MG MGB and MGB GT Tech Talk
Ok, this may have something to do with a MG if it's equiped with an A/C.
A lady here at work needs freon (R134) in her 97 Suburban. I'm sure it's not hard to do, but does anyone know the location of the low pressure side? Will I be able to tell the low pressure side? My 90 Honda had fittings on both the high side and low side (but they were marked).
Is it the one with the dryer?
Not sure of that exact setup Steve, but receiver/dryer (usually with sight glass) will be on the high pressure side after the condenser. Low pressure side will be connected to the evaporator. Later systems may have an 'accumulator' in the suction (low pressure) line which may resemble a receiver/dryer.
I'm sure no expert, but have learned a little recently when fixing the A/C in my GT. BTW thanks for the compressor - it helped in the learning process!
Take safety precautions - R134a has some pretty high pressures.
Thanks!
I just looked at it and the compressor has two connector fittings on it. One looks almost exactly like the kind you'd use for a home air compressor. From what I've read, this is the low side, and the connectors you'd use to add freon make it "idiot" proof.
The fittings are different sizes to keep you from hooking up wrong. If you're using a set of guages keep the high side turned OFF. You'll still get a reading of the high side pressure, but it cant feed high pressure into the can and possibly explode it. If you're using a little "Wal-Mart" suicide hose keep a close eye on the sight glass and as soon as the bubbles disappear shut the can off.
John,
I added two cans to the system (the kit was a breeze to use). The aluminum hose began to cool down and sweat, but it never got cold inside! Should I add another can? On the dryer it said the system can hold 4lbs, but I only added 28 oz. I could tell the compressor was being affected because it got much quieter. I don't know how long she's been out of freon.
Is there any other reason you can think of why it wouldn't cool inside?
Don't put any more in or run the compressor before putting in a can of 134a "Oil Charge". If the system leaked all the way down it lost some oil too. Charging without adding oil will likely burn up the compressor and that woud mean a new compressor, reciever/dryer, and condensor plus flush the rest of the system. The new condensors have such small passages they can't be flushed out.
What you did looks right so far, and the system responded as is should. cold discharge pipe, but not cool inside yet. When your get it charged right there wil be no bubbles in the sight glass and the upper vent outlet temperature should be 49F or less. You don't want to go below 44F or the evaporater will freeze up in humid weather.
You have to run it wile putting in the oil charge and that's OK, but don't finish filling it or try to use it before the oil is in.
Thanks for the words of encouragement. The stuff I used had about 2oz of oil in it, and some sealer (in case there was a leak). I saw the oil charge stuff. Is that better than the stuff with everything in it? (which is probably about as good as combination shampoo and conditioner!).
By the way, there isn't a sight glass that I could see. I think they did away with them when they went to R134?
