I am having problems with my bunk AC. I have a 1998 Freightliner Century Class with Detroit Series 60. When I am moving my AC works properly. My thermometer reads 40 deg. F at the vent. After I sit for 5 min. or more the gauge reads 50 deg. F and the bunk vent is 70. I stopped at a garage and he added freon, but it was too much. It ended up blowing out the pressure release valve on the side of my condenser. Has anyone had similar problems with their bunk AC? Or AC over-all. If so, what are some solutions?

 

Put an inline valve in the heater hose to the bunk. The factory control valve often leaks and pumps heat into your bunk a/c all the time. Home Depot has a valve with 3/4" hose barbs on it for $7 that will probably fit - my FLD120 uses that size hose. You also need a couple hose clamps. You can clamp off the hose in two spots to cut a chunk out to fit the valve. Make sure the engine is cold and remove the pressure from the system by removing the radiator cap. I did a crappy job of clamping and lost about a quart of coolant - no big deal.

 

Pop the hood open too, just so it's not latched.

Turn on engine fan if you can.

 

Where is that factory control valve located? And once I find it, do I leave it in or remove it? Thanks for your help Roadranger.

 

In a FLD120 it is an electrically actuated, air operated valve located in the passenger side under-bunk compartment. It is controlled by the bunk temperature control so you probably want to keep it for the winter. I put the inline valve in one of the hoses coming through the floor of the sleeper, right under the floor where the bunk heater and a/c unit is - real easy to get to. By the way, in the FLD120 the regular valve is normally open - Mine was leaking air so I unplugged it and got an instant sauna! I have a slightly used bunk heater I'll put in ths winter so I may go ahead and remove the hoses entirely and plug the connections at the engine - but that requires draining the coolant and refilling. I've done that once to remove a couple of hoses that used to go to a now-rusted-out fuel heater. You have to get some clean containers to use if you want to re-use it. Gas cans work. Afterwards I used a fork lift to raise the containers high enough to use a syphon hose to refill.