A/C Charging Write-Up??

[911blex]

Originally Posted by entropy

If you're budget is limited it can be simpler. The above thread is very technically correct, but in reality you could buy a cheap 928 for doing everything perfect. R134 is a smaller molecule and will slowly (and I mean slowly) leak. It is supposed to be updated with PAG oil, but I've never seen a problem with old oil like the guidelines suggest. Freon carries the oil with it to lubricate the system, including the o-rings at the joints. Since the compressor is the lowest point, and has it's own oil bath, you can send 12 volts to the connector to see if it kicks on ok. It won't hurt it to run 5 or 10 seconds. If it passes, by the guages above and a vacuum pump for $80 from harbor freight and a set of adapter fittings from somewhere like autozone. If there's moisture in the system (receiver dryer etc.) a long enough vacuum will boil the water out. If you're not in a hurry leave it on for 45 mins. or so. When you're done add freon and see if it runs. Unless you have a substantial problem, it's cheaper to buy a can and top it off once or twice a year. Don't turn the freon can upside down while charging. The liquid injestion can hydrolock the compressor. Make sure you charge it thru the low side (big tube) fitting. It can be a pain sometimes to get all the freon out of the can so you might want to have a blowdryer nearby to warm the can with to get it all out.

All great tips IMO, I place my cans of refridgerant in my kitchen sink filled with warm water before filling an A/C system to get as much refridgerant out as possible.

If a person wants to do things on a budget and make their life easier, I suggest sticking with your old R12 system as you won't have to buy any service port adapters or other stuff that R134a requires. Just buy 3 old 16 ounce (1 lb) cans of R12 refridgent off ebay, craiglist, or at a swap meet. A lot of times the people who are selling it just want to get rid of it and wll throw in their dispenser for free.

Have a friend sit in your car while you fill you a/c system on the low side service port and have him/her let you know when it gets cold. If I remember right, the refridgerant capacity is just over 2 lbs on most 928s (look at the sticker in your engine bay) so the a/c should start to get cool by the end of the 2nd can if your system is really low. If you want to get fancy, rent or borrow a friend's leak detecter and go around your a/c system to see if there are any large leaks so when you your system leaks the refridgerant out you will know which components you need to repair/replace on your a/c system before you fill it up again.

[SolReaver]

Hey guys. Careful about warming freon cans. it increases their pressure and there is a risk of explosion. Protect yourself accordingly. Another option to the leak detector is the colored dye. A black light shows the leaks.

[devilinblack]

At a minimum, buy the gauges and find some R-12.

134a is not compatible with the mineral oil used with R-12 and will lead to compressor failure. Maybe not tomorrow, or even next week but is there really a point in doing this half assed and having to do it over again?

Some reading to be found here: http://www.allpar.com/eek/ac.html