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Discussion Starter · #1 ·
Do you know what R1234 costs??...Good lord! Anyway I just have the charging kit for the low side. The condenser fan is running, the gauge is almost in the red,and the air coming out is cool at best. Speed the engine up to 2K RPM and the gauge falls back in green, and the air is cold. I shot some more freon in, but didnt seem to help.also the low side line gets cool but not cold.
 

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"what R1234 costs??" = $$
No HVAC guy here. Good luck!
 

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Overcharging an AC system is as bad as undercharging. If you have a leak, you also need to replenish compressor oil along with the freon.

What exactly do you mean "the gauge is almost in the red?" If you want to try to diagnose farther, you need to put a proper set of AC gauges on it to see if the system is overpressurized and see what kind of high side pressure is building. The do it yourself kits are fine when the problem is low freon, but there are many possible causes for poor cooling at idle, including a worn compressor that can only make good pressure at higher RPM.
 
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Discussion Starter · #4 ·
Now I have to ask..how long does a compressor typically last? I have 110K miles Hot Texas summers.
 

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The Bacon Hauler (‘12 Cop Charger)
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I had a similar issue with my 2010 Challenger - cold air turned barely cool when I needed it most (idling or stop and go), and it turned out I had overcharged the system.
 

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Now I have to ask..how long does a compressor typically last? I have 110K miles Hot Texas summers.
Any accessory is on borrowed time past 100k, but it's more likely to be an overcharge. Regardless you want that checked first. If you bought one of those jumbo cans you could easily overcharge a system that was a little low.
 

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2020 Dodge Challenger Hellraisin Scat Pack
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Now I have to ask..how long does a compressor typically last? I have 110K miles Hot Texas summers.
Have driven 4 cars to 150K+ miles and one of those to 317K miles. Never had an A/C compressor or even an A/C system problem.

Years ago my auto tech buddies told me the best thing I could do for my car's A/C system is to use it regularly. With my early cars I made it a point to in the winter months run the A/C system a while every so often.

Then in 2002 when my cars were equipped with auto climate control systems and the A/C system ran much more often and in the non summer months I mostly relied upon that usage.

The other thing I do is before I put the car away for the day I turn off the A/C compressor -- when a few minutes away from home and the garage -- and just run the cabin vent fan for a bit to "dry" the air vent tubes and the evaporator. This reduces the chance these surfaces which are damp provide a suitable environment for mold/mildew to take hold.

Oh, and change the cabin air filter on schedule.
 

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Have driven 4 cars to 150K+ miles and one of those to 317K miles. Never had an A/C compressor or even an A/C system problem.

Years ago my auto tech buddies told me the best thing I could do for my car's A/C system is to use it regularly. With my early cars I made it a point to in the winter months run the A/C system a while every so often.

Then in 2002 when my cars were equipped with auto climate control systems and the A/C system ran much more often and in the non summer months I mostly relied upon that usage.

The other thing I do is before I put the car away for the day I turn off the A/C compressor -- when a few minutes away from home and the garage -- and just run the cabin vent fan for a bit to "dry" the air vent tubes and the evaporator. This reduces the chance these surfaces which are damp provide a suitable environment for mold/mildew to take hold.

Oh, and change the cabin air filter on schedule.
Your buddies gave you good advice and I'll echo everything you said there. Speaking as a longtime mechanic who was the shop A/C guy, I can confirm that regular use is key to maximizing seal life. The compressor oil that circulates with the refrigerant also keeps seals healthy, especially seals on compressor internals but to a lesser extent all the seals in the system.

A lot of people also don't realize that ALL A/C systems leak refrigerant, although modern systems are better. The molecules are so small that it's impossible to create perfect seals on moving parts. Add to that, the R-134a molecule is a lot smaller than the R-12 used in cars for decades, so even with modern seal technology slow leaks are just a fact of life. It might take 6 or 8 years to need a recharge, but the time always comes and doesn't automatically mean there are repairable leaks. In this case the system doesn't use oil, so you don't want to recharge with refrigerant that has oil added (which is how most of the home-repair products are made).

Oil leaks out along with the refrigerant, which often requires oil to be added with a top-off, but too much oil can cause issues just like too much refrigerant. The two refrigerants also use oils that are incompatible and will turn into mud and trash the whole system if mixed. Used to see that a lot back in the 90s when R-134a was still a new thing and people were trying to do backyard retrofits.

The bottom line is that A/C systems are fundamentally simple, but there are finer points to their operation and special equipment required to work on them properly that make home repairs a tall order. We used to pay around $700 for a good A/C vacuum pump back in the 90s. Not sure what they go for now but I'm betting they haven't gotten any cheaper.
 
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Have driven 4 cars to 150K+ miles and one of those to 317K miles. Never had an A/C compressor or even an A/C system problem.

Years ago my auto tech buddies told me the best thing I could do for my car's A/C system is to use it regularly. With my early cars I made it a point to in the winter months run the A/C system a while every so often.

Then in 2002 when my cars were equipped with auto climate control systems and the A/C system ran much more often and in the non summer months I mostly relied upon that usage.

