Adding oil before regas

[Z2TT]

A person who is going to regas my aircon said he doesn't add oil unless I have had the compressor overhauled before the regas. He says the old oil would still be there in the compressors sump.

Now I'm wondering

1. Since he is going to use a vacuum pump to evac the system, wouldn't most of the oil be sucked out, requiring new oil to be poored in anyway?

2. Does my compressor even have a sump? This is the first time I hear of him mentioning compressor sumps. I have a Nippon Denso 10PA Compressor from a Toyota, similar to this one :

http://www.alibaba.com/product-gs/231131640/10PA17C_Compressors.html

So I don't know whether it's safe to let him just put gas in the system, because my thinking tells me during the evacuation proccess most of the oil would be removed.

Thanks.

[Gary]

He is correct.

The vacuum pump does not remove oil from the system.

[Z2TT]

Thanks,

To find out how much oil he has to put in, should I remove the compressor and measure how much oil I can drain out of it?

Also since the evaporator has been removed and flushed/pressure tested, how much oil would I have lost from the evaporator?

[Gary]

You don't need to add any oil.

[whiteair]

It's unlikely that you have lost oil out of the system, unless there has been a sudden decompression of the system, ie a burst pipe. I always used to put in a few squirts of oil into the system anyway before a re-gas just to be on the safe side. As already posted, the vac pump will only pull out air/nitrogen from the system. Don't forget to change the drier though.

[xamtex]

you dont need to touch the compressor as its not been removed....as the evapourater has been drained and flushed you should add about 40ml of oil to the system before regassing.
i normally add about 15ml of oil before regassing any system.my machine does remove a little oil when recovering the gas...it is drained off into a measuring jug and usually equates to about 15ml...if i drain more of i replace what amount came out.

[abbsnowman]

you dont need to touch the compressor as its not been removed....as the evapourater has been drained and flushed you should add about 40ml of oil to the system before regassing.
i normally add about 15ml of oil before regassing any system.my machine does remove a little oil when recovering the gas...it is drained off into a measuring jug and usually equates to about 15ml...if i drain more of i replace what amount came out.



He is correct!
With all respect to Gary, they replaced evap and that is were most of the oil will migrate.