AC leak issue

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Jul 14, 2019
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36
Location
Fairmont WV
I haven't had AC in my 95 since I bought it. The compressor had went out so the previous owner removed it and put the old compressor and lines in a box. I bought a new Denso compressor, new seal kit and belt. I put new seals in both ends of the lines, vacuumed it out, charged with argon and left it set for 30 min to test for leaks. I even sprayed soapy water around all the fittings to watch for bubbles and nothing. It didn't leak even a smidge on the gauge so filled it with 134a. The AC worked perfect that evening and my drive to and from work the next day. Last night i went to come home from work and its blowing hot. The compressor is on so there's enough freon to keep it working but not produce any cold air. I didn't replace the dryer or condenser but may have to go down that road. I'm just puzzled that the argon didn't leak at all unless its just a super slow leak. I need to put my gauges back on tonight and see how much freon leaked out but does anyone have any opinions on where else to check?
 

cvenom96

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Frederick, MD
Mine had several leaks at the condensor on the bottom. Couldn't see/hear it but after putting the UV dye in the system I was able to see it. The evaporator core under the dash had a small leak as did the o-rings. My experience after chasing leaks for a few months was pull all the connections apart, clean, and replace the o-rings. I replaced the evap. core, condensor, dryer, and compressor. That was years ago and it's been fine ever since.
 
Joined
Jul 14, 2019
Messages
36
Location
Fairmont WV
I need to find some dye and go that route i think but i hate the thought of pulling the evap core out. It only blew cold for that day and a half. After that its been warm since.
 

flintknapper

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Mine had several leaks at the condensor on the bottom. Couldn't see/hear it but after putting the UV dye in the system I was able to see it. The evaporator core under the dash had a small leak as did the o-rings. My experience after chasing leaks for a few months was pull all the connections apart, clean, and replace the o-rings. I replaced the evap. core, condensor, dryer, and compressor. That was years ago and it's been fine ever since.

^^^^^

Done correctly. 👍

Easier/best sometimes to just get it over with.
 

flintknapper

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I haven't had AC in my 95 since I bought it. The compressor had went out so the previous owner removed it and put the old compressor and lines in a box. I bought a new Denso compressor, new seal kit and belt. I put new seals in both ends of the lines, vacuumed it out, charged with argon and left it set for 30 min to test for leaks. I even sprayed soapy water around all the fittings to watch for bubbles and nothing. It didn't leak even a smidge on the gauge so filled it with 134a. The AC worked perfect that evening and my drive to and from work the next day. Last night i went to come home from work and its blowing hot. The compressor is on so there's enough freon to keep it working but not produce any cold air. I didn't replace the dryer or condenser but may have to go down that road. I'm just puzzled that the argon didn't leak at all unless its just a super slow leak. I need to put my gauges back on tonight and see how much freon leaked out but does anyone have any opinions on where else to check?

IF the compressor *in the box* failed and sent metal particles through the system....then I would have advised flushing the lines and replacing all other components. But we don't know that to be the case.

I would certainly start by putting your gauges on it and seeing what the pressures are. It's possible you simply have a leak and low refrigerant charge now. So do that first.

In the future any time the system has been open to atmosphere for a significant amount of time *hours or more*....replace it.

Did you pull a deep vacuum on the system prior to recharging with refrigerant? From reading your post it sounds like you pulled a vacuum, then introduced argon then went ahead and filled the system, which would be out of order....is why I ask.

Let us know what you find for pressures *and the ambient temp when you did it*.
 
Last edited:
Joined
Jul 14, 2019
Messages
36
Location
Fairmont WV
We actually did argon for 30 min, pulled vacuum for 25 min, then filled the system with 134a. My dad used to have his refrigeration certs so he still has all his gauges and tools that I borrowed. I agree with putting the gauges back on and see how much has leaked out. It was 90 out when we filled it so the charge said to go 45-55 on the low pressure side. We stopped at 50. I think I may just order a new condenser and dryer since ill have the connections apart anyways. My 80 has 308k miles on it so it wont hurt to replace both. I will keep you guys updated what I find this evening pressure wise though. Appreciate the help!
 

flintknapper

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We actually did argon for 30 min, pulled vacuum for 25 min, then filled the system with 134a. My dad used to have his refrigeration certs so he still has all his gauges and tools that I borrowed. I agree with putting the gauges back on and see how much has leaked out. It was 90 out when we filled it so the charge said to go 45-55 on the low pressure side. We stopped at 50. I think I may just order a new condenser and dryer since ill have the connections apart anyways. My 80 has 308k miles on it so it wont hurt to replace both. I will keep you guys updated what I find this evening pressure wise though. Appreciate the help!

Gotcha. Sounds good, take the readings and let us know. Then when/if you change the other components you can start anew with the evacuation, pump down and recharge. I can walk you through it if need be....or do a search here, we've gone over it many times with others. But happy to help if you need anything.

There are several knowledgeable folks here concerning A/C repairs and system recharging. All have been willing to help our members here in the past. So don't hesitate to ask if you need the help or just hit a stumbling block.

We simply don't know the level of experience of each person doing their own work....and with A/C work you don't want to be half way through the procedure and discover you've done something wrong. It can be an expensive and time consuming lesson.
 

cvenom96

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Frederick, MD
Your system sounds like mine. Like I mentioned, after a few tries of pulling a vacuum and it seeming to hold but leak once charged, I put the UV dye in and found all of the other leaks. That was when I took the nuclear option and just replaced it all. In a lot of cases on this truck, that's what I've found has been the most efficient way of dealing with maintenance/repairs. Otherwise I just keep chasing the next weakest link.....
 

flintknapper

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Deep East Texas
Your system sounds like mine. Like I mentioned, after a few tries of pulling a vacuum and it seeming to hold but leak once charged, I put the UV dye in and found all of the other leaks. That was when I took the nuclear option and just replaced it all. In a lot of cases on this truck, that's what I've found has been the most efficient way of dealing with maintenance/repairs. Otherwise I just keep chasing the next weakest link.....
^^^^ 👍
One of the pitfalls of A/C work is that sometimes the system will hold 'vacuum' but not pressure. This is especially true of compressor front seals and pin holes in rubber barrier hoses. Their natural position being under pressure, then when a vacuum is applied it tends to pull the 'leaky' part back inward and make a suitable seal. Only to fail again once pressure is exerted on it.

Just one of those 'quirks' that can be very frustrating.

Too....if you've found leaks at Orings/mating surfaces....chances are....all of them need to be checked. The Orings deteriorate over time or take a 'compression set'. That is why I recommend the use of Nylog when lubricating Orings and fitting mating surfaces *much to the distress of certain folks*. ;)

In situations such as yours....if finances and time will allow, you did the best thing.
 

cvenom96

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Yep @flintknapper that was exactly my assumption. The vacuum pulled them a certain way and/or allowed them to expand ever so slightly and seal enough to hold vacuum. Once pressure was applied, fail!
 
Joined
Jul 14, 2019
Messages
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Location
Fairmont WV
Ill keep you guys posted. I greatly appreciate all the help and I know components can be a tad worn out after 300k miles. Where's a good place to get the dye from?
 

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