Car A/C pros, need a little help

[JamieK]

Does the car have a sight glass? It should be in the top of the receiver/dryer. If it does, then the "rule of thumb" is to add refrigerant until you see no more bubbles. This will get you pretty close in the ballpark of having the correct amount of refrigerant in the system and you should be fine for your purposes.

 

[pop pop]

A clear sight glass only means that there is no vapor/liquid phase passing through the sight glass, nothing more.

That could mean no liquid and only vapor, or only liquid and no vapor or nothing moving at all. AIRecall, only the old R12 systems had sight glasses and they appear clear when properly charged (I''ve done this). But with changes in components and referigerant, this doesn't work as a rule. The idea is to have a flooded condenser, but it may not be a good indicator now with the changes made.

 

[KinzeMech]

The sight glass worked on old R12 systems, when using R12.

A converted system charged to the point of clearing the sight glass, using R134a, will almost always be overcharged.

 

[Jason280]

Quick question, any issues with using R12 marked gauges with an R134a system (assuming you have the correct quick-coupler adapters)?

 

[chris142]

Quick question, any issues with using R12 marked gauges with an R134a system (assuming you have the correct quick-coupler adapters)?

all the guages do is measure pressure. don't matter what refrigerant

is being used

 

[Jason280]

That was my assumption, thanks for the confirmation.

I forgot to add in the previous response, but we were able to get the A/C cooling much better in the Mazda. A friend of mine is familiar with A/C systems, and we added a little bit of freon to the truck. The vents are now blowing 42*, which is a huge improvement.