Any A/C experts?

[Master Hack]

Don't know if this is the right place to ask but it's engine ish. Classic Auto Air started blowing warm. Was fine on Thursday, hot wind on Friday. Already disabled the sketchy electric water valve with a 1/2 full port ball valve, so I know that's off.
Fan blows and compressor still engages the pulley so as I understand that means there is still adequate refrigerant yes? According to CAA website the high/low pressure switch will not allow the compressor to engage if too little or too much refrigerant, so that has me thinking it can't be a leak problem. The website troubleshoot just says if the compressor kicks on, check water valve, and I know that's not it. Any ideas?

 

[Nos681]

I suggest getting a set of gauges to see your low and high pressures.

I have Classic Auto Air under dash unit daily driver with a serpentine 508 Sanden compressor.

The ‘65 sits in a non-heated garage during winter…darn cold sometimes too.

The a/c was not working optimally back in April, but I did not have time to mess with it before a road trip to Colorado.

Apparently, I must have lost a minor amount of refrigerant due to extreme cold weather. Did not find any leaks last week while troubleshooting.

My compressor did engage and tried to cool, however there wasn’t enough refrigerant in the system according to the high pressure side gauge…like barely making high pressure.

Used old reference pictures when I did initial 2021 (May).

I did not want to just add more without information to guide me to do so.

I also checked the binary switch and wiring behind the grill too, no issues.

Hope this helps.

Low side ~ 25-50 on R134a scale.
High side ~ 82-100 on R134a scale.
RH center vent = 40F

Expert by no means.


Found this chart online today.

 

[Mustang_Charlie]

As suggested, get yourself a set of gauges.
It is probably low on refrigerant. It can be a little low and still have enough to trip the pressure switch so it will run, but not enough refrigerant to adequately cool.
If you were closer, I would say bring it over, as I have everything here.

 

[Master Hack]

Thanks I may just get some gauges and learn how to use them. I may come back after Amazon delivers them this afternoon HA! Any particular brand recommendation? I have an a/c tech buddy who owes me a favor (or 10) because I gave him my 289 for his Falcon project, but the bastid is not answering my text.

 

[Mustang_Charlie]

Sorry, no recommendations. My sets are probably 30 years old. But any set should work.

I’ll keep an eye out, and help all I can.

BTW, I am just south of Raleigh, NC.

 

[money pits fixer]

Thanks I may just get some gauges and learn how to use them. I may come back after Amazon delivers them this afternoon HA! Any particular brand recommendation? I have an a/c tech buddy who owes me a favor (or 10) because I gave him my 289 for his Falcon project, but the bastid is not answering my text.

You can buy refrigent at a parts house with a gauge on it . They work pretty good if your just correcting the charge .
Even if you purchase a set of automotive gauges you might have a problem with a cylinder of refrigerant to use .