samuelcosmo76

Summere is here, so I decided to get my air working the other day.

I vented out the remaining R12, and filled it up with an oil charge, and 4 cans of R134. It blew ICE COLD for about 30 minutes, and then stopped. I changed the expansion valve....still no dice. Then the next day it was cold again, and its been on and off like that since.

Any ideas? I know i didn't vacuum out the air and everything, but I'm trying to do it on the cheap.

thanks guys! :-)

sweeperking

Are you using gauges? What are your high and low pressure reading? Did you replace the reciever/dryer?

samuelcosmo76

No gauges. I was trying to avoid spending the money on them. I didn't replace the dryer, only the expansion valve. The compressor kicks in, and I see freon in the sight glass for a few minutes, then it bubbles up and disappears.

I know its hard to diagnose without the gauges :-/

sweeperking

First off I bet your freezing up at your expansion valve but wont really know for sure unless you use gauges. If you want it to work, replace your reciever dryer, vacate the system for a minimum of 30 mins (longer time if ambiant temp is below 72f) install the refer thru a manifold gauge set. One more thing here, air conditioning isnt something to be messing with if you dont know what your doing. YOur dealing with high pressures that can be dangerous, if your not sure about this bring it to some one that knows.

samuelcosmo76

Hey guys here's an update. I got gauges on the system, and the compressor wasn't making any pressure, so i replaced it, along with the drier. Now when i vacuum it and fill it up, i get pressure on the high side and nothing on the low side. I think i have a clog somewhere in the system? I tried blowing out the evaporator with air, but it didn't do any good. Any ideas what i should try next?

thanks guys!

sweeperking

I now you said you replaced it but because you ran the system with the old dryer and didnt vacate it before I still say its yor expansion valve. Indication of an expansion valve stuck shut is the high side reading low pressure and the low side reading very low to negative pressure. You might get away with dissassembly and cleaning it, good luck though.

samuelcosmo76

Alright i'll give that a shot. how do i clean the valve? thanks for the tip.

1966sportfury

134a wont work in a r12 system unless you replace the hoses, i was gonna refill my r12 system with 134 and a mechanic told me the r12 hoses leak the 134 a off fast?

samuelcosmo76

I never heard that one, but I'll look into it.

1966sportfury

they called it retro fitting.

mopardrt

i need new revalves for my dart A/C anyone know where to find two?

sweeperking

Not true, I have done many conversions to include my own. A long time ago when 134a first hit the market there were compatibility issue with the compressor oils but even back then if you did a good flush of the lines and use a ester oil that would work just fine. Today you can use ester or pag oil in a 134a converted from r12 all you need to do is replace the reciever dryer and vacate the system before you refill it. Also, you can no longer go by the label when installing the 134a. What I mean is if the underhood label says (for example) 2lbs 4oz of r12 well now you would only put in about 2lbs. Your gage pressures will also be differn't. There is a conversion but I dont have it handy the best way to install 134a is by checking register temp.

sweeperking

Do you mean compressor reed valves?

sweeperking

Sorry dude, almost forgot about you. Check one more thing before you remove the expansion valve. Your expansion valve will have either one or two capilliary (sensing lines) these are maybe 1/8" copper lines, maybe 8-12" long depending on your application. Anywho, these lines or line are very fragile you have to be carefull handleing them. The end of one of the copper lines in inserted into a pocket in the low side/suction line and if you have a second line it should have a brass fitting end that threads on to the same line. Check the line that is inserted in that pocket it should go in at least 3" if not you have to clean that pocket this is how the expansion valve senses line pressure/temperature. If I totally confused you dont worry this is hard to put into words just let me know and I will try and reword it>

1966sportfury

sweet i was always told no it wont work, they just wanted $$ im sure, i did try it still.. with no luck =+(

mopardrt

I guess lol I thought it was revalves hahha see how much I know about A/C's

samuelcosmo76

wow i forget about this thread....

so yeah, i ended up replacing the compressor, and found there was still a clog in the line, so i blew all the components out with an air compressor.

it works great, but now my lines are starting to develop bubbles......that's for next summer. haha