I'm running into conflicting advice about what the sight glass should look like after switching from R12 to RedTek.

I had the R-12 in my '87 Westy system removed and a vacuum pulled, then put the adaptor on the low side plug and started installing the RedTek.  After a couple of cans and the can of leak stop, with the AC running full bore I was getting low-side pressure above 40, but according to my calibrated hand, no significant cooling from the vents.  The AC fan was running and the low-pressure tube out of the compressor was chilly, but not really cold.

Looking at the sight glass I saw lots of bubbles, so I assumed I needed to add more coolant, and did a bit more, but no more cooling.  

Shut down after about half an hour and noticed the low pressure valve adapter was hissing.  When I unscrewed it, that stopped, but I wondered how much coolant had leaked out.

I called the RedTek help number and a man in tech support said he wasn't too familiar with the automotive side, but on some Vanagons I might need low side pressures over 50 psi.  They also recommended running it again after it sat overnight in case there was some crud floating in the system that needed to settle.  They are shipping me a replacement adapter and some more refrigerant.

I borrowed a digital thermometer the next day, started the engine and ran the air conditioning to see if there was any difference.  With an air temperature in the garage of 74, the AC was blowing 54, so it is cooling some.  I thought it should drop 40 degrees below ambient if it's running OK.   Again, lots of bubbles in the sight glass.

Then I ran into a note which indicated that the sight glass is not reliable for RedTek, because it's much lighter.  They said I should expect bubbles, and might actually have too much refrigerant in the system.  They recommended letting enough out to get the low side pressure down to below 40 and see what happened.

So - if you are running RedTek, what does your sight glass look like?

- Mike

Mike Finkbiner            
'87 Westy
Moscow, Idaho 
mike_l_f@hotmail.com         

                   You can't see a thought, you can't measure, weigh, nor taste it - but thoughts are the most real things in the Galaxy.
           - Richard Baslim