I think I just blew up my A/C

[tony-muscle]

Today I went for a high performance drive during lunch break. It was hot out so I had the A/C on. While accelerating down the highway at some point I lost A/C. A few miles down it started to feel hot inside and could hear a noise from the hood. The noise went away after I turned the A/C off so definitely something was wrong. I just had accelerated to about 6,500 rpms so I had the feeling that I had overrevved the compressor. I guess I didn't think about it before. Before I had only gone to about 6,300 rpms. Once I got home I could see the mess. Oil everywhere, the high pressure hose burst, and the compression nut of the low pressure fitting was completely off. I believe that the system over pressurized and broke. The fact that the coupling nut of the fitting was off makes me think the pressure went pretty high. It was not that it unscrewed itself because that should have released the pressure and should not have caused the hose to burst. The coupling nut is aluminum so I assume that enough pressure expanded it to push it past the threads. I feel dumb now for not having thought about the RPMs of the compressor. My compressor is a York and now reading the spec it says 6,000 rpm  :shootself:  . On top of that I probably had overfilled the system with refrigerant. My question now, do you think the compressor is done? Am I looking at a new compressor besides the hose? What else should I be worried about? Maybe it is time to upgrade to a whole new system from Classic Auto Air or similar? Can one of these be revved up to 6,500 rpm?

These pictures shows the burst hose. I had already screwed the low pressure fitting nut back in. As you can see the burst is coincidentally very close to the steering fluid radiator. This radiator is attached to the compressor so there shouldn't be independent movement between them, but I wonder if the hose could have moved and touched the radiator and caused it to burst, but unlikely due to how close it was to the fitting. Also, it could simply be that it was the hottest spot on the hose.

 

[73pony]

The power steering cooler does not get that hot. That is a pressure burst. Looks like that just happen to be the weakest spot on your hose. My guess would be as you stated. The high RPM over pressurized the system, especially if you think it as over charged. As for eh compressor only way to know is to test it out, my guess is it is fine since the hose blew and not the seals on the compressor. You could increase the diameter of compressor pulley or reduce the size of the crank pulley to reduce the RPM at the compressor going forward. Or just make sure to turn the AC off when you are making high RPM runs. Hope this helps. Sorry to hear about the blow up.

 

[Jeff73Mach1]

I would convert to a sanden compressor and a modern condensor that has larger diameter tubes in it. The sanden can spin at higher RPM without difficulty and is built for modern refrigerants

 

[Carolina_Mountain_Mustangs]

Now you know why they did not put any lower gear in the rear than 3.25 with AC.

One of the first things I did when I got my car new was to take the AC belt off, lol.

Would be difficult to change pulley size on the compressor since it is the clutch. I am sure a newer model compressor would be better just will not look correct. But unless you are trying to be perfect doesn't matter.

I was in Charlotte last weekend and in high 90's did not have air and did not really bother me. It is not a dry heat here with all the humidity either.

Don't know that you need to change the whole system just the compressor and hoses maybe.

 

[tony-muscle]

I would convert to a sanden compressor and a modern condensor that has larger diameter tubes in it.  The sanden can spin at higher RPM without difficulty and is built for modern refrigerants

Thanks. I am leaning toward a whole new system from Classic Auto Air: https://www.classicautoair.com/shop/1971-ford-mustang-air-conditioning-system/

It will be a bit more expensive but everything will be new. However, I am not looking forward to disassembling the whole interior to install the evaporator.

 

[jowens1126]

that classic auto air system is great. I love the video from autoediits. I like the electronic valves instead of vacuum controlled.

 

[donkost]

I believe the rev limiter for the 429 SCJ was at 6150 rpm's, and AC was not offered for those cars. I know you don't have the 429 SCJ but it tells you they did not want to have the AC compressor running at that rpm level. I think the rev limiter would have been set at 5800 rpm's for my 429 CJ. I never shift anywhere near there. My Ferrari has a 7700 rpm redline but even in that car I shift at around 5000 rpm's at the highest normally. That car still has nice cold R-12 AC in it.

 

[Canted 393]

Here is a kit were you use your orginal evaporator, I used their kits and have been happy with them.

https://originalair.com/71-73-ford-mustang-engine-compartment-upgrade-v-8-134a-w-adapter-brackets

 

[Jeff73Mach1]

You don't have to disassemble much if you will pull the glove box, the dash cap and the passenger seat everything else can accessed without much difficulty. You will need to take apart the center stack, but that is easy

 

[B229218]

You CANNOT use r134 with older compressors, they are not rated for higher pressure that the newer freon requires. I went through same issue years back on 1977 460/york style r134 combo. put a sanden unit on or spend$$$ and convert back to r12.

