AC Stop Leak?
- Thread starter Bozz10mm
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Since I do currently fix cars as a certified master tech I thought I should chime in...so although r 134a is not Ozone depleting it does contribute to the green house effect big time. Please don't just keep pumping freon into it, even with leak stop.
Like some others have stated, leak stop ime has never actually stopped any leak I have seen on an automotive system. Although it's well known for damaging recovery machines at shops. Anyhow, add some dye at next charge and use a UV light and halogen leak detector to isolate it. If it's not obvious and external it very well could be your evaporator core which is the in dash component.
During a professional diagnostic process you should certainly also observe gauge pressures as a compressor will also short cycle from high pressure not just low. On a typical Texas summer day you can expect the low side to run 32-44 psi and 220-260 psi on the high side on a properly charged system. Maybe a little higher on a dual unit or mechanical fan system but not much.
Like some others have stated, leak stop ime has never actually stopped any leak I have seen on an automotive system. Although it's well known for damaging recovery machines at shops. Anyhow, add some dye at next charge and use a UV light and halogen leak detector to isolate it. If it's not obvious and external it very well could be your evaporator core which is the in dash component.
During a professional diagnostic process you should certainly also observe gauge pressures as a compressor will also short cycle from high pressure not just low. On a typical Texas summer day you can expect the low side to run 32-44 psi and 220-260 psi on the high side on a properly charged system. Maybe a little higher on a dual unit or mechanical fan system but not much.
This is good info. I do have one of those cheapy gauges attached to a filler hose. I won't keep pumping R134 into the system, but now I am thinking about giving it one more shot with some A/C pro super sealer. The more modern leak sealers are oil based and shouldn't clog up the system or mess up the mechanics equipment. At least that's what I've been reading.
I'm heading to Advance Auto this morning to pick up a new battery for the Sonoma to replace the 7 year old one in it now. Preparing myself for sticker shock. I think I paid $125 7 years ago. I'll pick up some leak sealer and a can of R134a while I'm there.
I don't know why I keep the dang thing anyway. Sentimental reasons I guess. And it keeps me busy. Bought it new 26 years ago this month. Everything on it has been replaced at one time or another. 3 alternators, 2 water pumps, 2 radiators, ABS modulator, AC compressor, head gasket, starter, motor mounts, transmission, throttle position sensor, a leaky fuel injector, and probably stuff I can't think of off the top of my head. And it only has about 175k miles on it.
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seeker_two
My posts don't count....
Advanced Auto and other places should have proper gauges you can borrow to check your system. Some will even check it for you. Ask when you get there.
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Good idea. But then I'd have to charge the system in their parking lot, right? Don't think I want to do that. I'm just hoping they will install the battery for me so I don't have to make another trip to return the core.
If you have to take the battery home, be sure to check posts on the battery they give you.
I've had them give me a battery with post sides switched, and also smaller posts.
They replaced the battery for me. Saves me a trip back. I swear tho, I could have done it quicker, heh. Gold series battery was $160. So that's done. I went ahead and bought and installed the AC stop leak and some R134a. Must not have been as low as the first time because it only took about 5 seconds for the compressor to kick in and stay on. The stop leak has a red dye in it. I saw some red dye and tiny bubble at the low pressure schrader valve after I installed the R134. Ran it a few minutes and checked again, no dye, no bubbles. We'll see how long it lasts. It was putting out some pretty cold air.
Axxe55
Retiretgtshit stirrer
Cliff did mention the service ports leaking. Those caps are suppose to have sealing rubbers inside them. If the caps are missing, or the sealing rubbers are gone, buy some new caps at the auto parts store. The all will leak just a tiny bit if the caps are missing.
The cap does have a crack in it on the side. I'll replace it.
Yeah it does need to be replaced. But then I would have to take it to a shop and have it professionally evacuated and recharged. Probably several hundered dollars. I'm just being a cheapskate. Had the entire system replaced 7 years ago and that was around $1500. I don't want to put any more money into this old truck than I have to.
I'm thinking about buying a cheap vacuum pump and a set of gauges and doing it myself. I can always use it on my other vehicles.
Could just be loose. If you have a valve insert/remove tool might wanna give it a twist. If you don’t have one you can pick up an extremely cheap one at any auto parts store. Probably isn’t loose but, for the cost, eliminating that as a possibility isn’t a bad idea.
There you have it,
Pump, $60 on Amazon.
https://www.amazon.com/gp/product/B01N6IOBWF/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
Gauges probably about the same.
Then you are good to go and have the equipment in case you need it again.
Reality is... pulling a vacuum on the a/c has one purpose: extract moisture from the system. It accomplishes that by causing the water/moisture to boil allowing it to be vented to the atmosphere via the vacuum pump. It can also be used to determine if a system is leaking but that’s not the primary purpose.
Reality is... if you are going to simply replace a schrader valve the chances of introducing a significant amount of moisture into the system are pretty minimal. Consequently no “real” need to pull a vacuum on the system. Is it the best way? Nope. But your risk factor is actually quite small if you dont do it.
If you don’t know squat about low side/high side pressure ratios a set of gauges, no matter the cost, is a waste of money. You can get freon with a pressure gauge on it - they are available. Get on line and find out what range your high side pressure should be. The using the gauge on the refill can of freon... bring it to that pressure. That “should” get your system cooling again without introducing additional problems.
while on line find out how much freon your system requires, ~3#s iirc... from 30 or so years ago. Then put that much in. You’ll be starting from empty.
EDIT: I referenced high side pressure but I’m pretty sure it’s low side pressure for the freon can gauge. In any event... it comes with instructions.
Reality is... if you are going to simply replace a schrader valve the chances of introducing a significant amount of moisture into the system are pretty minimal. Consequently no “real” need to pull a vacuum on the system. Is it the best way? Nope. But your risk factor is actually quite small if you dont do it.
If you don’t know squat about low side/high side pressure ratios a set of gauges, no matter the cost, is a waste of money. You can get freon with a pressure gauge on it - they are available. Get on line and find out what range your high side pressure should be. The using the gauge on the refill can of freon... bring it to that pressure. That “should” get your system cooling again without introducing additional problems.
while on line find out how much freon your system requires, ~3#s iirc... from 30 or so years ago. Then put that much in. You’ll be starting from empty.
EDIT: I referenced high side pressure but I’m pretty sure it’s low side pressure for the freon can gauge. In any event... it comes with instructions.
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I have a valve core tool. Checked the schrader valve yesterday, but it was tight.
No disagreement here but I believe I recall the op indicating that wasn’t going to happen. Just presenting options short of taking it to a certified repair facility - which would be the “right” way for the op to solve this problem.
I've done some research over the past few days. I know what the high and low pressures are suppose to be. I also have a filler hose with a pressure gauge on it, but it only reads the low side pressure.
According to the owner's manual, the AC system requires 30 .oz of refrigerant. I only added about 12 oz to get the pressure up to about 40 lbs on the low side. It's putting out fairly cold air now. I just hope it holds.
I didn't realize I could bleed the system empty without introducing a lot of moisture into it. What about oil? Does that stay in the system, or do I need to add it back in?
