gm and ford used to leak a lot, ford at fittings years back japanese leaked a lot less.
Do AC systems need to be topped off occasionally?
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I had to add refrigerant on my 06 Mazda3 about 3 years ago. So far it's still works as it should. It's never been ice cold, weak AC is a known "feature" of the first gens.
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I'll add my 2 cents. My wife's 1997 Honda civic that we owned since new I've only ever added r134a once in 22 years of ownership. AC is ice cold.
1998 Sienna with rear AC. Rear pipe broke and system was never as good.eventually went to a block setup on the rear section. AC never worked quite as well and needed top ups every year at the end . Dumped the van In 2015.
Went with a Dodge caravan within only front AC (NO REAR AC). Set up is simpler, less piping to fail since it's all in the engine bay.
IMO the more simpler the design of he more reliable it is when it comes to AC longevity.
1998 Sienna with rear AC. Rear pipe broke and system was never as good.eventually went to a block setup on the rear section. AC never worked quite as well and needed top ups every year at the end . Dumped the van In 2015.
Went with a Dodge caravan within only front AC (NO REAR AC). Set up is simpler, less piping to fail since it's all in the engine bay.
IMO the more simpler the design of he more reliable it is when it comes to AC longevity.
Some car AC systems seem to blow cold forever while others don't.
Yes, some leak a little.
I can see no harm in adding a little gas until the air blows cold again.
I've done this now and then with a few cars with no problems.
Avoid stop leak products since they probably won't really work and will only cause grief to a shop you end up taking the car to if you want a real repair.
Yes, some leak a little.
I can see no harm in adding a little gas until the air blows cold again.
I've done this now and then with a few cars with no problems.
Avoid stop leak products since they probably won't really work and will only cause grief to a shop you end up taking the car to if you want a real repair.
I had a 1999 Sienna and after 5 years, the AC "faded" and needed a 3oz charge. 4 years after that, the AC suddenly stopped working. The compressor was shot. I currently have a 2007 Sienna. After 6 years, it needed a charge. I had someone else do the work because it was already in for tires and an alignment. It was recharged and still works fine. My wife's Mazda6 AC started to fade after 8 years. It took about 2-3oz and is still working great. My 2000 Camry went 5 years and needed 3-4oz and another couple ounces 4 years later. I had a 1981 Toyota Corona that needed a couple oz every 2 years. After 12 years, the compressor blew. My 2011 Tacoma needed a shot of juice after it hit 40,000 miles (about 3 years). Haven't touched it since. I had a 1989 Voyager. After the first 3 years it needed 3-4oz every year. After 6 years, the compressor seals blew (A year after that, the whole engine blew).
All these cars were purchased new and driven for at lease 150k miles (some way more than that).
I guess some cars/people are lucky and some are not.
All these cars were purchased new and driven for at lease 150k miles (some way more than that).
I guess some cars/people are lucky and some are not.
Originally Posted by mk378
Don't "top off", use a machine to pull it all out (and measure how much came out, to confirm the theory that some has leaked out over the years) then recharge with the specified amount by weight. This is the only way to be sure the charge is correct.
Only way to do it. Some shops that check A/C systems for free will only throw gauges on the high and low side and say it's good when the pressures are within spec. They were wrong when I paid a shop to check the A/C and it lost half its charge (on vehicles that are 10+ years old.)
Don't "top off", use a machine to pull it all out (and measure how much came out, to confirm the theory that some has leaked out over the years) then recharge with the specified amount by weight. This is the only way to be sure the charge is correct.
Only way to do it. Some shops that check A/C systems for free will only throw gauges on the high and low side and say it's good when the pressures are within spec. They were wrong when I paid a shop to check the A/C and it lost half its charge (on vehicles that are 10+ years old.)
It is a absolute fact that in automotive AC systems it is "typical" since they are NOT sealed to have between .25 and .75 oz of R134a escape per year in a
CORRECTLY DESIGNED system which is not faulty. The molecules of this refrigerant are so small that they can and do escape though the seals over time.
