Questions on 81 ac
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Instructor
Joined: May 2013
Posts: 167
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Questions on 81 ac
Where is the orifice tube located?
Do the blower fans in these cars blow out very hard on high? Mine seems to work on all speeds, but feels like low is almost nonexistent and high isn’t real great. Just wondered if I should replace the fan.
Plan on changing out out the dryer and pulling it down with a vacuum and converting it to 134. I’ve done it before with good results but just can’t remember what all I had to do. From what I’ve been reading all you really should do is change to orifice tube and dryer, pull vacuum on the system and refill with Freon with oil
Do the blower fans in these cars blow out very hard on high? Mine seems to work on all speeds, but feels like low is almost nonexistent and high isn’t real great. Just wondered if I should replace the fan.
Plan on changing out out the dryer and pulling it down with a vacuum and converting it to 134. I’ve done it before with good results but just can’t remember what all I had to do. From what I’ve been reading all you really should do is change to orifice tube and dryer, pull vacuum on the system and refill with Freon with oil
Melting Slicks
Joined: Feb 2017
Posts: 3,232
Likes: 1,232
From: PHX AZ
Not quite....F-12 oil is different the CFC-134A oil.....PAG oil vs Ester. So what you have to do is REMOVE and flush all the old oil out of everything. You can remove the compressor and drain it. You can flush (i used denatured alcohol) the condensor and evaporator...just flex rubber lines and compressed air and a siphon gun.
Then I blew out everything until DRY. {lines and EVERYTHING!}
You are replacing the receiver dryer, so that's great.
If you do not do this the two oils which are NOT compatible will make a amalgamy-gooey mess and won't lubricate, nor will it flow through the orifice tubes etc.
You then have to replace with CFC-134A oil per volume of lbs.
You should pour the oil into the compressor and roll it about...don't want to flood it nor start up dry.
New dryer
Vacuum to 28" for at least an hour...depends on humidity on that day.
Then you have to remake the fittings for CFC-134A.
You are correct in assuming the CFC134A is as good as Freon F-12.....The'internet says no' but that is an internet myth.
MY Converted Car here in AZ at 100°F produces 29°F AT THE DUCT.....most F-12's are at 40°...so there's another myth shot to heck!
Now I'm an HVAC engineer and I was very **** in what I was doing, and was very careful in sealing the condensor core so the twin fans would pull across it. My car runs at 165 or so.
good luck SIR!
unkahal.
Then I blew out everything until DRY. {lines and EVERYTHING!}
You are replacing the receiver dryer, so that's great.
If you do not do this the two oils which are NOT compatible will make a amalgamy-gooey mess and won't lubricate, nor will it flow through the orifice tubes etc.
You then have to replace with CFC-134A oil per volume of lbs.
You should pour the oil into the compressor and roll it about...don't want to flood it nor start up dry.
New dryer
Vacuum to 28" for at least an hour...depends on humidity on that day.
Then you have to remake the fittings for CFC-134A.
You are correct in assuming the CFC134A is as good as Freon F-12.....The'internet says no' but that is an internet myth.
MY Converted Car here in AZ at 100°F produces 29°F AT THE DUCT.....most F-12's are at 40°...so there's another myth shot to heck!
Now I'm an HVAC engineer and I was very **** in what I was doing, and was very careful in sealing the condensor core so the twin fans would pull across it. My car runs at 165 or so.
good luck SIR!
unkahal.
Thread Starter
Instructor
Joined: May 2013
Posts: 167
Likes: 3
L-46man
thank you so much for the information.
Ive never drained a compressor. Is there a drain plug on it or does it just drain where you disconnect the lines?
and you just put a little denatured alcohol in the lines and put some compressed air to it and it blew it all out?
could you tell me a little more on how you did that?
is it worth replacing the blower motor for a newer one for better air movement?
thank you so much for the information.
Ive never drained a compressor. Is there a drain plug on it or does it just drain where you disconnect the lines?
and you just put a little denatured alcohol in the lines and put some compressed air to it and it blew it all out?
could you tell me a little more on how you did that?
is it worth replacing the blower motor for a newer one for better air movement?
