OVER THE ROAD A/C COMPRESSOR

[JIM CHALOUPKA]

This is the second winter I have found A/C compressor oil on the floor of the parked bus. I am now convinced it requires a new seal on the compressor drive shaft.
This leak only occurs during winter storage. I am thinking that there may be an internal refrigerant leak past the compressor rings thus applying pressure to the crankcase oil of the compressor and forcing oil past the stiff from cold seal to the outside of the compressor.

Possibly all I need do is top off the oil and recharge the system and let it go until there is a constant oil leak.

There is not a clear view of the sight glass, so I can not accurately judge the oil level. This will require a professional opinion, I guess?

Adding oil to the compressor I believe will require the removal of the refrigerant prior to the process, but possibly not. The crankcase may not be under the same pressure as the head side??

I would also think an oil change for the compressor and a new refrigerant filter to be appropriate.

Has anyone had this work done in the past? What information/pointers can you give that would ensure a proper job, including, where to go for the work and were you a happy customer?

I do not wish to buy the air conditioning equipment to do this job myself.

I called a local charter coach line and the mgr. said he couldn't do the work at this point in time and to take it to W W Williams in Richfield, OH.

I have called W W Williams in Hubbard, OH (closer shop) and the service mgr said they would/could do the job, but he thought the compressor would have to be removed from the bus, something that I feel is unnecessary??
He would not give an estimate without seeing the bus.

Do you think I should just go to Prevost Nashville?


JIM:confused:

[Jon Wehrenberg]

First, if you have oil on the floor, it indicates several things. You are not driving the bus. To get oil to show up on the floor the bus has been sitting a long time. Also it strongly suggests you may not even have a charge in the system because oil leaks out a whole lot slower than freon, especially 134A. I cannot remember, but I'm not even sure comperssor oil sits as high as the seal level. The sight glass relative to the shaft will be the clue as to oil level.

Are you sure the oil is not from the oil reservoir?

The seal, if it in fact needs replacement, can be done right on the bus. The compressor does not even have to be removed. The clutch needs to come off (I think a 7/8-14 bolt) is used to press it off. The center of the clutch is threaded for that purpose. That exposes the flange securing the seal. If I am not mistaken the entire process is outlined in the Prevost servce manual not necessarily for you to do, but for the technician's edification. The seal is available from Carrier and can routinely be replaced in about 1.5 hours. I have photos of it being done on Jeff Raymond's coach.

As to changing compressor oil, unless the system has been contaminated I don't see the need, but as long as the compressor has been pumped down and the balance of the system isolated via the shutoff valves there is no problem draining and refilling the oil. After the seal replacement the technician will pull a vacuum on the compressor and add some refrigerant, open the valves and top off the system based on presssures.

If I were to look for someone to do this, apart from Carrier who managed to burn up my last coach I would seek out a commercial refrigeration company familiar with the Carrier compressors or a trailer refrigeration company such as Transkool(SP) because a lot of those refrigerated trailers use the same compressors.

I would also suggest you have the technician look at the compressor by removing the heads. Look at cyclinder condition such as scoring or broken valves. Scoring is a reason to replace the compressor, and if it is just broken valves but no cylinder wear or damage they are easily replaced with kits also available.

[tdelorme]

Jim, the first thing you say is that this is the second year you have found the oil. Well what did you do last year?? I will not believe you if you say Barb rode around the coiuntry last summer with no bus air, so don't go there. Whatever you did last time, do it again.
And as far as the guy telling you the compressor needs to be removed to replace the seal, do not let him near your bus.

[jack14r]

Jim,If the seal is bad you will see graphite material around the seal,it will be obvious black dust around the pulley of the compressor.

[JIM CHALOUPKA]

Ted,there's a post here somewhere about the same oil leak this time last year. I cleaned it up and never saw oil again until Jan 2010.
Last year I drove the bus and all was well and I want to keep it that way!
The air works fine, but I have lost about 1 cup of oil total over two seasons use, that I know of, and want to make things right before I have a big problem.
There is a large decal on the compressor that advocates checking the oil and using a special oil. It seems they expect the oil to diminish in volume during normal operation?

The sight glass has no line for level across it and is an even color, that of the oil all across the window. Seems like the oil level is above the glass? This is when the compressor is at rest. Perhaps the level will drop if it is running, but I think more likely to froth up? The sight glass can not be viewed straight on. This makes a good check difficult.

I have my large hammer and visegrips ready to stop any mechanic that tries to remove the compressor!:eek::D

JIM;)