The trick when topping up is how to guess how much has escaped over time. I know from personal experience that if you know the baseline for the vent temps on the system when it was working with the correct refrigerant and low pressure you can top up almost spot on. Also plenty of other "hints" from the cold suction line being cold, to the sight glass showing clear, yes many r134a systems did have sight glass installed and they are a rough guide to a system being low or filled.
The best advice I can give is add a LITTLE (just an ounce or two at a time, then check vent temp, and cold suction line, if no change after a minute add another oz or two, check again after one minute or so... if you see gradual improvement in vent temp you are on the right track. USUALLY the lowest vent temp you will see on a 85-90 F day is about 40-45 F on a decently operating system. If you are at those temps STOP adding refrigerant and be happy.
CORRECTLY DESIGNED system which is not faulty. The molecules of this refrigerant are so small that they can and do escape though the seals over time.
The trick when topping up is how to guess how much has escaped over time. I know from personal experience that if you know the baseline for the vent temps on the system when it was working with the correct refrigerant and low pressure you can top up almost spot on. Also plenty of other "hints" from the cold suction line being cold, to the sight glass showing clear, yes many r134a systems did have sight glass installed and they are a rough guide to a system being low or filled.
The best advice I can give is add a LITTLE (just an ounce or two at a time, then check vent temp, and cold suction line, if no change after a minute add another oz or two, check again after one minute or so... if you see gradual improvement in vent temp you are on the right track. USUALLY the lowest vent temp you will see on a 85-90 F day is about 40-45 F on a decently operating system. If you are at those temps STOP adding refrigerant and be happy.
Lots of good information in this thread. Interestingly enough, I topped off the R-134 in my mom's 2008 Explorer. It was purchased in Nov. 2007 new and the AC system has never been recharged. It was working until the truck was parked for about a year when the brakes became an issue. Oddly enough, when I fixed the brakes, the transmission on the Focus started slipping and the Explorer went back into service. This summer, the AC was not blowing cold at all. I have a two gauge set up that I bought from HF a few years ago and 3 cans left from the dozen I purchased from Amazon. When I connected the gauge set, the pressures were 30# on the low side and 125# on the high side. So after 12 years, it still had some pressure in the system. I looked up the acceptable pressure ranges for the ambient temp of 81 degrees and recharged the system. It took all of 3 - 12oz cans. When I was done, the measured temperature out of the vents was 42 degrees.
When I tried to figure out why it still held pressure before I put 36oz into the system kind of stumped me. I figured that since the truck was not driven for a year, the seals dried up since lube was not circulated through the system and caused slow leaks. If I get a 2-3 years on this current charge before a new recharge is needed would be good.
I, too, have thought that the system needed to be vacuumed before putting in refrigerant so that the correct amount is put in. However, the cost of having the system evacuated is expensive vs. topping off the system. I've charged 3 vehicles this way and have been successful each time by using accepted pressure ranges, with respect to ambient temperature. I have also found that all of my daily drivers that have the ACs used regularly have not needed recharges for years, while my cars that didn't see the road as often required refrigerant more often. I don't know if there is any truth to that, since there are tons of variables like connection and hose materials and system design. These are just observations I have made.
When I tried to figure out why it still held pressure before I put 36oz into the system kind of stumped me. I figured that since the truck was not driven for a year, the seals dried up since lube was not circulated through the system and caused slow leaks. If I get a 2-3 years on this current charge before a new recharge is needed would be good.
I, too, have thought that the system needed to be vacuumed before putting in refrigerant so that the correct amount is put in. However, the cost of having the system evacuated is expensive vs. topping off the system. I've charged 3 vehicles this way and have been successful each time by using accepted pressure ranges, with respect to ambient temperature. I have also found that all of my daily drivers that have the ACs used regularly have not needed recharges for years, while my cars that didn't see the road as often required refrigerant more often. I don't know if there is any truth to that, since there are tons of variables like connection and hose materials and system design. These are just observations I have made.
