AC Question
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Team Owner
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From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
AC Question
OK, everything is together and seems to be running great. I pulled some plugs today and they look fine. Still new, they need more miles on the to turn brown I guess.
Anyway, this has been going on for some time, even before the mods.
With the AC on the compressor will run for about 3 seconds, then shut off for about 4 seconds, then run for three seconds, then shut off for about 4 seconds.
The idle goes up and down, as it should, when the compressor cycles.
Now, the AC lines get ice cold as they should and the system blows very cold.
So the AC is doing the job it was designed to do, however, is the compressor supposed to cycle like that?
Other than the idle going up and down, there's no problem. It's just a little annoying.
Thanks
Anyway, this has been going on for some time, even before the mods.
With the AC on the compressor will run for about 3 seconds, then shut off for about 4 seconds, then run for three seconds, then shut off for about 4 seconds.
The idle goes up and down, as it should, when the compressor cycles.
Now, the AC lines get ice cold as they should and the system blows very cold.
So the AC is doing the job it was designed to do, however, is the compressor supposed to cycle like that?
Other than the idle going up and down, there's no problem. It's just a little annoying.
Thanks
Melting Slicks
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
on/off cycling of the compressor is normal to keep the evaporator from freezing up, however, 3-4 second intervals of cycling is to frequent. This will lead to early clutch failure. My guess is that your oriface tube may be clogged.
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Team Owner
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From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
The car has 33K miles and is in mint shape. It has always been garaged. Does that mean anything to you in terms of the tube clogging?
The system is R12 and if I have to evacuate it I just may wait for the clutch to go.
Melting Slicks
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
Let me just throw out a quote here:
Metering devices are used to regulate the flow of liquid refrigerant into the evaporator. They also serve as one of the two junctions between the high and low sides of the system. There are two basic types of metering devices used in A/C systems: fixed and variable.
Oriface Tube:
This is a fixed metering device(which is what our vettes have) located inside the liquid line between the condenser and evaporator. The orifice tube is enclosed within a plastic housing and protected by a fine mesh filter. The filter prevents debris from clogging the tube.
Yes, that is low miles, but do you know if the AC system has previously been serviced ?
Metering devices are used to regulate the flow of liquid refrigerant into the evaporator. They also serve as one of the two junctions between the high and low sides of the system. There are two basic types of metering devices used in A/C systems: fixed and variable.
Oriface Tube:
This is a fixed metering device(which is what our vettes have) located inside the liquid line between the condenser and evaporator. The orifice tube is enclosed within a plastic housing and protected by a fine mesh filter. The filter prevents debris from clogging the tube.
Yes, that is low miles, but do you know if the AC system has previously been serviced ?
Thread Starter
Team Owner
Joined: Oct 2004
Posts: 35,065
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From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
Let me just throw out a quote here:
Metering devices are used to regulate the flow of liquid refrigerant into the evaporator. They also serve as one of the two junctions between the high and low sides of the system. There are two basic types of metering devices used in A/C systems: fixed and variable.
Oriface Tube:
This is a fixed metering device(which is what our vettes have) located inside the liquid line between the condenser and evaporator. The orifice tube is enclosed within a plastic housing and protected by a fine mesh filter. The filter prevents debris from clogging the tube.
Yes, that is low miles, but do you know if the AC system has previously been serviced ?
Metering devices are used to regulate the flow of liquid refrigerant into the evaporator. They also serve as one of the two junctions between the high and low sides of the system. There are two basic types of metering devices used in A/C systems: fixed and variable.
Oriface Tube:
This is a fixed metering device(which is what our vettes have) located inside the liquid line between the condenser and evaporator. The orifice tube is enclosed within a plastic housing and protected by a fine mesh filter. The filter prevents debris from clogging the tube.
Yes, that is low miles, but do you know if the AC system has previously been serviced ?
I guess if my question is will a service solve/identify the problem (if it turns out to be that) or does the system need to be evacuated, taken apart, fixed, and reassembled and recharged?
Keep in mind, it's still R12. Is this going to be a problem?
