I'm rebuilding the HVAC behind the dash on 'ol Rembrandt ('96 Ram 1500/5.2). Not replacing the compressor or condenser or lines (nothing leaked, but blend door failed n evap core clogged). Orifice valve and accumulator onwards going. I've got a 'rebuild kit that came with my new accumulator, including new PAG oil. Recommendations on draining out all old oil n starting over or not necessary???

 

BTW, I have the factory service manual. But it's vague, if the compressor ISN'T replaced.

 

I'm no help but curious, too. Seems to me all you can do is either hope there's enough in the system or flush it with the kits specifically for doing so, so you KNOW all oil is out of the system.

Supposedly most of the oil stays in the compressor. I have a hard time understanding how this is possible, but I'm new to a/c service.

Let us know what you do - if nothing else I need to learn!!

 

Replacing the oil is a bit of a guessing game, There is a chart either in the service manual or on line that will guide you in adding oil. If the system is opened it's wise to replace the receiver/dryer.

 

I'm hearin' ya brother. I've already got a new receiver/dryer n am accounting for the new R/D and evap core. I'm wondering if I need to drain and refill the compressor. I'm not replacing the compressor.

 

It's been about 40 years for me since I last did this stuff. I just don't wanna risk smokin' a perfectly good compressor with too little oil, or reduce the efficiency of the A/C with too much oil.

 

Then do the extra work, and give yourself some peace of mind. Pull the compressor, dump any oil out of it, and start fresh on the whole system.

 

I don't believe too much oil will kill it, but you don't want so much in there that it floods the system.

To deal with your issue, I'd try dumping all of the old oil and starting over refilling each item, since the evaporator was clogged and there could be some minor amounts of metal debris in the oil, especially since you're not replacing everything in the system (compressor, etc.).

 

when i replaced my evaporator i cut the receiver/dryer open to see how much oil was in it. If there is any debris in the system it will be in there, They also act as a filter. After i got the evaporator in i added oil to the receiver/dryer then evacuated it and filled. Been running fine for the last 10 years. If there is any debris in there should be your deciding factor if you want to check the compressor.

 

When I say...'the evap core was clogged', I meant on the outside. Leaves n other such schmutz! Just lookin' for ways to truncate the job. It appeals to my 'minimalist attitude', not to mention time investment! LOL! The heater core is like brand new. Clean, inside and out. Brass, copper n steel. Not some replacement abomination. I'm keepin' the old heater core!