I stocked up on R-12 a while back. Now the system check lens is foamy indicating low refrigerant.

I found a threaded valve behind the radiator at hood level (1/4"?), I found another in front of the firewall, passenger side, which is a smaller thread diameter.

I considered the 134a conversion, but since I have the R-12, and the age of the car, it's easier to top off. Yes, "only a certified technician......blah, blah...". My nieghbor is an HVAC guy so that's covered.

My Haynes manual gives NO detailed instruction, nor does the forum or the web. Where and how do I add it?

 

if your neighbor is the man he should have a clue on which port to add it in....

 

He's not a car guy, he's busy, I'm busy and I need to get it done. He gave me a guage set to test.

Not the kind of answer I was looking for........I want an education from forum members on an illusive topic.

 

Fill it from the low side of the system.

 

I am familiar with high and low. Which threaded connection is the "low" side?

 

fill the one closest to the radiator fan.

 

The High side is usually capped with a Red cap and the Low side is capped with a Blue cap.

 

the high port is by the firewall, the low port is infront by the radiator

 

The small pipe is the high pressure side, the bigger pipe is the low pressure side