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Re: AC system fix confusion Posted by JerseySaab [Email]  (#666) [Profile/Gallery]
(more from JerseySaab) on Wed, 26 Jun 2013 09:40:02
In Reply to: Re: AC system fix confusion, steve, Wed, 26 Jun 2013 08:34:01 Members do not see ads below this line. - Help Keep This Site Online - Signup |
The Nylog video I saw showed actually taking out the valve cores, pushing the stems to open them, and slathering Nylog on the sealing surfaces. The way I learned it, however, is that the valve cores are not expected to make 100% seal, that is the job of the service valve caps. (I do put Nylog on the o-rings in the caps.) Still it obviously cannot hurt to have a better seal there.
Liquid oil in hoses should come out, though some will cling to the inside. Probably a drier is not going to release all the oil it has trapped inside. General rule of thumb I've seen is usually 1 oz. oil for the drier, 1 oz. for condenser, 2 oz. for evaporator, 2 oz. for compressor, .5 oz for each hose. The vehicle manufacturer may have more specific guidelines.
The only way to be 100% certain of the oil level though is to flush it all out and start over, or replace all the parts in the system and use all new oil. There is a gadget that purports to detect oil level in the system, I've provided a link to it. (I've never used it and don't know how accurate it is.) There has to be some tolerance for the oil level since as far as I know it is not standard practice to flush everything out at each service.
You can just pour the oil into various parts before closing up the system, easy if you're using a syringe. The compressor will normally have a removable plug where the oil goes in. You want oil in the system BEFORE the compressor engages! Modern compressors don't really have a sump like the old reciprocating monsters, only a small amount of oil will stay in them. They depend on the refrigerant to carry the oil and provide lubrication.
In a car with variable-displacement compressor you are probably better off with a slight undercharge than overcharge so you will probably want to round down, though I doubt that a gram or two is going to make a difference. (An ounce or two will!)
I have not used a recharge machine so cannot comment on the best way to use it, I charge manually through the gauge set. Normally after pulling vacuum for a couple of hours and then purging air from the gauge set fill line, I let the vacuum pull in the first bit of refrigerant from the can. Heating the can in a pan of warm water helps this process. This will usually provide enough pressure in the system so the compressor can switch on, and that pulls in the remaining refrigerant, thought the compressor can be briefly hot-wired if necessary.
When doing it this way a scale really should be used to determine how much refrigerant is charged in by weight. My cars are old though and do not have variable-displacement compressors so in my case an approximate charge will generally do the trick, I just watch temperature and pressure.
, Tue, 25 Jun 2013 09:14:40, Tue, 25 Jun 2013 10:05:36, Wed, 26 Jun 2013 07:36:53, Wed, 26 Jun 2013 09:40:02 <-- Viewing This Message, Wed, 26 Jun 2013 14:17:21
, Tue, 25 Jun 2013 19:06:29, Wed, 26 Jun 2013 04:51:45
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