[2dinos]

When I do a re-charge of the freon, I always like to check the sight glass to confirm proper fill. Should be zero - to very few bubbles as I understand it, but the sight glass is located by the frame above the right front inner suspension. I use a mirror and a flashlight, but this is a bit awkward.

I was thinking of one of those small USB cameras to look at it on a laptop during the charging. As opposed to scramble, and crouch in there w mirror etc.

Any thoughts? Thanks!

:music-smiley-019:

 

[David @ FluentInFerrari]

Charge by weight or pressure...
The sight glass is of little meaning.

 

[2dinos]

Charge by weight or pressure...
The sight glass is of little meaning.

By Weight
From empty: suck it down for an hour plus - check pressure to see if stable - not boiling off non-condensable contamination, or system has a leak. Then fill with prescribed amount by mass.

By pressure?
Do you check low pressure side while running? And what should it be for R-12? Or ??

Thanks!

 

[David @ FluentInFerrari]

By Weight
From empty: suck it down for an hour plus - check pressure to see if stable - not boiling off non-condensable contamination, or system has a leak. Then fill with prescribed amount by mass.

That works. The spec is in the WSM. (If a leak is suspected, it is environmentally responsible to do a test charge with Nitrogen.)

By pressure?
Do you check low pressure side while running? And what should it be for R-12? Or ??

Pressure is more of a functionality/diagnostic check. Pressures for an R-12 system should be marked on your gauge set. That, and knowing the ambient temp, and you should be all set. There are ranges for both high and low.

 

[2dinos]

That works. The spec is in the WSM. (If a leak is suspected, it is environmentally responsible to do a test charge with Nitrogen.)
I agree on the N2. I did this with soapy water on a home AC install. I've used vacuum holding for an hour + to satisfy. The cars pretty much need charging every couple of years. Funny that 16 year old bmw still blows ice cubes. I'm guessing inactivity of these cars does the AC seals no good ??


Pressure is more of a functionality/diagnostic check. Pressures for an R-12 system should be marked on your gauge set. That, and knowing the ambient temp, and you should be all set. There are ranges for both high and low.

Interesting! Thanks. I take it that it should fall within the range when you rev it?

 

[David @ FluentInFerrari]

Interesting! Thanks. I take it that it should fall within the range when you rev it?

As the compressor cycles, the pressures will vary. We set up a large fan in front of the car to blow ambient air across the condenser. Pressures would be typically measured at 1500 rpm. Other than access to the ports on some of the models, this is a fairly simply procedure and we usually can meet or exceed the specified minimum performances temperatures.