a/c compressor oil

[mesallem]

hey guys i just replaced my ac compressor with one from a 1994, which is a r134 compressor, anyways, i was wondering how do i put the oil in the compressor, the guy in the shop told me to use an oil charge that goes in the low side port, i think its called PAG oil, i did that but it seems as if there is still not enough oil in the compressor, when i turn on the A/C it sounds like the internals are scraping, it only scrapes once in a while not all the time, what i am asking is was the auto parts guy right? Should i add oil? where should i add oil from?

[qship96]

how much oil did you add with the new compressor?was the compressor new,used,rebuilt,or where did it come from?

[DrewQ45]

You add the oil from a bottle into the suction port, which happens to be where the top hose is connected. Add the oil then connect the AC hose. I hooked up a clear hose with funnel then poured from up top.

[elwesso]

So let me ask. When you replace the oil, it actually says that you can just add the extra to the compressor. For instance, if you replace the dryer its 5mL and then whatever you pulled out of the old compressor. What do you use the oil charge for?

[DrewQ45]

So let me ask. When you replace the oil, it actually says that you can just add the extra to the compressor. For instance, if you replace the dryer its 5mL and then whatever you pulled out of the old compressor. What do you use the oil charge for?

You add what you remove but hopefully, it wasn't low to begin with.

I would only use an oil charge if I had prior knowledge of the type of oil used and the intial amount contained. I didn't have to do any guesswork since I was switching to R134 and had to purge the system anyway. I used ester oil in case my switch to R134 wasn't satisfactory. It works with any type of gas so theoretically, I could switch back and just top off the oil.

[mesallem]

if i take off the low hose off the compressor, wont it evacuate my system of refridgerant? should i through another oil charge into it? man this sucks lol

[DrewQ45]

if i take off the low hose off the compressor, wont it evacuate my system of refridgerant? should i through another oil charge into it? man this sucks lol

By law refrigerant needs to be recovered (vacuum) by a shop and not released into the atmosphere. Whatever oil gets removed during recovery is what you'll replace.

[maxnix]

if i take off the low hose off the compressor, wont it evacuate my system of refridgerant? l

No. As I recall, the respective FSM specifies a different oil for each type of refrigerant.

As always, go with the FSM recommendation, unless you know better.

[elwesso]

Yes it will. If you remove the low side hose on the compressor gas and oil is gonna come out. Trust me, I about took a picture and sent it to Al Gore!

Anyway, you can get oil charges. Ive been learning a lot about AC recently and heres what ive come up with.

If youre replacing the compressor you add the necssary oil to the system directly into the compressor. So whatever you need to add to the compressor + whatever the FSM specifies (it tells you how much you need to add based on what components youre replacing)... You add the full amount to the compressor.

However lets say you dont need to mess with the compressor. You can get cans of oil that will let you charge it into the system. So lets say you replace a dryer. The FSM calls for 5mL (which is about .16 oz) of oil to be added, you can get one of the oil charge cans and add it that way.

In my case, I have an AC compressor that already has oil inside it so I dont have to add any oil. It says tampering with the oil level will void the warranty.

[DrewQ45]

Yes it will. If you remove the low side hose on the compressor gas and oil is gonna come out.

Removing the hose will drain it somewhat, but there is an actual oil drain plug on the compressor. I believe it sits at the back (opposite end from the pulley) of the compressor at the lowest point and if the front end is jacked up, it allows complete drain without having to remove compressor from car.

[maxnix]

Yes it will. If you remove the low side hose on the compressor gas and oil is gonna come out.

No, it will not completely evacuate the refrigerant like a vacuum pump will.

[elwesso]

I think he was asking if refrigerant would come out. in which case it will.

Technically speaking, when you evacuate the system you arent pulling a vaccum you are just "letting" it out. The vacuuming is a seperate step. On most vacuum pumps if you put a positive pressure on them they will not be happy (specifically mentions that on my pump)

[AlabamaDan]

There's oil in the AC? How often should you have the AC serviced? That's not on the Ultimate Q45 Maint Schedule.

[DrewQ45]

I think he was asking if refrigerant would come out. in which case it will.

Technically speaking, when you evacuate the system you arent pulling a vaccum you are just "letting" it out. The vacuuming is a seperate step. On most vacuum pumps if you put a positive pressure on them they will not be happy (specifically mentions that on my pump)

You can't just "let out" refrigerant. It's illegal. Shops recover it (usually for free) by hooking up a vacum pump.

[qship96]

Reading thru this thread confirms that you are better off leaving all a/c work to a trained professional!