A/C conversion question

[ahlem]

I had to endure 400 miles at 90 degrees F with a complaining family member yesterday. I need to get the A/C working. Bavauto sells a kit. Before I drop $150 I wanted to put on the new fittings from the big box parts store and run some dye to see if there was a leak in the compressor. Is this a good idea? With the new fittings I plan on testing the system with the cheapie guage that came with the 134 recharge for another car. Anyone have a write up on the conversion? Hopefully the compressor doesn't need a rebuild and just some O rings. I have three e30's and a Chevy van that all need A/C work too. I may become an expert or really stupid or broke by the time I'm done.

[Tiger]

There is nothing really special with AC. I suggest you buy the $60 conversion kit sold at your local auto parts store. You will need extra R134 cans. Cheapest source is Walmart.

To test your system you need to have vacuum pump. You need vacuum pump before you fill any system with refrigerant. A simple low pressure gauge with vacuum reading is all you need. Autozone loans vacuum pumps for free.

Hook up the vacuum to the high side and let it suck out your system... should get to 28 or even 30 mercury inch. At the same time, you hook up the low side with your gauge but leave the refrigerant can in off position. You will need to let it vacuum for 20 minutes...

Then turn off vacuum pump and wait 10 minutes... if it hold vacuum steady like 25 at the end... then your system is good to refill. If it keeps losing pressure and goes under 20, you got a leak.

Now when you refill your system... you need to keep track of your weight... if the sticker said 2lb 2 oz. You will need about 34oz... but 32 oz is probably all you need. Remember, this weight includes the oil can you inject... so if oil can is 2 oz... then all you need is 32oz refrigerant. Don't forget oil... you will lose some in many ways.

For initial filling, keep can upside down so the vacuum in the system suck them in fast. By the second can, it probably won't suck in all... All you need is about 60PSI so the compressor will turn on. You do this injection with engine off.

From here on, can must be in upright position for gas injection... with compressor kicking in... car windows closed... you are looking for 28 PSI... you need to inject refrigerant so it get up to at least 25PSI or your evaporator will freeze. Then after couple of minutes... bring it up to 28PSI... should be icy cold air.

Lots of tips on internet... do a search.

[whiskychaser]

http://www.rscool.com/RS-24.html
Works for me :-)

[Blitzkrieg Bob]

Walmart and many places sell the R134 adapter sets for less then $20.

Don’t use any kind of stop leak…Bad stuff in the long run.

Try to get a proper A/C gauge set/manifold with low & high side gauges. This will help trouble shoot bad expansion valves or worn compressor problems and reduce the chances of blowing the high side. ( these cars are getting old and an over charge can turn a leak into a hissing cloud of R134 in your face)

If the system is not totally flat, ( compressor engages, but little to no cooling) I suggest just topping it off with one can of R134 and dye to charge and check the system for leaks. Follow the instructions on the cans. Dye goes in upside down and R134 alone goes in right side up. (Liquid vs. vapor).

Do the dye first and then add the R134 as needed…A totally flat system won’t engage the compressor until there is about 15-20 psi and once filled the Low side should read @ 40 psi and high @ 200, it may take 3 to 4 cans to fill an E34 a really low system.

Once you find the leak ( this may take a while if it is really slow, but the dye will show under UV light.) Remember to replace the dryer when doing any work the will require opening the system up, evacuating and charging. Ie. Replacing the Compressor, condenser, evap…Buy extra O rings, they get lost some times in the R&R process and you want to close up the system and evacuate it ASAP.