Checking for A/C Leaks after installing A New Evap Core

[SStripes]

Hello,
I came across this forum when researching for reasons as to why my A/C stopped working. It didn't take long for me to come across the infamous TSB for the evap core as well as the $2500+ qutoes to fix the issue. So i decided to do it myself and im at the point were i have installed the new evap core and sealed up the climate control housing. This is the part were I'd like to ask for some help from those who have done this job before.

How do I go about leak testing the A/C system while my dash is off. I already have an A/C manifold Guage set and my battery is back in the car (still disconnected though). Im guess i have to add refrigerant but how do I even do that when i have no way of turning the A/C system on due to lack of buttons. Ive also heard that the clutch for the compressor can get stuck when low on refrigerant how do fix this.

Some help would be greatly appreciated

P.S: I have some other things I'd like to ask about regarding this job but this is the most important right now.

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[Brokestang]

By using a vacuum pump.

 

[mindo389]

You could pressurize the system with nitrogen (preferred, as its a dry, inert gas) or with refrigerant and use Dawn liquid dish soap mixed with some water and spray it on the joints. Look for bubbles...

 

[SStripes]

Thx for the responses, I just picked up an air vacuum pump from Harbor Freight. Its probably better to go this route since the lines have most likely built up some moisture.

 

[SStripes]

You could pressurize the system with nitrogen (preferred, as its a dry, inert gas) or with refrigerant and use Dawn liquid dish soap mixed with some water and spray it on the joints. Look for bubbles...

Hey Mindo, im really glad you saw this thread since it was yours and Rod Schneider posts that I have seen.

Do you happen to remember if you had to do anything to the compressor clutch for it to engage when charging your A/C? I've heard that they can get stuck when there's little to no pressure in the lines

 

[Whitedevil95]

When I did a killer chiller back on my 2003 Cobra I pulled vacuum on the system then sealed the manifold gauge set. Wrote down the numbers and then made sure they never changed overnight. This told me the system was sealed tight.

 

[SStripes]

When I did a killer chiller back on my 2003 Cobra I pulled vacuum on the system then sealed the manifold gauge set. Wrote down the numbers and then made sure they never changed overnight. This told me the system was sealed tight.

I was only gonna do it for a couple of minutes but I realistically don't have much time to do much else today. I'll look up how to use this vacuum pump and set it up, thx for the tip.

 

[jloshotz]

Pull a vac on the system, then feed a little refrigerant (or nitrogen if you’ll be just doing bubble search without a quality leak detector) through the high side, you’ll see the low side pressure rise as it feeds through the system. Feed until your low side gauge is showing a good amount of pressure (60~120ish should be plenty) then do your bubble search

 

[SStripes]

Pull a vac on the system, then feed a little refrigerant (or nitrogen if you’ll be just doing bubble search without a quality leak detector) through the high side, you’ll see the low side pressure rise as it feeds through the system. Feed until your low side gauge is showing a good amount of pressure (60~120ish should be plenty) then do your bubble search

Add refrigerant while the car is off? Should it hold pressure once it makes it to that 60-120ish

 

[jloshotz]

Absolutely and yes

 

[5doorsoffury]

usally when theres a suspected leak you would add some uv dye and take a look around with a uv lamp. if your fancy and have a kit they come with goggles to filter out other light.

 

[jloshotz]

To each his own with that dye. I’m a tech with 35 years dealing with HVAC/R, and never believed in it. Bottom line, the ONLY two things that belong in ANY A/C or refrigeration system are Refrigerant, and refrigerant oil. Period. Dyes and sealants are pure garbage. Sorry. Nothing like getting that yellow/green trash all over the place when you hit the access ports.

 

[SStripes]

To each his own with that dye. I’m a tech with 35 years dealing with HVAC/R, and never believed in it. Bottom line, the ONLY two things that belong in ANY A/C or refrigeration system are Refrigerant, and refrigerant oil. Period. Dyes and sealants are pure garbage. Sorry. Nothing like getting that yellow/green trash all over the place when you hit the access ports.

Out of curiosity, do you know how mouse fur would find its way into my Evaporator core Even though it's sealed off with from were the mouse entered the Climate control housing

 

[SStripes]

Out of curiosity, do you know how mouse fur would find its way into my Evaporator core Even though it's sealed off with from were the mouse entered the Climate control housing

Also, what would happen if you'd try to charge the system while said mouse fur was on the evaporator core? Would large mist of refrigerant come out from within the engine bay and car vents?

 

[mindo389]

Usually, I would leak test systems around 10-15 psig. This would help find large leaks, without blowing the soap off the joints or polluting the atmosphere with refrigerant blowing everywhere. Then I'd pressurize the system to around 50 psig, then look for small leaks. I had electronic leak detectors when I did service work, but soap does OK. Once you determine your lines aren't leaking, you should weigh your refrigerant in. There's scales cooks use that would work. I think around $15 I paid for mine that I bake with. But I used refrigerant scales I had when I was working. You shouldn't have to run your compressor to charge 1.5 lbs r-134a, if the bottle is warm enough. Jloshotz is correct about dyes...

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