Air Conditioner Compressor

Weave

Veteran Expediter
Charter Member
Well, low and behold I went to use my A/C this week and it didn't work, even after I carfully cycled it a few times this past winter to keep things fresh. The system refrigerant level was low, and I recharged it to the proper level, and it worked for about an hour, and died again. Took it to an A/C shop in town, and the system was fully tested, and it was found to be a blown compressor. This is the first truck I have had with the Sanden rotary type compressor, and the A/C has only been used two summers. I bought a new compressor ($200) and a new dryer ($22). Of course one of the fitting nuts on the comp had to be siezed, which damaged it, and the line had to be replaced too. ($95). Question- am I going to have to go through this every two years with these Sanden compressors? The reciprocating comp on my old FL70 lasted the life of the truck and was still working when I traded it. Just wondering if these rotary jobs suck or I just had a bum one- I hope it's the latter, because this stuff was sure expensive, and I did the labor myself, if I didn't I'd be into well over $500 for some A/C.
 

streetsweeper

Expert Expediter
Oh Weave....You had fun, huh? Without physically looking at your A/C compressor I'll take some shots at what may have caused the Sanden to fail.

1-lack of/or improper refrigerant oil. Might have lost crankshaft seal, usually indicated by a big oil stain behind the clutch asy & spread all over the front bearing housing plate.

Proper refrigerant oil used in automtive A/C R134a systems should be PAG or POE68. Or the oil specified by the manufacturer. The ones I use in the small truck refrigeration unit Sanden 508 & 510's. Their the same ones used in diesel truck app's too.

2-use of wrong refrigerant. Was it converted to something other than R134a in the past? I've seen guys use R409 in them & trashed them out. I've had to break the systems open after a failure & completely flush each part of the system, condensor, evaporator, all lines and replace acummulators.

The longevity of Sanden compressors- Sanden makes them damn near bullet proof. If the A/C mechanic don't take the time to perform a proper system cleanup you will experience another compressor failure.

Sanden is real tough about warranties. I fought them tooth & nail on several failures that came through the shop. Any kind of leak, oil or refrigerant that's ignored, or a bad repair job by the mechanic, they will not warranty & make no bones about it.

Everybody's refrigeration units up to snuff? Warm weather is a coming!
 

Weave

Veteran Expediter
Charter Member
The guy who is working on it now seems to agree with the low refrigerant level theory. I probably ran it last year for too long without enough- now I have to pay the price. I was using the proper 134A, I just recharged too little too late. He is going to flush out and inspect everything else on the system once the new line I had to order from Freightliner comes in and he gets things back together. I'm never going to neglect it again for sure. Thanks!
-Weave-
 

Weave

Veteran Expediter
Charter Member
Note for Freightliner Century/Columia owners:
A/C serviceman found source of my refrigerant leak that killed the compressor. There is a junction under the sleeper where the heater and A/C lines go into the sleeper climate control box from the junction under the hood. It seems one of the .59 cent hose clamps on one of the heater lines was touching one of the A/C lines, and rubbed a pinhole leak into it. The refrigerant was being lost as a gas, so the leak was virtually invisible, short of a little black residue. Might want to check for this possible headache on your Century or Columbia.
-Weave-
 

streetsweeper

Expert Expediter
Howdy Weave & Gang!
I've been out of things for a while. Been doing job interviews around the country. Glad your mech got the leak found. That black residue is your refrigeration oil.

make sure he does a thorough system clean up, preferably a 24 hour evacuation procedure. After that , your A/C should be most excellent even in the warmest of weather.

Take care!
 

davekc

Senior Moderator
Staff member
Fleet Owner
like I put in a earlier post. If it is a frieghtliner with a cummins engine, plan on numerous a/c repairs. Had a previous freightliner with this set up and it was a piece of junk. Went to a Kenworth with a cat and haven't had one problem. It is a 99, 300.
 

Weave

Veteran Expediter
Charter Member
The A/C repair we are working on now is a '01 Freightliner Columbia with a DDC S60. I was given the pleasure of doing the repair work myself, and the A/C guy showing me the ropes and supervising. It is now being "evacuated", hooked up to a vacuum pump to remove all the old oil and moisture from the system. It will be pumped up with nitrogen in the morning to check for leaks (or any repairs I did wrong in other words). Then I get to fill it up with R134 and oil if I did my job right, and watch the high and low end gauges for the proper fill level and performance of the compressor and fan cycling. This has been a fun project for me! The one line I replaced to the sleeper was about six feet long with no second chances.
-Weave-
 

davekc

Senior Moderator
Staff member
Fleet Owner
for what ever it is worth, the cummins a/c problems were tied to excessive vibration that developed over several months. Problems were seperate but numerous. Everything from cracked brackets, belt and pulley alignment issues to several compressor replacements. The one we had could have been helped by using a serpentine belt system, and auto belt tensioners, different bracket assembly and different compressor. Had control and valve issues but those were frieghtliner problems. They did come out with a new bracket and it went 6 months instead of two.
 

Weave

Veteran Expediter
Charter Member
I agree the A/C system on my old Cummins B 5.9 seemed to be a product of afterthought engineering. The trick to making that bracket last was you had to REALLY beef down the lower pivot bolt to make sure the compressor couldn't vibrate. The cheesy little single vee-belt drive was good for 2 or 3 belt replacements every summer, and with the factory size belt, was a real pain to slip over the pulley even with the compressor backed all the way off. I remember just about sweating to death one afternoon cussing like a trucker trying to get one on in a truckstop parking lot.
The DDC A/C project went well, it now cools the cab to about 45 degrees in a matter of 15 minutes. The DDC compressor mounts solidly to the engine with four bolts, and is driven by a little surpentine that can be replaced in about a minute or two. It is the best setup I have seen so far for ease of maintenance, and Freightliner isn't usually noted for making things easy:+
-Weave-
 
Top