What a great no-nonsense video! No loud music, right to the point! Thank you!

I just use a rubber-tipped air nozzle directly on the manifold feed (yellow hose) inlet to put about 70 PSI in the system, close the manifold valves, then spray the hoses and connections with soapy water. Where you see bubbles is where you got troubles.

i see u are getting better after your stroke. im in the same boat. progress is slow but progress is seen. never give up never surrender

I really appreciated the amount of words you used. You didn't talk excessively but you definitely included enough detail to understand completely what you're saying. You also didn't have a long involved introduction and started the substantial parts of your video quickly. This is a skill that KZfaqrs with a million subscribers do not have. I will definitely watch more of your videos, as needed.

I stuck a schrader valve (from a bicycle tube) in a hose that I cut off of a can of AC Pro®. Then I held it together with a hose clamp. Putting air into the system was as easy as filling your tires.

I want to thank you for such a helpful video. I installed a new evaporator core in my 2005 Avalon last week. When I vacuumed the system it would not hold pressure. Using your method I found that the leak was coming from the new evaporator core! I returned it and when I installed another new one it’s sealed up perfectly. I never would’ve guessed the brand new part had a manufacturing defect but obviously it did. Thank you so much.

If like me you are a welder and have a CO2 bottle and regulator, you can tap off the regulator into the 1/4" threaded female port with a 1/4 MPT X refrigeration flare fitting, then you hook the gauge hoses directly to it use the regulator to control the flow and pressure. Never never use oxygen to pressurize anything that has oil in it, it can cause a serious explosion, that is why on oxygen gauges it says Use no oil. Using compressed air is not a great idea because compressed air contains moisture, moisture is not good in refrigeration or AC systems. I am also a Refrigeration tech I would use CO2 and soapy water to check for larger leaks, we flow it through the system when brazing connections it prevents soot from forming in the lines and also does not contain moisture like compressed air so it does not contaminate your oil with moisture and is easier to evacuate with a vacuum pump. Most people do not know this, but when you pull a vacuum on a system, it lowers the boiling point of moisture or water and the water will actually boil at room temperature , not only will it boil, but if you could touch it while it was boiling, it would be boiling at 32 degrees Fahrenheit. When I went to HVAC/ Refrigeration school our teacher had a jar with a HVAC gauge port brazed to the lid, inside was a Nyquil plastic does measuring cup with water in it. He asked any of us if we wanted to bet he could not make water boil at room temp, he then hooked up the vacuum pump to the jar, after about 20 minutes the water started bubbling to a boil, He asked someone to come up and put their finger in the water right after opening the jar, I remember the guy was shocked because the water was freezing cold. It was boiling with the heat from the room around 72 degrees Fahrenheit and the boiling temp of the water was 32 degrees. Crazy huh. That is physics, lower the pressure on a liquid and it lowers the boiling point. That is why they pull a vacuum on any AC system if it has lost it's Freon, otherwise moisture will mix with the refrigerant and the oil in the system which creates an acid that eats the windings and all the moving parts in the system and if moisture is inside a refrigerator or freezer sealed system, when the moisture hits the metering device, it can freeze and cause a restriction. Pulling a vacuum sucks out air moisture and all non condensables.

Dear Mr. Duane, alternatively, technicians in the middle east use a small bucket with soap water and sponge where they use the sponge to spread condensed soap over all potential AC leaking places while the system is under about 150 PSI air pressure. Thank you for such a wonderful videos. Take Care and Enjoy Your Heaven. John Jack Kaplanian.

Duane you’re a real hero. The fitting to use into your charging hose is 1/4” flare by 1/4” npt. This channel saved me a few times thanks for everything you do.

Great video Duane 👍. Here is another tip you could use a long hose to hear 👂 to pinpoint where the air leak is coming from. 🙏👋

I've been watching you for many years, Ive always appreciated your skill. Keep them coming

Thanks for this. I went so far as to machine my air fitting with 7/16 20 threads for a leak free connection. It took no time to find my Suburban rear a/c line was leaking back at a mounting bracket at the rear wheel. I'm in the rust belt so it was of little surprise. It took minutes to find the leak. I repaired the line, vacuumed it down, and refilled. Fixed the a/c in a few hours. Thanks!!!!

Yes, I've had a system hold perfect vacuum but fail the pressure test. The system runs with pressure, test it that way! Great video!

GREAT VIDEO, Duane ! I had replaced my compressor, but couldn't get the system into a vacuum. Using this technique I QUICKLY found a loose fitting on my gauge set ! BLOWING COLD NOW ! THANK YOU !!

Really like your very straightforward, simple approach. No fancy dancy stuff. Just practical stuff that works. And you explain it in terms I can understand. Thank you

Thank you for saving me $35 for dye, the air was free and it worked. I used a few of your videos for other repairs , as always they are easy to understand

Absolutely awesome. Love the old school way of doing repairs. I would listen to you any day!

Every time I watch, I learn something new. Can't express my appreciation for the content.

There are good mechanics & then there are "great" ones. You are one of them mister!!👍

Mr Duane, you are AWESOME always enjoyable learning from u thank you and appreciate the time it took to do this. cheeeeers

Good tip I always wondered if I could do this safely. By the way...those birds wanted to be famous on KZfaq

Always love your videos Duane. Your experience is unmatched! Thank you for sharing.

