Cavalier CS-72 - Freeze Up

[casey]

I have Cavalier CS-72-A. It's been off and in my dad's and then my garage for 20+ years. I finally decided to work on it this past few weeks. I replaced some bad wiring, and it fired right up and gets really cold. It did make a lot of condensation so I replaced all the gaskets. It ran for hours with no condensation. It's amazing how well the gasket change worked. I let it run over night for the first time last night. I got up this morning and went out to check for issues. No condensation, but the inside blower has ice all over it. What should I do? When I check with a laser thermometer the temperature is 19 inside. Would a faulty thermostat cause the ice over?

[johnieG]

Hi Casey & welcome to the site...

While a bad (shorted or stuck-on) thermostat can cause evaporator icing, it might be the suspect if the compressor doesn't shut off between cycles ( runs continuously)

also keep in mind that it could be (Looking at the overall frosting of the coils) a bad evaporator fan-motor ( no airflow over the coils) check to see that its blowing air out the back. with no air-flow, the coils will quickly get too cold & short-cycle the compressor ( doesn't run long enough)

or it can be caused by the system being over-charge with freon , an over charged system with too much freon will cause the evaporator to be flooded with refrigerant that doesn't evaporate completely back to a gas & cause the icing you see, notice that the icing goes all the way back down the suction return line heading towards the compressor.

I see an add-on type of service valve on the Suction line, makes me suspect that it's been recharged

[casey]

Thanks so much for your help. Yes it was the thermostat. Mine doesn't have a knob and I hadn't thought to mess with it. I turned it down about half way and now it's running perfectly.

It hasn't been refilled with freon in the past 20-25 years. I know it was repainted red by coca cola.. I read somewhere online that coca cola repainted some of the cavalier 72s in the 1970s.  Maybe they charged it up then too.