firewall, and up against the bottom of the cowling, so there's poor access.

Is there a trick to get stubborn connections loose? I didn't want to wrench on it too hard and cause a problem with the evaporator. This job is going to be expensive enough already without having to tear the dash apart.

Edited: Sun May 18, 2014 at 4:52 PM by woodardhsd

Jag987 on Sun May 18, 2014 7:47 PM

I know that fitting well. I did a recharge only for a customer last year on a truck about the same year. I couple of hours latter, I could hear it leaking. I went looking for the leak and that line blew off as soon as I touched it. With the limited space, I have found that sometimes a little, cheap disconnect tool like this works better.


Be careful and give it a good tug when putting to back together. This held fine under vacuum and appeared fine right after it was charged, but would have blown as soon as they drove off.

-------------------------
I bought a can of 134a at w**-mart that had a stop leak, oil, and dye in it. It also had a hose and a gauge, so now I'm an AC pro!

woodardhsd on Mon May 19, 2014 9:11 AM

I was considering that tool as well, but my local store didn't have that style. I'm pretty sure the tool I used got in there good and released the spring ( I could feel it release like it did on the others) but it wouldn't pop loose. Any thoughts on cutting the accumulator line before it connects with the evaporator line? Here's how the parts are layed out


Another thing I thought of while I was working yesterday. If I replace the parts myself, then take it to the shop for flush, vacuum, and charge, what do I do about the connections to the items that are going to stay and be flushed? The liquid line connects right to the condenser, and the accumulator connects right to the evaporator. Both of which need to be flushed. Plus I'm worried about uncapping the accumulator lines and letting moisture into the system.

Edited: Mon May 19, 2014 at 9:15 AM by woodardhsd

zzyzzx on Mon May 19, 2014 10:20 AM

I use these:
http://www.harborfreight.com/4-piece-a-c-fuel-line-disconnect-set-98118.html

zzyzzx on Mon May 19, 2014 10:21 AM

One I have released the spring, if it does not come right out, I turn the like back and forth until it does.

Dougflas on Mon May 19, 2014 3:16 PM

If the line won't come apart and you're ssure the spring is released, try heat from a heat gun or a good hair dryer. As long as you plan to flush it, try a solvent on the connection. You're correct, they can be a bear to separate.