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New A/C Leak

4K views 28 replies 7 participants last post by  Astro Pop 
#1 ·
My a/c compressor was replaced 4 years ago and the A/C was running fine with a need to recharge each spring. However, this year, I had bought an Manifold gauge kit and noticed that I had not freon in the system. I pulled a vacuum and let it sit for an hour. It went from 23 hg down to 15. So, is that too much? Can I use a can of freon with stop leak to fix?
 
#2 ·
Sorry to say but "running fine" and "a need to recharge each spring" are not synonymous. You obviously have a problem and need to fix it. Letting that refrigerant escape into the atmosphere is not eco-friendly.

The stop leak types will destroy your A/C system. Never use those. Use refrigerant with dye to find the leaks and then repair them.
 
#3 ·
I always disable the system so it cannot come on, fill system with nitrogen and check for leaks with soap. I use a micron gauge for my vac. a leak would show as an increase in the number e.g. 450 rising to 600 microns. I've used the freon with the stop leak with about 50% success. Hope this helps, Steve.
 
#6 ·
dnwong said:
Will this guy work instead of a dye and black light?

http://www.harborfreight.com/electronic ... 92514.html
Good question. It may as long as the leak is big enough. With the engine running I doubt you would get reliable readings and with it off maybe the system doesn't leak enough. It may be worth a try but definitely not for $69 on sale! Amazon has those for about $30.
 
#7 ·
Dye will let you pinpoint it better. Elec leak detectors will tell you "Somewhere around the rear of the compressor". Dye will tell you "The connection on the left side of the manifold".

Plus, once you buy the blacklight, you can re-visit all those old Jimi Hendrix posters plus hunt for scorpions.

Lump
 
#8 ·
Another way to leak check the system is to use a compressor. I just pump about 40 psi into the system and then shoot soapy water from a spray bottle, if it isn't loud enough to hear. Just don't go too high on the air pressure, you might blow something out on the low side of the system. This a cheaper and you don't end up buying tools you'll never use again. But I do have some Jimi Hendrix posters I'd sell you.
 
#9 ·
Astro Pop said:
Another way to leak check the system is to use a compressor. I just pump about 40 psi into the system and then shoot soapy water from a spray bottle, if it isn't loud enough to hear. Just don't go too high on the air pressure, you might blow something out on the low side of the system. This a cheaper and you don't end up buying tools you'll never use again. But I do have some Jimi Hendrix posters I'd sell you.
Yes, I think I will go the air compressor route. Sounds less evasive.
 
#11 ·
I vacuumed and filled with Freon/Oil. The compressor started cycling but it would just come on and go off. It won't stay on. Low side pressure 40-50 but high side pressure no more than 50. Does not feel like it is taking any more freon. Ideas?
 
#13 ·
Astro Pop said:
Another way to leak check the system is to use a compressor. I just pump about 40 psi into the system and then shoot soapy water from a spray bottle, if it isn't loud enough to hear. Just don't go too high on the air pressure, you might blow something out on the low side of the system. This a cheaper and you don't end up buying tools you'll never use again. But I do have some Jimi Hendrix posters I'd sell you.
Please don't use compressed air, it has too much moisture, the sworn enemy of any system that carries freon. Always use nitrogen, you can use freon to find a leak but bad for the environment. A good freon sniffer can bring you to the leak however the good ones are over $200. The dye works good too. I would recommend replacing the orifice and filter drier. The high side pressure is way off, are those pressures taken when compressor running? Did you add the EXACT amount of freon stated on the under hood label?
 
#16 ·
Astro Pop said:
You didn't say what you found in the leak area thus we don't know where you worked. That might lead to some answers. Also how much 134 did you get in? Do you have rear A/C? How long did the vacuum hold? Inquiring minds have to know.
Have not found the leak yet. Wanted to make sure all other components worked first and then I will try the dye method. I don't have a rear A/C. I will check today to see what is in the system and if I can add more freon to get keep the compressor from constantly cycling.
 
#17 ·
The system can also cycle if the high side is going too high... a condition caused by overheating and over pressure by not pulling enough air across condenser. My original electric fans were very inadequate at idle, and this condition happened to me. A properly shrouded powerful fan solved this particular issue.

I've never seen a definitive answer on what the gauges "should" read.. and of course it varies from different manufacturers. Typically, I find a good "ballpark" figure about 225-250 high and 25-30 low... but haven't found the "ideal" numbers yet. Certainly other things may cause variations too. The trouble with topping off a system with more freon and a 30lb tank, is that there is no way of knowing how much freon you already have in system.

If you have air in the system, you will also get false readings too. It is always recommended to vacuum the system first when filling an empty system.

Overcharging can be worse than undercharging too.

I find it typical to have to recharge my vehicles at least yearly. It seems once you tap the system... it always bleeds down with time. There is a certain amount of natural leakage due to molecular composition and older seals.

If you've got an actual leak then fix it... it won't fix itself! Good luck!
 