 

[B229218]

Today I went for a high performance drive during lunch break. It was hot out so I had the A/C on. While accelerating down the highway at some point I lost A/C. A few miles down it started to feel hot inside and could hear a noise from the hood. The noise went away after I turned the A/C off so definitely something was wrong. I just had accelerated to about 6,500 rpms so I had the feeling that I had overrevved the compressor. I guess I didn't think about it before. Before I had only gone to about 6,300 rpms. Once I got home I could see the mess. Oil everywhere, the high pressure hose burst, and the compression nut of the low pressure fitting was completely off. I believe that the system over pressurized and broke. The fact that the coupling nut of the fitting was off makes me think the pressure went pretty high. It was not that it unscrewed itself because that should have released the pressure and should not have caused the hose to burst. The coupling nut is aluminum so I assume that enough pressure expanded it to push it past the threads. I feel dumb now for not having thought about the RPMs of the compressor. My compressor is a York and now reading the spec it says 6,000 rpm  :shootself:  . On top of that I probably had overfilled the system with refrigerant. My question now, do you think the compressor is done? Am I looking at a new compressor besides the hose? What else should I be worried about? Maybe it is time to upgrade to a whole new system from Classic Auto Air or similar? Can one of these be revved up to 6,500 rpm?

These pictures shows the burst hose. I had already screwed the low pressure fitting nut back in. As you can see the burst is coincidentally very close to the steering fluid radiator. This radiator is attached to the compressor so there shouldn't be independent movement between them, but I wonder if the hose could have moved and touched the radiator and caused it to burst, but unlikely due to how close it was to the fitting. Also, it could simply be that it was the hottest spot on the hose.

what is copper steel wool coming from fitting :huh:

 

[tony-muscle]

what is copper steel wool coming from fitting :huh:

I dont think so but i can look at it more carefully once I am back. It may be the reinforcement of the hose.

Sent from my SAMSUNG-SM-G930A using Tapatalk

 

[tony-muscle]

You CANNOT use r134 with older compressors, they are not rated for higher pressure that the newer freon requires. I went through same issue years back on 1977 460/york style r134 combo. put a sanden unit on or spend$$$ and convert back to r12.

This is a newer York compressor for R134
Sent from my SAMSUNG-SM-G930A using Tapatalk

 

[tony-muscle]

that classic auto air system is great. I love the video from autoediits. I like the electronic valves instead of vacuum controlled.

Does this system gets fresh air from the outside or not? I see there is a block off plate.

Sent from my SAMSUNG-SM-G930A using Tapatalk

 

[7173Vert]

You CANNOT use r134 with older compressors, they are not rated for higher pressure that the newer freon requires. I went through same issue years back on 1977 460/york style r134 combo. put a sanden unit on or spend$$$ and convert back to r12.

Hmmm. That's not what i have heard or seen...

 

[B229218]

You CAN use r134 with older compressors,however  they are not rated for higher pressure that the newer freon requires. I went through same issue years back on 1977 460/york style r134 combo. put a sanden unit on or spend$$$ and convert back to r12. The old piston works, eat. do not like higher head pressures for long. That is what blew my converted system out back in 2004. ur results may vary of course.

Hmmm. That's not what i have heard or seen...

Well, from what I have read/been told by a/c  mechanics/installers, as well from outfits like old air products, ect., is the old compressors use  pistons, the newer sanderns rotary. rotary is better suited for rpm, and is designed for higher head pressure. R 132 is not as efficient a heat exchanger as R 12 was, consequentially R 132 requires 20-30% higher system pressure to operate well, this is where piston compressors start to fail, esp. when it is very hotter outside.

 

[tony-muscle]

You don't have to disassemble much if you will pull the glove box, the dash cap and the passenger seat everything else can accessed without much difficulty. You will need to take apart the center stack, but that is easy

Does the A/C kit come with a heater core or do you reuse the current? If reusing I guess it is a good time to get a new one just in case.
Sent from my SAMSUNG-SM-G930A using Tapatalk

 

[Jeff73Mach1]

The one I have used and the one I am installing on a 56 Ford F 100 both utilize their own heater core built into the unit. https://www.oldairproducts.com/

Currently about 2/3 of the way through the install. The hoses have to be cut to length and crimped and I have a little more wiring and duct work to complete. Nice unit with all electric controls.

 

[tony-muscle]

The one I have used and the one I am installing on a 56 Ford F 100 both utilize their own heater core built into the unit. https://www.oldairproducts.com/

Currently about 2/3 of the way through the install. The hoses have to be cut to length and crimped and I have a little more wiring and duct work to complete. Nice unit with all electric controls.

For the one in the Mustang, do you have to remove the old ducts in lieu of the flexible ducts in the kit?Also, i see there is a plate to seal the cowl intake opening. So where does it take the fresh air from? Or it doesnt?

Sent from my SAMSUNG-SM-G930A using Tapatalk