Where is bunk air valve on 2000 Freightliner FLD 12064ST ?

look under cab/sleeper. There are coolant lines running to sleeper heater. Look for H-shaped valve

 

It will have an air line to it, many times you have to remove the cover to see it, If it goes bad it will continue blowing air into the cooling system when the truck is shut off. I would say it is a "T" shape the coolant makes a 90 degree turn threw the valve. To test it without dismantling it I use to put an air line in the system from the heater control in the sleeper dash, with a guage in it put in the air, close the ball valve, if it leaks down and there is no leaks at the fitting it is Junk
Just a thought!

 

It's right at the heater core only about 3 inches of hose between it and the core and it has an air line and wires going to it.
Need any help finding the heater core? It's under the bunk, passenger side.
Need directions to the bunk? Hahahaha.

I re-plumbed mine and used a Kaiser valve like on the cab heater line and tossed the electric over air valve.

 

ted,
did you ever find the location of that bunk air valve? I also have a 2000 fld-120 with detroit 60 series and now having the same problem. I have pressurization in the cooling system and leaking drops of antifreeze from the overflow hose on the radiator cap. I have to add antifreeze to the radiator often.
I'm trying to locate that "bunk valve" to swap it and see if this fixes my problem of the cooling system.
in the fld120 is the "bunk valve" air operated or electric?
any help you can give is appreciated in advance.
thanks
tony

 

The air valve is right next to the bunk heater core. Just lift your bunk, the heater box is on the passenger side. You will see a little plastic valve in the heater core hose with an airline going to it. I believe it is the only airline in that area. You can see if it's your problem by taking the airline off and plugging it.

 

thanks much for your help. I will go due this today. hopefully this is my problem. I will keep my fingers crossed.
tony