OT: AC Advice

The acid would come from the oxygen in contact with the oil and moister in the system thats been sitting empty for a year.

The hose having been sitting with enough mineral oil to keep them sealed up for what little the flushing solvent would take away.

If the system was run with solvent for for several hours then I could see your point and providing the hoses hasn't been changed with the new type hose.

I guess I'm pretty much set in my ways as I don't like doing the job more than once.

T_Bone

What you are seeing is called mineral sludge acid. You have used a refrigerant that was not fully compatable with the mineral based oil in your system along with moister in the system.

Most R134A refrigerants require a ester based oil. There refrigerants that claim to be compatable with mineral oil but that remains to be seen.

You could have also let moister into the system that reacted with the refrigerant and the mineral oil as you didn't recharge the system for a year. It would have been useful to leave the system with a small refrigerant charge.

You now have a huge mess on your hands. I'll give you my best SWAG of what might help.

Remove the expansion valve and dryer from the system. Install a new dryer. By-pass the expansion valve. Pull a quick vaccum to 25hg then charge with R11 or R124.

Circulate the R11 at 1500rpm for about 1/2hr with the system on high then dump the charge into a waste refrigerant cylinder.

Take off the compressor and dump the oil in a approved container. Wash the compressor internals with R11 a couple times.

Intall the compressor with 6oz of ester based oil.

This will be some very nasty acid stuff so don't get it on your cloths or skin.

Replace the dryer and expansion valve, vacuum to 28hg, then charge with dry nitrogen or Co2, dump that charge then vacuum to 29.925hg then fill again with dry nitrogen. Let sit for 15min. If no pressure loss then the system is leak free.

Dump the nitrogen charge then add 4oz of ISO 300 Ester based oil then recharge with R134A or R401A.

Refrigerant charge is correct when the high side is reading 30� over ambient temperature when the compressor is running at 1500rpm with good air flow over the condensor.

Anything less than the procedure listed will just be wating for the next plug up to happen.

T_Bone

If both aren't sweating (amount depends upon temp and humidty) you are low. If you notice a very abrupt line or change in sweating characteristics on the side of your accumulator you are looking at your ref level. Additionally, you feel them with your hand and they are cold, really cold.

I think what's happening is you are low and after that distance, the engine compartment is heated up pretty good. This heat is absorbed by the accum and hose and competes with the freon temp. Since the system works on proportionality, the 30 degree below ambient that your evaporator is attempting to maintain is partially defeated by the engine heat. Were the system full, it would have enough BTU capacity to accommodate it. Makes sense. Some mfgrs insulate the accum and suc line. My wife's Tahoe is like that. Helps preserve the BTU's. My Dodge truck has the line insul, but not the accum.

Mark

Mark

Don't know if your ref. is restricted. If not you might attempt it yourself. You can still buy the parts at the auto supply, with the exception of the ref. Probably the guy at the counter can tell you how much oil your system takes (if rotary type wobble box) compressor. Probably need a full charge as the other, being old and viscous, will probably wind up in the filter/dryer. Can't get too much oil from the compressor standpoint (more or less as the returned ref. does cool it, but the returning oil is cool too). From a performance standpoint it competes with refrigerant and reduces cooling. But where it's noticeably too much I have no Idea.

Mark