1993 240 Wagon
189k mi

I purchased this car last summer and have enjoyed bringing it back to life. The latest project is fixing the A/C, but I've noticed this winter that I always have warm or hot air coming from the vents regardless of the temperature selected. So I figured I better fix this first and need some advice.

When the selector is on full-cold, the air is warm from all vents and will never give me high 30's from the outside air.

When it's on full-hot, the air is hot. I don't have any issue with getting heat.

The vent selector buttons (defrost, foot, recirc) seem to work just fine as I can feel the change in air flow from the various vents.

I visually inspected the heater control valve and hoses by pulling the kick panel. The value appears to have full motion across the entire temperature selector throw. There is no binding, bending or any other resistance that appears to affect the lever movement on the valve. Everything is very clean.

Can the value appear to work properly from the outside, but not internally close completely, allowing coolant to pass? What else could be causing the constant warm/hot air?

I thought about clamping the hose going to the valve but not sure if that's a good idea.

Any other thoughts?

If I need a new valve, is there a particular brand I should use if I don't want to do this job again.

Thank you.