If the system still has pressure which is above the atmospheric pressure, there is no need to vacuum, as no outside air or moisture will make it inside the system. It is the fully empty systems that should be vacuumed to remove moisture and outside air.
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Originally Posted by Dave Sherman
Since there's a mechanical seal at the compressor shaft, it could still ooze tiny amounts of refrigerant over years. It's not like the compressor in your home A/C or refrigerator where all the moving parts are sealed inside the compressor housing. I had a leaky schrader on my last vehicle that would leak; if I unscrewed the dust cap on the low side fitting I could hear a brief hiss. That one did leak down to the point it stopped working completely, and when I discovered the leaky schrader I made sure to screw the cap on tightly after having it recharged. Seemed to fix it, but if I unscrewed the cap it still made a little "psst".
I do remember it being explained to me, that, as an AC system in a car is running, there has to be a tiny bit of leakage by design or it will not work properly. Further, that when the compressor is spinning, there is a tiny bit escaping past the shaft, this may or may not have been the tiny bit being referred to. I understand that it transfers heat out of the cabin and puts it in the engine bay behind the radiator, for a nice air to air transfer of heat helped by the fans that pull air. Where the vents that pull the air from the cabin are, I never did know, of course it different for every car I would think. But while true that if you have to add some or if it stops being cold this indicates a leak, the cars that need to be "topped off" every summer, that should not be.. The better question maybe would be, how long would that leak that is supposed to be there need in order to make the system not work? Or am I wrong here
Since there's a mechanical seal at the compressor shaft, it could still ooze tiny amounts of refrigerant over years. It's not like the compressor in your home A/C or refrigerator where all the moving parts are sealed inside the compressor housing. I had a leaky schrader on my last vehicle that would leak; if I unscrewed the dust cap on the low side fitting I could hear a brief hiss. That one did leak down to the point it stopped working completely, and when I discovered the leaky schrader I made sure to screw the cap on tightly after having it recharged. Seemed to fix it, but if I unscrewed the cap it still made a little "psst".
I do remember it being explained to me, that, as an AC system in a car is running, there has to be a tiny bit of leakage by design or it will not work properly. Further, that when the compressor is spinning, there is a tiny bit escaping past the shaft, this may or may not have been the tiny bit being referred to. I understand that it transfers heat out of the cabin and puts it in the engine bay behind the radiator, for a nice air to air transfer of heat helped by the fans that pull air. Where the vents that pull the air from the cabin are, I never did know, of course it different for every car I would think. But while true that if you have to add some or if it stops being cold this indicates a leak, the cars that need to be "topped off" every summer, that should not be.. The better question maybe would be, how long would that leak that is supposed to be there need in order to make the system not work? Or am I wrong here
Originally Posted by talest
Originally Posted by Dave Sherman
Since there's a mechanical seal at the compressor shaft, it could still ooze tiny amounts of refrigerant over years. It's not like the compressor in your home A/C or refrigerator where all the moving parts are sealed inside the compressor housing. I had a leaky schrader on my last vehicle that would leak; if I unscrewed the dust cap on the low side fitting I could hear a brief hiss. That one did leak down to the point it stopped working completely, and when I discovered the leaky schrader I made sure to screw the cap on tightly after having it recharged. Seemed to fix it, but if I unscrewed the cap it still made a little "psst".
