71 Mustang Mach1 Fastback AC help

JJHstang · Sep 23, 2018

I am looking for advice. My 71 Mach 1 with 351W 4V (not original engine). I was told had AC (original Ford compressor) but when I got it the AC only blew air, not even cool air.
I took it to mechanic, not an AC mechanic. I asked to have it converted to R134. I should have investigated more. All the mechanic did was test for leaks and told me the system was empty but also found no leaks. He only replaced the 2 adaptors and with the AC turned off filled the system with R134. He told me when they turned on the AC oil blew out the clutch.
Now wondering what to do. I do know I need to take to an authorized AC shop. I don't need it to blow cold air but would like cool air.
Should I have the adaptors replaced back to original R12 and see if the clutch blow out can be fixed or spend the money and have the whole system replaced vintage air system?

JJHstang · Sep 24, 2018

I am new to the forum and wondering if I am not posting questions correctly. I see I am getting reviews but know replys with .suggestions

Onetim · Sep 26, 2018

Hi new here as well, things are kind of quiet, not sure why. Keep it original, if staying with 134A the system needs to be flushed of the old oil, new receiver dryer, some would do new o rings, and for sure a new compressor seal, PAG oil, and a 134A fill and you should be good. All regular AC shop work.

JJHstang · Sep 26, 2018

Onetim said:
Hi new here as well, things are kind of quiet, not sure why. Keep it original, if staying with 134A the system needs to be flushed of the old oil, new receiver dryer, some would do new o rings, and for sure a new compressor seal, PAG oil, and a 134A fill and you should be good. All regular AC shop work.

JJHstang · Sep 26, 2018

Thank you. What do you think about the evaporator. I get mixed messages. Some say it needs to be replaced. Others say it should be ok if you just want cool air. Do you know of a way to check to see if air is flowing through it.

Onetim · Sep 27, 2018

Your evaporator will be just fine as long as it does not leak, you will get cold air. You would get a bigger gain by tinting the big flat back window.

JJHstang · Sep 27, 2018

Thanks, I think I will take it to a recommended AC shop. I am going to have him remove the R134 adaptor fittings, put on R19 adaptors. Test for leaks which pretty sure if oil came out the clutch there is a leak. If the only leak get a cost to repair if it can be and go from there.

JJHstang · Sep 29, 2018

Onetim said:
Hi new here as well, things are kind of quiet, not sure why. Keep it original, if staying with 134A the system needs to be flushed of the old oil, new receiver dryer, some would do new o rings, and for sure a new compressor seal, PAG oil, and a 134A fill and you should be good. All regular AC shop work

Onetim said:

Your evaporator will be just fine as long as it does not leak, you will get cold air. You would get a bigger gain by tinting the big flat back window.

Click to expand...

Maybe you have an idea what the attached picture is. I posted before but like my other posts a lot of views but no replies. I feel it is to get air to feet area but it is not connected to anything. It is under the dash behind the radio and tubing comes out on the driver and passenger sides. Hard to explain it. The approx 2" tubes just get larger as the in the center to 5 to 6" high, open at the top(measurements are a guess). It is all one moulded piece. Both ends of the tubing have the same rough cut out near the ends. The cut outs do not look professionally made. The picture is on the passenger side.

WORTH · Oct 3, 2018

Couple of things, if you don't have a GOOD AC shop look at it you will probably have issues. I owned an AC shop for 20 years, if your seal is leaking that is an easy repair for an AC guy. He'll have to replace the seal, flush the system, replace the receiver dryer and the AC oil and charge the system, and at that point he will figure out if you have other issues. Unfortunately you can't diagnose an AC system that isn't working. I would go with a shop that will do it with R134. Although R12 is a better freon, it's way too expensive these days, and I've had real good luck with the R134 over the years.

JJHstang · Oct 3, 2018

WORTH said:
Couple of things, if you don't have a GOOD AC shop look at it you will probably have issues. I owned an AC shop for 20 years, if your seal is leaking that is an easy repair for an AC guy. He'll have to replace the seal, flush the system, replace the receiver dryer and the AC oil and charge the system, and at that point he will figure out if you have other issues. Unfortunately you can't diagnose an AC system that isn't working. I would go with a shop that will do it with R134. Although R12 is a better freon, it's way too expensive these days, and I've had real good luck with the R134 over the years.