#21 ·
Do any of the cans of freon you're wasting have dye in them? At least some good will come of it if there is one can of dye. The odds are 99% the rest of the system is okay if all you've experienced so far is a small leak. The low pressure switch is designed to save the compressor and other components if the freon gets low.
First things first, find and fix the leak, otherwise you're wasting your time and $$$. Once the leak is found and fixed, pull a really good vacuum. 29 inches.
On an earlier posting you said you pulled a vacuum so I assume you have access to a good vacuum pump. I always pull a vacuum for a minimum of 2 hours before I'll even think of recharging. That time will boil off all moisture to ensure a good dry beginning. Also let it sit for 30 minutes without the pump running to check for any leaks. If it drops any more than a minuscule amount in that time go recheck for a leak.
I know using compressed air to locate a leak introduces moisture, but absent more sophisticated tools, it works great and pulling a long vacuum before recharging boils off the moisture especially on a good warm day.
Attached is a photo of the low pressure switch and connector (pic 1). It's on the back of the accumulator (big silver can thingie in the right front of the engine compartment). When you go to recharge the system pull the connector plug and put a small wire across the two holes in the connector (pic 2) to bypass the low pressure switch and force the compressor to run continually. And as suggested turn the cans upside down to draw fluid into the feeder hose. Keep the wire in until the pressures come up to normal and the system stabilizes. At this point you should be running back and forth to the cab to constantly check the temp coming out the vents. If it gets good and cold and you add more freon and the temp goes up, you've just added too much. Bleed it off a little and be happy with the temp you have. One more thing not mentioned very often but important is to seal the van up. All windows closed, doors closed and A/C setting to Max. The A/C system recycles the inside air to get the lowest possible temp.
If during this process the hi side starts climbing too hi stop the engine and pull the wire, you have a problem. If it all acts normal after about 4 cans then turn the van off pull the wire out, plug it back in to the switch, restart the van and turn on the A/C to recheck the pressures and temp.
Following these procedures will give you a system that will last several years without needing to touch it.
Pardon my carrying on about this but I made my living doing auto repairs and get a little wound up at times, so I clarify things a little too enthusiastically.
 

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#22 ·
I added more freon and the clutch stayed on much longer. 5 -10 mins later, I heard metal scraping and it appears that compressor is starting to seized up. I turned to car off immediately and let it sit for a moment. When I restarted the engine with the a/c off, the clutch was spinning freely. However, once I turned the a/c on, the metal squealing started again. Looks like the compressor is shot (probably the source of the leak too... lol). Anyways its was a Advance Auto compressor replaced 3-4 years ago. So, probably out of warranty. Where is the best place to get a affordable replacement?
 
#23 ·
Advanced is where mine is from. They got a year warentee if you jump through the hoops. Buy the lines and filter. Have it installed by a shop. Or the warentee is no good.
What happened to the original? If it did a similar thing it has shaving in it probably causing the quicker demise of the pump. They got kits to flush things. It needs vacuumed because when they do this it creates acids.
So at the very least look for shavings in the line when it is apart.
 
#26 ·
Astro Pop said:
Do any of the cans of freon you're wasting have dye in them? At least some good will come of it if there is one can of dye. The odds are 99% the rest of the system is okay if all you've experienced so far is a small leak. The low pressure switch is designed to save the compressor and other components if the freon gets low.
First things first, find and fix the leak, otherwise you're wasting your time and $$$. Once the leak is found and fixed, pull a really good vacuum. 29 inches.
On an earlier posting you said you pulled a vacuum so I assume you have access to a good vacuum pump. I always pull a vacuum for a minimum of 2 hours before I'll even think of recharging. That time will boil off all moisture to ensure a good dry beginning. Also let it sit for 30 minutes without the pump running to check for any leaks. If it drops any more than a minuscule amount in that time go recheck for a leak.
I know using compressed air to locate a leak introduces moisture, but absent more sophisticated tools, it works great and pulling a long vacuum before recharging boils off the moisture especially on a good warm day.
Attached is a photo of the low pressure switch and connector (pic 1). It's on the back of the accumulator (big silver can thingie in the right front of the engine compartment). When you go to recharge the system pull the connector plug and put a small wire across the two holes in the connector (pic 2) to bypass the low pressure switch and force the compressor to run continually. And as suggested turn the cans upside down to draw fluid into the feeder hose. Keep the wire in until the pressures come up to normal and the system stabilizes. At this point you should be running back and forth to the cab to constantly check the temp coming out the vents. If it gets good and cold and you add more freon and the temp goes up, you've just added too much. Bleed it off a little and be happy with the temp you have. One more thing not mentioned very often but important is to seal the van up. All windows closed, doors closed and A/C setting to Max. The A/C system recycles the inside air to get the lowest possible temp.
If during this process the hi side starts climbing too hi stop the engine and pull the wire, you have a problem. If it all acts normal after about 4 cans then turn the van off pull the wire out, plug it back in to the switch, restart the van and turn on the A/C to recheck the pressures and temp.
Following these procedures will give you a system that will last several years without needing to touch it.
Pardon my carrying on about this but I made my living doing auto repairs and get a little wound up at times, so I clarify things a little too enthusiastically.
Thanks for the write-up. Looks like I will need to replace the compressor first before coming back to this...
 
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