The other thing I do is before I put the car away for the day I turn off the A/C compressor -- when a few minutes away from home and the garage -- and just run the cabin vent fan for a bit to "dry" the air vent tubes and the evaporator. This reduces the chance these surfaces which are damp provide a suitable environment for mold/mildew to take hold.

Oh, and change the cabin air filter on schedule.
I do the same thing. It also allows pressures to drop.

Your buddies gave you good advice and I'll echo everything you said there. Speaking as a longtime mechanic who was the shop A/C guy, I can confirm that regular use is key to maximizing seal life. The compressor oil that circulates with the refrigerant also keeps seals healthy, especially seals on compressor internals but to a lesser extent all the seals in the system.

A lot of people also don't realize that ALL A/C systems leak refrigerant, although modern systems are better. The molecules are so small that it's impossible to create perfect seals on moving parts. Add to that, the R-134a molecule is a lot smaller than the R-12 used in cars for decades, so even with modern seal technology slow leaks are just a fact of life. It might take 6 or 8 years to need a recharge, but the time always comes and doesn't automatically mean there are repairable leaks. In this case the system doesn't use oil, so you don't want to recharge with refrigerant that has oil added (which is how most of the home-repair products are made).

Oil leaks out along with the refrigerant, which often requires oil to be added with a top-off, but too much oil can cause issues just like too much refrigerant. The two refrigerants also use oils that are incompatible and will turn into mud and trash the whole system if mixed. Used to see that a lot back in the 90s when R-134a was still a new thing and people were trying to do backyard retrofits.

The bottom line is that A/C systems are fundamentally simple, but there are finer points to their operation and special equipment required to work on them properly that make home repairs a tall order. We used to pay around $700 for a good A/C vacuum pump back in the 90s. Not sure what they go for now but I'm betting they haven't gotten any cheaper.
" It might take 6 or 8 years to need a recharge"
Guess I've been lucky. The A/C systems in both my 20 year old Firehawks work perfectly and have never been touched. I do make a point of running them every time I take the cars out.
In your opinion, would it be a good idea to be proactive and have therm checked/charged this Summer. This is the year I'm doing their 5 year PM.
 
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I am not sure that it is even possible to get just a vacuum pump with the dedicated R1234yf connector. In the dealership that I work in, we use a self contained R1234yf machine that evacuates the refrigerant after testing for purity, vacuums the system, leak tests it and only if it passes will it recharge the system. I probably could adapt some R1234yf connectors to my old, no longer used R12 gauge set, but since the machine is available I just use it. It does seem like the A/C systems nowadays are much better at holding the charge than the old ones, most of the time when I get into a low charge problem I find a damaged condenser.
 

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I am not sure that it is even possible to get just a vacuum pump with the dedicated R1234yf connector. In the dealership that I work in, we use a self contained R1234yf machine that evacuates the refrigerant after testing for purity, vacuums the system, leak tests it and only if it passes will it recharge the system. I probably could adapt some R1234yf connectors to my old, no longer used R12 gauge set, but since the machine is available I just use it. It does seem like the A/C systems nowadays are much better at holding the charge than the old ones, most of the time when I get into a low charge problem I find a damaged condenser.
I'm sure the tech has come quite a ways. When I was turning wrenches we were still using vacuum pumps on the center leg of our gages to pull vacuum on everything.

Bought a couple Snap On A/C machines that had them internally but still used the old gages and pumps as a backup for pulling vacuum on multiple cars at once during the busy season.

I still have my adapers from the R12 system threads on the gages to R134a quick connects.

" It might take 6 or 8 years to need a recharge"
Guess I've been lucky. The A/C systems in both my 20 year old Firehawks work perfectly and have never been touched. I do make a point of running them every time I take the cars out.
In your opinion, would it be a good idea to be proactive and have therm checked/charged this Summer. This is the year I'm doing their 5 year PM.
If the air blows cold on a hot day, there's no reason to service anything.

Also bear in mind your Hawks dont sit outside through the seasons so the seals don't take the same kind of thermal cycle beatings as the average car. They would be R-134a from the factory, which means they have synthetic seals, which are a lot better than the old rubber seals that were used with R12.
 

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If the air blows cold on a hot day, there's no reason to service anything.

Also bear in mind your Hawks dont sit outside through the seasons so the seals don't take the same kind of thermal cycle beatings as the average car. They would be R-134a from the factory, which means they have synthetic seals, which are a lot better than the old rubber seals that were used with R12.
Appreciate the input.
Thanks much. (y)
 

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We still have a vacuum pump that connects to the center hose on a gauge set, but it has been at least 20 years since I used it. It has been at least ten years since my R12 gauges have been used, since the machines have built in gauges I have gotten used to using the machines instead of separate gauge sets.
 

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We still have a vacuum pump that connects to the center hose on a gauge set, but it has been at least 20 years since I used it. It has been at least ten years since my R12 gauges have been used, since the machines have built in gauges I have gotten used to using the machines instead of separate gauge sets.
Sounds about right. I stopped wrenching in 2002 and moved on to fabrication. Back then the machines were still pretty new and cost a ton of money.
 
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