Last edited by jsup; May 4, 2008 at 08:31 PM.
Pro
Joined: Sep 2006
Posts: 702
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From: Conyers Ga
It sounds like the compressor is short cycling. One of the most common causes is low freeon charge. The suction line is getting cold from the rapid rate of the cycling. I'd check your charge before ripping into the system to replace the orifice. If you have to replace it, take the old one to a pep boys and they can sell you a replacement based on the number stamped on it.
Of course if you don't have the license to buy the freeon, you're better off having it done by someone who does.
Of course if you don't have the license to buy the freeon, you're better off having it done by someone who does.
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Team Owner
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From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
It sounds like the compressor is short cycling. One of the most common causes is low freeon charge. The suction line is getting cold from the rapid rate of the cycling. I'd check your charge before ripping into the system to replace the orifice. If you have to replace it, take the old one to a pep boys and they can sell you a replacement based on the number stamped on it.
Of course if you don't have the license to buy the freeon, you're better off having it done by someone who does.
Of course if you don't have the license to buy the freeon, you're better off having it done by someone who does.
My concern is the R-12..I know someone in the AC business, hopefully they can help. I have two 1lb cans of R12 on my garage shelf, and a charge kit, hope we can use those.
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It sounds like the compressor is short cycling. One of the most common causes is low freeon charge. The suction line is getting cold from the rapid rate of the cycling. I'd check your charge before ripping into the system to replace the orifice. If you have to replace it, take the old one to a pep boys and they can sell you a replacement based on the number stamped on it.
Of course if you don't have the license to buy the freeon, you're better off having it done by someone who does.
Of course if you don't have the license to buy the freeon, you're better off having it done by someone who does.
....it really sounds like you have a low charge....some shops will throw on a set of refrigeration gauges for little of no cost and that should tell the tale....a clogged orifice tube will also show up as high pressure on the gauges......
Melting Slicks
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
Fick and GA are right on the money and I apologize for missing this. What you need to do is visually look at all your AC connection points for residue from a leak. Check the rubber hoses as well, as they can also develop pin hole leaks over time. I too have an R12 system in my '93, and this stuff costs more per ounce than gold !! (not really, but it will cost alot, assuming you can find a shop that still deals with R12).
Advanced
Joined: Sep 2007
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From: lexington nc
Easiest way to see if its low charge, turn a/c on full cold with max fan speed, the compressor should stay running or only cycle every few minutes, if compressor is still cycling fast, feel both lines coming through the firewall, if one is alot warmer than the other it very likely low on charge, someone with an old set of guages should be able to use the cans you have.
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From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
Cool, I'm going to have it measured.
I have 2 cans of R12 in the garage, what does it take to fill the system?
The cans are 12oz I believe.
Pro
Joined: Sep 2006
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From: Conyers Ga
I don't know the exact charge but 2 12 oz cans (1lb 8 oz) should be enough. Check the data plate in the engine compartment. If it IS low, and since you only have 2 cans of R-12, make sure they leak check the system before charging it.
Melting Slicks
Joined: Oct 2004
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From: Austin Texas
Thread Starter
Team Owner
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From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
That should be enough, no?
I also have the hose adapter for the can.
Problem. It's FORD MOTOCRAFT R12. Kinda like Jerry Sienfeld getting a blood transfusion from Newman, eh?
Melting Slicks
Joined: Oct 2004
Posts: 2,510
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From: Austin Texas
Just checked. I have FOUR 14oz cans. However, one is empty, guess over time it leaked out. So I have three cans, 14oz each.
That should be enough, no?
I also have the hose adapter for the can.
Problem. It's FORD MOTOCRAFT R12. Kinda like Jerry Sienfeld getting a blood transfusion from Newman, eh?
That should be enough, no?
I also have the hose adapter for the can.
Problem. It's FORD MOTOCRAFT R12. Kinda like Jerry Sienfeld getting a blood transfusion from Newman, eh?
Here ya' go:
Thread Starter
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From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
COOL!! So the entire system holds 36 ounces, I have enough and then some......excellent.
