Freightliner Columbia A/C problem

You may want to rethink that one bud....
Mechanics are the guys that will tear a transmission apart, change a bearing, and reinstall it.
It's the "techs" that are parts swappers.....
Cannot remember any "technicians" being around 10-20 yrs ago myself, but I do know the "mechanics" that were around actually tore stuff apart and fixed it, instead of swapping parts over.

Martin

 

I have a 2002 Columbia and the a/c pump is blowing or purging oil from the safety valve before the pressure release kicks in, my question is what's causing this problem. I replaced the binary switch on high side but still no fixing the situation. Replaced aa/c pump

 

First problem. TA. Second problem. What is the "main bolt" and I was not aware of an A/C dryer fuse. If your compressor failed it is likely the system is contaminated w/metal. On a Columbia (blend-air especially) the compressor, both expansion valves (sleeper cab), dryer, and condensor must be replaced (the condensor is a parallel flow core and can't be flushed). The evaps and lines must be flushed when going back together. And for the tech/mechanic arguement. Both are useful at what they do, but I'd take a technician. True, you didn't see tech's 20 years ago, but find a 50 year old mechanic that can correctly diagnose a multiplexing problem on an M2 or Cascadia.

 

I'm having problems with my a/c. Replaced the compressor almost 2 years ago. Worked great last summer, and all of the sudden it seems to run then not cool. Then when the fan comes on or I'm high in the rpms it will get cool again. It still blows and everything, just stops blowing cool air. Real annoying. Fixing to get real hot here in Texas and I need my A/C working bad! Also, if I'm at idle and running the rear unit after a few minutes the air is still blowing, just warm. Really sucks.

 

Could be as simple as being low on freon (R-134a)

 

I'm do for another PM here in the next week or two, and I think I'm going to have them drain and refill the system and see if that helps. Hopefully if there are any leaks the dye will show.

 

A/c systems will gradually lose some over time but it doesn't hurt to service it every now and then. If there is a major leak the tech should spot it without too much trouble.

 

Where would the AC relay be located at

 

Okay where do I start. I've got a. 2004 Freightliner Century. I spent .$2400 doing the same thing your doing. every time you open up the lines on a air conditioner system you must replace the air dryer. If you don't the desiccant pack inside will explode and contaminate all the lines. You must remove both expansion valves and flush the entire system. Install two new expansion valves and a new air dryer. Take it to a shop and have them do a evac and recharge. They can also test the system for leaks by holding it under a vacuum. Also make sure they charge the system with a proper amount of freon. 3lbs 7ozs. 3.44lbs.