1998 V70 AC PAG oil adding question

vcowens · Post by **vcowens** » 29 Jan 2015, 17:20

Hello Everybody. I am about to try and charge my 1998 V70's AC after a catostrophic hose failure. ( I only plan on changing the blown hose and drier) I plan on using the gauge set from Harbor Freight. Ive done a lot of research on the topic and my question is: If I add the required PAG oil (liquid, not aerosol) to the system before evacuting the system, won't all the oil be sucked out during evacuation? Also where would I add the PAG oil? The drier? Should I just use an aerosol PAG oil?

Post by **Ozark Lee** » 29 Jan 2015, 17:38

I've added it both ways. I add it to the receiver/filter/drier and the compressor if it is in the liquid form. The oil doesn't get totally sucked out when you pull the vacuum but you will lose some. The pressurized stuff is much easier to use but you wind up guestimating how much is added when it is less than a full can. You can usually guestimate close enough based on how much fluid you can feel in the can and just run the percentages in your head.

I add the pressurized oil first thing after the evacuation vacuum, before the compressor is run.

...Lee

Post by **cn90** » 29 Jan 2015, 17:53

I replaced the AC Compressor in my 2007 Honda Odyssey recently, all these questions (and answers) are in there, same principle as your Volvo 850...

http://www.odyclub.com/forums/52-2005-2 ... ement.html

Post by **abscate** » 29 Jan 2015, 18:53

When I did mine I pumped it down for a few hours, checked for leaks, then reopened it, added full amount of PAG oil to the receiver, closed up,and pumped down again for a few minutes.

The vapour pressure of PAG is so low you will lose a tiny amount.

My AC has been working great for 2 years after this

vcowens · Post by **vcowens** » 29 Jan 2015, 20:45

Was a flush performed? If so, how much solvent did it take? That stuff is rather expensive. I'm sure mine could use it since it is 17 years old. I just don't want to buy a whole gallon if I don't need to. Thanks for everyone's help.

Post by **Ozark Lee** » 29 Jan 2015, 21:24

Unless the compressor detonated there really isn't any reason to do a flush. Age doesn't bother refrigerant but if the compressor comes apart internally it distributes debris throughout the system. The standard procedure after a compressor failure is a flush but no other failure requires it. With a Volvo the design of the condenser coil is such that it doesn't flush well anyway so replacement is the best course there when the compressor fails.

A burst hose doesn't necessitate a flush and doing so could cause more trouble than it would prevent. Changing the receiver / filter / drier is a must and changing the orifice tub is suggested but beyond that just pull a good vacuum, add the prescribed amount of oil, and recharge the system. Don't overcharge the system and pay attention to the ambient temperature when you do A/C work in the winter. The winter pressures will be quite a bit lower than summer pressures and you can wind up overcharging the system if you use "rule of thumb / conventional wisdom" pressures. Using weight is always your best bet and that is particularly true in the winter.

...Lee

Post by **abscate** » 30 Jan 2015, 04:37

Search jimmy57 posts for the correct way to measure AC pressure. A lot of people screw this up by not equilibrating the system to " standard conditions " to determine correct fill.

vcowens · Post by **vcowens** » 30 Jan 2015, 16:06

Well I just opened my package from IPD containing my new hose and drier and found the hose to be in in a bag but the drier was not. The drier also did not have any caps or plugs on it's inlet/ oulet. My question is whether or not the dessicant has been compromised. The drier sat in my house in the box for about 5 weeks. I was planning on getting this done tomorrow and I don't think I can get another drier this weekend. Any opinions on the integrity of the dessicant?

Post by **Ozark Lee** » 30 Jan 2015, 16:49

The lack of plugs on the drier is pretty common these days but it is my understanding that the desiccant isn't activated until it comes in contact with the PAG oil. The last one I bought came in the same way and it hasn't given me any grief.

...Lee

Post by **abscate** » 31 Jan 2015, 02:56

I think the desiccant is just silica gel. You can pump down the system for an hour which will also remove residual moisture from the desiccant.