cheez

So I've just picked up a SWEET '87 pickup with a 22re. There are heater issues. From what I've read, the classic failure of the early (pre '89) brass valves is the plunger either seizing or leaking causing the cables to disconnect from the levers. I've yet to find a thread on this issue which did not result in a stuck valve. Nor have I found one in which the heat is constantly on rather than stuck on cool air.
My problem includes the symptoms of broken/disconnected cable behind the dash, but from under the hood I can actuate the plunger with no results. My heat always blows hot. That's right, hot. not cold.
Other than this, there are no cooling system issues or leaks.
I'm stumped. I plan to start replacing parts with the valve first, but I figured I'd see if anyone has some advice for me. Has anyone disassembled one of these? are there seals on the plunger that could deteriorate yet still allow the plunger to move?

arlindsay1992

iTrader: (8)

Unless you have A/C, hot air will come out the vents in the summertime, even with the temp selector set to cool. Cool just blows air at you from outside and the intake is right in front of the windshield (aka, above and behind the engine). If you set it to hot in the summer, then it will be very, very hot.

arlindsay1992

iTrader: (8)

Of course, it's not very difficult to remove the heater control lever assembly and check to see if the cables and levers are moving as designed, then follow each cable to where it ends and see if it's moving whatever it's supposed to move.

cheez

Thanks for the reply, but that's pretty basic stuff. give me some credit here. The air is VERY hot all of the time. I don't fancy pulling a 27 year old dash to see where the cables go, but I guess I have to. I removed the ash tray and the control unit to see what was going on, which is how i described the issue. I guess I'll grin and bear it until I find an un-cracked dash and kill two birds with a single stone. I'm going to try and pinch off the heater core inlet hose so as to simulate the valve functioning correctly to see what happens. If there are any revelations I'll post em up in case someone has a similar issue.

cheez

Problem solved. The plunger had siezed in the valve and come completely off of the rod that the cable is attached to, rendering all of the messing around I was doing with the cable completely useless. Swapped a 89 or newer plastic jobbie in that i picked up at the junkyard for free. I love it when the guy working at the desk has no idea what you grabbed and just says "that?...have a nice day." now to get my AC working again...

4.7_22re

@cheez So im having the same issue with my '84 pickup... does the swap from the brass to plastic heater control valve work, was it a direct swap, or did you have to replace hoses as well? I have tried looking for info on this on several forums and havent had any luck.