I do remember it being explained to me, that, as an AC system in a car is running, there has to be a tiny bit of leakage by design or it will not work properly. Further, that when the compressor is spinning, there is a tiny bit escaping past the shaft, this may or may not have been the tiny bit being referred to. I understand that it transfers heat out of the cabin and puts it in the engine bay behind the radiator, for a nice air to air transfer of heat helped by the fans that pull air. Where the vents that pull the air from the cabin are, I never did know, of course it different for every car I would think. But while true that if you have to add some or if it stops being cold this indicates a leak, the cars that need to be "topped off" every summer, that should not be.. The better question maybe would be, how long would that leak that is supposed to be there need in order to make the system not work? Or am I wrong here
One of the cars I maintain is 13 years old and has never had any AC service. Just measured the discharge temp and it was 40F on a 90F day. A "tiny bit of leakage by design" you mention over 13 years in SoCal would be total loss. So much for that old wives tale.
Originally Posted by Dave Sherman
Since there's a mechanical seal at the compressor shaft, it could still ooze tiny amounts of refrigerant over years. It's not like the compressor in your home A/C or refrigerator where all the moving parts are sealed inside the compressor housing. I had a leaky schrader on my last vehicle that would leak; if I unscrewed the dust cap on the low side fitting I could hear a brief hiss. That one did leak down to the point it stopped working completely, and when I discovered the leaky schrader I made sure to screw the cap on tightly after having it recharged. Seemed to fix it, but if I unscrewed the cap it still made a little "psst".
I do remember it being explained to me, that, as an AC system in a car is running, there has to be a tiny bit of leakage by design or it will not work properly. Further, that when the compressor is spinning, there is a tiny bit escaping past the shaft, this may or may not have been the tiny bit being referred to. I understand that it transfers heat out of the cabin and puts it in the engine bay behind the radiator, for a nice air to air transfer of heat helped by the fans that pull air. Where the vents that pull the air from the cabin are, I never did know, of course it different for every car I would think. But while true that if you have to add some or if it stops being cold this indicates a leak, the cars that need to be "topped off" every summer, that should not be.. The better question maybe would be, how long would that leak that is supposed to be there need in order to make the system not work? Or am I wrong here
One of the cars I maintain is 13 years old and has never had any AC service. Just measured the discharge temp and it was 40F on a 90F day. A "tiny bit of leakage by design" you mention over 13 years in SoCal would be total loss. So much for that old wives tale.
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If it's a Ford Taurus with the swiveling hose joints, the answer is yes.
Quote
One of the cars I maintain is 13 years old and has never had any AC service. Just measured the discharge temp and it was 40F on a 90F day. A "tiny bit of leakage by design" you mention over 13 years in SoCal would be total loss. So much for that old wives tale.
ASE even refers to the fact that most all mobile air conditioning systems WILL leak a bit of r134a refrigerant over the life span of the unit. They've even scientifically observed
the typical loss at between .25 and .50 ounces per year in correctly functioning mobile AC systems.
Mobile AC certification training manual.
One of the cars I maintain is 13 years old and has never had any AC service. Just measured the discharge temp and it was 40F on a 90F day. A "tiny bit of leakage by design" you mention over 13 years in SoCal would be total loss. So much for that old wives tale.
ASE even refers to the fact that most all mobile air conditioning systems WILL leak a bit of r134a refrigerant over the life span of the unit. They've even scientifically observed
the typical loss at between .25 and .50 ounces per year in correctly functioning mobile AC systems.
Mobile AC certification training manual.
Originally Posted by AC1DD
Quote
One of the cars I maintain is 13 years old and has never had any AC service. Just measured the discharge temp and it was 40F on a 90F day. A "tiny bit of leakage by design" you mention over 13 years in SoCal would be total loss. So much for that old wives tale.
ASE even refers to the fact that most all mobile air conditioning systems WILL leak a bit of r134a refrigerant over the life span of the unit. They've even scientifically observed
the typical loss at between .25 and .50 ounces per year in correctly functioning mobile AC systems.
Mobile AC certification training manual.
But he stated it had to leak to work properly:
"I do remember it being explained to me, that, as an AC system in a car is running, there has to be a tiny bit of leakage by design or it will not work properly".
I should have quoted that also.
ASE says a lot of things to CYA.