I appreciate the response from someone with experience. I have questions based on different things I have read and watched on YouTube. The first time when I thought of converting to R134 online the guy just had the system flushed , checked for leaks, changed out the adaptors, started the car and the AC, started filling with new R134. Now I have read that you need to change the oil in the compressor, change the condensor, different hoses, receiver drier. What is right?

JJHstang · Oct 3, 2018

JJHstang said:
I appreciate the response from someone with experience. I have questions based on different things I have read and watched on YouTube. The first time when I thought of converting to R134 online the guy just had the system flushed , checked for leaks, changed out the adaptors, started the car and the AC, started filling with new R134. Now I have read that you need to change the oil in the compressor, change the condensor, different hoses, receiver drier. What is right?

Sorry you mentioned everything I asked again except the hoses and condensor being replaced. Sorry to ask what you already told me.

WORTH · Oct 5, 2018

I had my shop when they phased out R-12 and forced the R134 on us. There was a load of mis-information about what you needed and what was suppose to happen. It was expensive to do it "the right way", so if you owned a beater and just wanted a little cold for the summer we would just suck out the R-12 that was left in the system, replace the reciever or accumulator if it was a GM, ad a little pag oil to the fill port, give it a good long evacuation, and charge it with 134A. And I never remember having an issue with any of those cars despite the doom and gloom that was suppose to happen.

I would however stay away from the miracle freons and stick with R134.

JJHstang · Oct 5, 2018

Worth: Thanks again. If as I mentioned in my first post. "I took it to mechanic, not an AC mechanic. I asked to have it converted to R134. I should have investigated more. All the mechanic did was test for leaks and told me the system was empty but also found no leaks. He only replaced the 2 adaptors and with the AC turned off filled the system with R134. He told me when they turned on the AC oil blew out the clutch."
If they found no leaks why then when they filled and turned on th AC oil blew out the clutch?
I have a few thoughts. They put in to much R134, based the lbs on R12 and from what I have read you can't put in as much R134. They filled it with R134 then turned on the AC and I read you should have the car running with AC on while filling thd system.
You being an expert what thoughts on it do you have?

WORTH · Oct 6, 2018

More than likely, the guy that did it just didn't have a clue. That said, when we were using R12, there were a few very good leak detectors on the market, the one we used at my shop I believe was a A10 GE unit. It was so sensitive you could accidently pick up a leak from the car in the bay next to you. You could fine tune it and pinpoint a leak anywhere in your system.

However after they went to R134A, I never found a detector that was worth a . We ended up relying on charging the system with die and searching with a light to find leaks which is very inefficient in a car where you just can't focus the light on every part of the AC system. The only thing I could tell you for sure on a 134 system is if I evacuate the system and it wont hold a vacuum, IT DOES HAVE A LEAK, however I can't always find that leak, and if I do find "A" leak, it may not be the only one.

A good example is my own 2005 Grand Marque, it sat for most of it's life in my father inlaws driveway, I bought it in 2015 with 10,000 miles on it, it had a few lack of use issues, one being the compressor seal let go as soon as I started using the car. It was a large leak, I could hear it pissing out. At that point there is NO WAY I could determine if it had any other issues so the only thing I could do is replace the accumulator and the o-tube and the compressor and charge the system. Since then I haven't been able to find another leak, but I have had to put in a little 134 every summer since. It's just the nature of the beast, the good thing is 134 is cheap.

As far as what I am going to do with my current resto project, a 1966 F-100, it will get 134A.

JJHstang · Oct 23, 2018

Thanks

JJHstang · Mar 9, 2019

For all those that replied, thank you. I have taken it to a highly rated AC shop, not a chain. Since the engine is not original and the compressor clutch is leaking and other parts I was told should be replaced I have decided to have a Vintage air system installed. He also mentioned the original York compressor in 71 was not all that good.
Does anyone think I can sell some of the be removed parts, such as the compressor?

71 Mustang Mach1 Fastback AC help

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