Thomas Ward

I recently paid to have paid to have my system converted to r134a cause my ac was blowing warm air. After the conversion I still had warm air. The mechanic told me it my be my blender doors. After a little troubleshooting myself I've found my low side is ice cold(by the valve), I also found its cold by the expansion valve inside the AC unit, but then after that there is no coldness in the system.

My mechanic friend told me if I clamp the hoses by the firewall for the heater core that it would cut off the heater core and the air should go cold and that that would let me know if it was a blender door stuck or inop. I tried this and the air stays warm.

I'm leaning at a bad expansion valve but my friend told me if I had a bad EV that I would abnormal high and low pressures but the place that converted my system said my high and low pressures were good.

So please if someone could help it would be great cause Georgia is getting really hot right now... Thanks in advance.

PredatorZ

Clamping a hose will kink it and eventually cause a leak, many have installed a valve on the input side to the heater core, then all you have to do is open it for winter and close it when it warms back up. Go to your local hardware store, everything you need is in the plumbing dept.
The valve that normally turns off the hot water is located next to the heater core, usually operated by a cable from the dash controls. it is possible the cable came loose, either at the heater control, or the valve, on each end is a small snapping clamp that holds the control cable in place, if one popped loose it wouldn't open or close and it would feel pretty much normal.

zxguy1986

Also check your vacuum pump and hoses. That system operates the air distrib system and the air dampers behind your vents. All your hoses are OK and are correct diameters? See Thumper's guide at Vacuum Lines Also your FSM has major troubleshooting instructions for your A/C.

If push comes to shove, you can loop off the hot supply to the heater core for the summer and do it on the engine side of the firewall.

Do you know if you're getting cold refrigerant up to blower level? If so, getting cold air from your vents is probably a damper operation issue, my guess. Sticky damper. You might jog your dampers into working right, blower on, if you toggle the driver's side floor vent slide switch up and down a few times (it's in front of your right knee) and leave it in the down position. Works in my '86

Thomas Ward

So just to clarify when I clamped the hoses it didn't help so doing anything to limit the heater core shouldn't help my issue.

Is the condenser suppose to be cold? I haven't felt it to check. I know the hoses into the ac unit through the fire wall is super cold.

Is the Evaporator suppose to get cold?

zxguy1986

Yes, evap is cold if all valves are working.

Thomas Ward

Ok so took the panel off behind the glove box where the expansion valve is and the expansion valve is cold along with the large tube under it that wraps around the back side. however the evaporator isn't cold at all.

zxguy1986

According to my '86 FSM diag HA-9, the expansion valve controls the amount of refrig spray to the evap. If evap is not cold, the expansion valve is closed and delivering nothing. If your blower is on through that, you may have a bad/stuck expansion valve.

Thomas Ward

Ok so after I ripped out my dash I replaced the expantion valve and gutted the throttle suction valve. The tsv was guts were corroded and stuck in place. After all that I took it to the shop had them flush and recharge. After all that my AC is now working!!!!!! I'm about 95% sure it was the tsv and not the expansion valve but I changed both while I was in there.

PredatorZ

Way to go Thomas !, now you can bask in the coolness of your hard work.

zxguy1986

Aha. I predict you will survive another Georgia summer. Come back in the fall and we will re-do everything!