That said, I agree that most leak a bit and work fine. Just disagree they have to leak to work.
Quote
One of the cars I maintain is 13 years old and has never had any AC service. Just measured the discharge temp and it was 40F on a 90F day. A "tiny bit of leakage by design" you mention over 13 years in SoCal would be total loss. So much for that old wives tale.
ASE even refers to the fact that most all mobile air conditioning systems WILL leak a bit of r134a refrigerant over the life span of the unit. They've even scientifically observed
the typical loss at between .25 and .50 ounces per year in correctly functioning mobile AC systems.
Mobile AC certification training manual.
But he stated it had to leak to work properly:
"I do remember it being explained to me, that, as an AC system in a car is running, there has to be a tiny bit of leakage by design or it will not work properly".
I should have quoted that also.
ASE says a lot of things to CYA.
That said, I agree that most leak a bit and work fine. Just disagree they have to leak to work.
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Originally Posted by mk378
Don't "top off", use a machine to pull it all out (and measure how much came out, to confirm the theory that some has leaked out over the years) then recharge with the specified amount by weight. This is the only way to be sure the charge is correct.
With gauges, verifying pressures, you can determine the proper charge and because you are not dealing with a "blended" refridgerant like in residential units, there is no reason to evacuate the whole system just to top off. If the system has gone empty, then you need to evac. the system prior to refilling.
Don't "top off", use a machine to pull it all out (and measure how much came out, to confirm the theory that some has leaked out over the years) then recharge with the specified amount by weight. This is the only way to be sure the charge is correct.
With gauges, verifying pressures, you can determine the proper charge and because you are not dealing with a "blended" refridgerant like in residential units, there is no reason to evacuate the whole system just to top off. If the system has gone empty, then you need to evac. the system prior to refilling.
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Originally Posted by demarpaint
Originally Posted by scurvy
Most vehicle AC systems leak a little, especially as they age. There is no perfect seal, especially in vibrating, heat cycling, cramped engine bay. Both our cars need a little top up once in a while. My Golf needs a minor top up every other year; the Mazda has needed a tiny bit once .
That's what my FIL told me years ago, he was an HVAC guy and did auto AC for many years. Some leak a little.
I work with industrial electricians, several of whom are licensed, unionized, industrial HVAC guys. Every single one of them has the kwik-kool-in-a-can with the cheesy gauge on top in their garage and that's all they've used on their cars or their family's cars. Not cooling as well but works ok otherwise? Give it a lil top-off. The entire-system-must-be-evacuated-and-refilled-by-weight-only chorus isn't wrong, it's just massive overkill in most cases. Safest, maybe. Most thorough, probably. Etc... - yes. But not necessary 95% of the time.
Even better, if you've got gauges on the low and high sides you can get a pretty darn good idea of the total system charge with a PT chart and how well the system works with a thermometer stuck in the vents...
Originally Posted by scurvy
Most vehicle AC systems leak a little, especially as they age. There is no perfect seal, especially in vibrating, heat cycling, cramped engine bay. Both our cars need a little top up once in a while. My Golf needs a minor top up every other year; the Mazda has needed a tiny bit once .
That's what my FIL told me years ago, he was an HVAC guy and did auto AC for many years. Some leak a little.
I work with industrial electricians, several of whom are licensed, unionized, industrial HVAC guys. Every single one of them has the kwik-kool-in-a-can with the cheesy gauge on top in their garage and that's all they've used on their cars or their family's cars. Not cooling as well but works ok otherwise? Give it a lil top-off. The entire-system-must-be-evacuated-and-refilled-by-weight-only chorus isn't wrong, it's just massive overkill in most cases. Safest, maybe. Most thorough, probably. Etc... - yes. But not necessary 95% of the time.
Even better, if you've got gauges on the low and high sides you can get a pretty darn good idea of the total system charge with a PT chart and how well the system works with a thermometer stuck in the vents...
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