As for the 8oz of oil, is that in the freon, or do I have to get it separately? Is it as expensive as the gas?
As for the 8oz of oil, is that in the freon, or do I have to get it separately? Is it as expensive as the gas?
Melting Slicks
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
No, there is no oil in the R12 cans you have, unless it explicitly says so on the can.....It will probably be difficult to find R12 oil charge nowadays. Chances are, since your AC system is still cycling , you still have plenty of oil in the system....
Remember....make sure you first try to locate the leak. If you find that you have a bad hose, BLAM, it will have to be replaced, system will have to be evacuated, and re-charged. If this is the case, good to replace the oriface tube(chap) and the reciever dryer....
On the other hand, if you can't find a major source of leak, I would just give a quick "torque" to all the connections, hook up the gauges and charge to specified High/Low pressure....(I don't know these numbers off hand....)
A good rule of thumb is ~30psi on the Low side and ~200psi on the High.......
Remember....make sure you first try to locate the leak. If you find that you have a bad hose, BLAM, it will have to be replaced, system will have to be evacuated, and re-charged. If this is the case, good to replace the oriface tube(chap) and the reciever dryer....
On the other hand, if you can't find a major source of leak, I would just give a quick "torque" to all the connections, hook up the gauges and charge to specified High/Low pressure....(I don't know these numbers off hand....)
A good rule of thumb is ~30psi on the Low side and ~200psi on the High.......
Last edited by MikeC4; May 4, 2008 at 10:10 PM.
Thread Starter
Team Owner
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From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
No, there is no oil in the R12 cans you have, unless it explicitly says so on the can.....It will probably be difficult to find R12 oil charge nowadays. Chances are, since your AC system is still cycling , you still have plenty of oil in the system....
Remember....make sure you first try to locate the leak. If you find that you have a bad hose, BLAM, it will have to be replaced, system will have to be evacuated, and re-charged. If this is the case, good to replace the oriface tube(chap) and the reciever dryer....
On the other hand, if you can't find a major source of leak, I would just give a quick "torque" to all the connections, hook up the gauges and charge to specified High/Low pressure....(I don't know these numbers off hand....)
Remember....make sure you first try to locate the leak. If you find that you have a bad hose, BLAM, it will have to be replaced, system will have to be evacuated, and re-charged. If this is the case, good to replace the oriface tube(chap) and the reciever dryer....
On the other hand, if you can't find a major source of leak, I would just give a quick "torque" to all the connections, hook up the gauges and charge to specified High/Low pressure....(I don't know these numbers off hand....)
I'll copy that page and bring it with me.
Even if the entire system needs to be evacuated I have enough Freon.
I am going to do the following:
1. Perform a leak test
2. If leaks, fix them and fill it
3. If no leaks, top it off and keep the R12
If I have to refill it I have to find R12 oil. I did a quick Google and it seems to be available.
Make sense?
Melting Slicks
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
Yes, sounds good....but if you have to:
2. If leaks, fix them and fill it
You will need to draw down the system(ie vacuum down) to remove moisture from the system before you "fill it". Once you open your system to the atmoshere, air and mositure immediatley enter.....When I do R134 work, I duct tape an AC hose to my shop vac and hook it up to the Low side and let it suck for 30 minutes, then do the same on the High side....I have never had any problems with this method... I just refuse to pay these rediculous prices to "AC specialists" for work....It 'aint rocket science as they would have you believe....It's simple closed system refridgeration that has been around for decades!!!
2. If leaks, fix them and fill it
You will need to draw down the system(ie vacuum down) to remove moisture from the system before you "fill it". Once you open your system to the atmoshere, air and mositure immediatley enter.....When I do R134 work, I duct tape an AC hose to my shop vac and hook it up to the Low side and let it suck for 30 minutes, then do the same on the High side....I have never had any problems with this method... I just refuse to pay these rediculous prices to "AC specialists" for work....It 'aint rocket science as they would have you believe....It's simple closed system refridgeration that has been around for decades!!!
Last edited by MikeC4; May 4, 2008 at 10:22 PM.