4montecarlo

I had a leak in my ac system, and now i need to add freon. i fig i would try to use the vaccum pump first and add freon and pag oil. the guy at AZ sold the pag oil that is not in a typical pressurized can. so when do i add the oil, before i use the vaccum pump, or do i remove a line after i use the pump to add the oil?
Also, it takes 8 oz of pag oil and 32 oz of r134 correct?
thanks
matt

2001NBMZ28

Lots of AC questions lately- hopefully an auto AC guy/sponsor will chime in. I do home HVAC and rarely worry about adding oil - especially if it's only low and never been opened to the atomosphere. When adding do it on the low side while adding referigerant if you have gauges. If you're just topping it off, add, no need to use a vacuum pump or add oil.

koolaid_kid

First, if you had a leak you need a new dryer. It has dessicant in it that will fill with water and stop up. They are $21 at RockAuto and usually (relatively) easy to replace. You are already in there, do it now.
Second, you need to draw a vacuum. You need a decent vacuum pump to do this; it takes 30 minutes or so. Your gauges will tell you how much vacuum you are drawing and if it is still leaking.
Third, you need to add exactly the amount of R134a that your system requires. You can't just add more like you could with R-12, it does not work the same way.
Whatever you do, DO NOT add stop leak. It may stop up your system completely and then you would have a lot of work on your hands.
Also, if you did not do it already, you need to replace as many of the o-rings as possible. The o-ring kits are cheap and will prevent having to open the system again.
Don't put any more oil in it unless you have a dry system. There is no way to know how much it needs. It is usually poured into a replaced component, so if you are dead set on adding it pour it into the dryer, perhaps half what it needs if dry.
Hope this helps.

4montecarlo

thanks for the replies
2001 i want to do more than top it off, i dont know how much freon is in the system, and i would rather know than guess.
koolaid how do i know if its a dry system? my ac system was charged up last year and this year, its out. I found the leak to be the low pressure side nozzle. I replaced it and want to recharge the system. What is the best way? i will order the dryer. How much if any oil should i add back to the system? and i think i would need the whole 32 oz of r134?
thanks
matt

koolaid_kid

First, a dry system is either a brand new one or one that has been flushed. You have neither, therefore you have oil already in the system. You have clearly opened up the system to replace the part.
When you replace the dryer (get the Delco part) pour exactly one ounce into the dryer before you install it. Be sure you use the correct PAG oil for your vehicle.
Again I suggest you replace as many o-rings as possible. The kits are readily available and not very expensive. http://www.autozone.com/autozone/par...mString=search
Assemble everything and tighten it all up. Connect your gauge set and hang it where you can see it easily whilst you work on the system. Make sure the pump has oil in it, it has a sight glass. Attach the vacuum pump to the center of your gauges where the the refrigerant usually goes. Open both the high and low side valves and turn on the pump. They are usually noisy so be prepared. It should show a vacuum rather than pressure on your gauges. Let it pull a vacuum for at least 30 minutes. Turn the pump off and let it sit for 10-15 minutes. If you have no leaks the vacuum will stay. If you have leaks it will go back to zero, so now you need to find the leak(s) and fix it(them). They are almost always the o-rings. Once the vacuum stays, you are ready to charge the system. Close both valves so the vacuum stays.
R143a systems must have exactly the specified amount of refrigerant or they will not function properly. Your system uses exactly 2 pounds as you know, use no more and no less. Adding the refrigerant is pretty straightforward.
Another thing, once the system is fully charged, the gauges will indicate whether or not there is an issue in the system by their readings. Readings that are to high or too low on either side indicate an issue, but you cannot use the gauges for this debugging until you have completed all the work above. Debugging is beyond the scope of this thread, so I will close with that.
Here are a few videos to help you along the way. Best of luck.
[autostream]http://autostream.com/camaroz28/?page_type=firebirdplayerthumbnail&framepage=1527& transactionid=1312459063-685872138&posted_by=koolaid_kid_www.camaroz28.com& youtube_video_id=F5w3lR88fqQ[/autostream]
http://www.youtube.com/watch?v=WblfmWnFPEc
http://www.youtube.com/watch?v=iNsyi...eature=related

4montecarlo

Awesome! Thats exactly what i needed to know. i should be able to work on it this weekend.
Thanks again
matt

koolaid_kid

You are welcome. Just follow my instructions to the letter, don't take any shortcuts and you will be fine.
BTW, don't tell anyone else, those are state secrets.

4montecarlo

This morning, i got the new dryer and orings. Before i put on the new parts tho, i wanted to test the vaccum pump and gauges. And of course the gauges set was broken, the low side valve wouldnt open/close. So i could have replaced the parts, but i wanted to check for any other leaks first just to kind of try out the tools i rented. During that process, i realized my compressor doesnt appear to be doing anything. I even tried to jump the low side switch, and still nothing. I tested the relay with the relay for the foglights, and still no good. Before i can do anything else, i need to make sure my compressor is working. what should i check next?
thanks
matt

4montecarlo

afte some searching, i think i need to clear my codes as i prob have code 61 and that wont allow the compressor to kick on. i will try that first.
thanks
matt

koolaid_kid

Sounds like one of those rental gauge sets; they are poor to start with. It sounds like you have a reasonable understanding of the operation of the system, which is always a good thing.

4montecarlo

i was able to work on this some yesterday, now that the temps are in the 80s, figures.
But i was able to jump the compressor by the relay, using pins 30 and 87. I vaccum the system down and added the freon i had at home, i will still need to add one more can, but its already cold.
thanks for all the help
matt