As a tech in this beautiful yet challenging field I can say we never stop learning and you sir have shown this old dog s few new tricks, thank you for that and Keep the videos coming.

Thank You Sir ! I been doing A/C systems for years. now thanks to your video I'll be saving time and money. i will discontinue the use of nitrogen to find a/c system leaks.

Thank you Duane. Glad to see your doing ok. Richard's Mobile Auto and Air. Thumbs up. Great Video

I just finished the job on my 2008 Honda Fit! I did exactly what you said and aired up the system into the green zone on my A/C gauge and when it was getting close to the red zone I unhooked it and carryed my air compressor to the back side of my house, so I wouldn't hear the air hissing. I crawled around the engine compartment with a bottle of windex. I could hear a slow his and sprayed windex on it and it turned out that my condenser had a leak right in the middle of it. My system only held pressure for 5 minutes. I then filled the system back up with air until it was in the green and started my car and turned on the A/C. The A/C clutch engaged then and then I knew my low pressure switch was working. After the system lost pressure the low pressure switch disengaged the A/C clutch. Thank you so much!

Nice to know you can use compressor air instead of nitrogen great 👍 thanks for sharing

Thank you for all your hard work and sharing your wealth of knowledge: You make learning interesting and fun , Thank You

Great video, and a good straight forward way to find a leak! I like to light a cigar or cigarette, though I rarely smoke, they are in my toolbox. Take and blow smoke into the charge port, then simply look for where it comes out. It works well for vaccum leaks as well.

Thank you for the information but the way glad to see you recovered very well.john

I discovered my truck AC had a pretty major leak when one day it worked and the next had nothing It was a pretty bad leak as vacuum applied was lost in a few minutes of leakdown time. Thought of how could I pressurize the system w/o wasting refrigerant. Thought of using my air compressor, searched internet, found your video and your video did the rest. One suggestion, somewhere along the line I got a cheapo plastic ac can valve/adapter and used that to connect to the air compressor and since it was plastic I used a bit of thread tape and screwed the air compressor adapter in hard cuz did not care about ruining the threads since I have 2 other can valve/adapters that are both brass. Used long fuel funnel as my hearing aid, found the leak fast, lol. Thank you again for good ideas. Wish I could post a pic of the refrigerant can valve I screwed the compressor fitting into, it worked a treat, including having the ability to turn the air on or off.

Thanks Duane. I always enjoy your videos and learn something.

thank you for your great wisdom and common sense approach to this problem !!! greatly appreciated !!!!!!

Thanks for your help and videos good luck on your recovery 👍

Once again thank you very much for All The tips you given ...bless you.

Mr fix it ....u probably know this but u can get a 1/4 npt male thread to male schrader fitting ....works great for what your doing.... Got two family (extended) members .....dad n daughter had a stroke at the same time....tough to watch....comeback is not easy...your a great teacher...

I bought a yellow hose that had the correct fitting on it to take a QR connector. Seemed worthwhile to allow cheap and environmentally friendly testing. Other than that minor difference, this is a great technique for leak diagnosis. The system will be full of moisture if it has a cracked pipe so I don’t see the issue with using shop air.

cool little black tape and I’m in the money ! $475 + tape ! I meant parts ! I’m kidding your born to teach - keep it coming.

Worked for me found a leak in the condensor, i knew the threads would be wrong but didn't think about just trying anyway, really only needed to get air into the system, then i disconnected and listened. prefect.

Great! Glad to see you making a new video. Keep them coming Duane...

Thanks a lot for this film. I also need to check most likely empty AC system. I even thought it is not possible. What a brilliant idea. I have one car in which AC stopped blowing cold air. It is our back up car, and since the attempts to repair it at dealer failed, we let it go like that without AC. It was 10 years ago, so most likely the AC system is empty, if it was a leak there. Dealer was complaining w/leak on the compressor seal they installed. They replaced the compressor like 2-3 times, but again it failed. Last time they wrote that the compressor is leaking at the central seam. Probably they had defective compressors or smth. I plan to attempt to repair that AC, since learned a bit about cars.

Great tip, thanks for sharing with us! Look forward to putting it to use!

Great video Duane, thank you! I bought the tool too.

Great video. I learned several good concepts! Thanks for your insights!!

Common sense approach, thank you Sir for sharing.

Ray Charles could’ve seen that leak point! But very good technique. Love your videos they’re very informative thanks!

Duane, you are the ultimate teacher 🧑‍🏫 your videos are always a learning experience. Nice job.

Thank you sir. 20 PSI out of the compressor was plenty for me to hear and see soapy bubbles from a spray bottle to find leaks

real life experience is very refreshing in a youtube full of 20 year olds that think they know everything. Thanks for this priceless knowledge.

Or you could use a male 1/4 flare by 1/4 male pipe and connect to your quick connect. Keep in mind, if your shop air is wet this is a very bad idea. Use nitrogen.

I love that the old school guys call the refrigerant freon it makes me smile :)

This was the quick method I was looking for. Thanks. Godspeed to you

I just did this exact thing on my Expedition and found my leak. Perfect trick - thanks for sharing!

I am from Russia and I just love this channel. I hope you will be better and better after the stroke. Keep moving and keep working. Wish you everything good.

Great as always thanks for sharing your knowledge

Great video and troubleshooting! Thank you for posting

Good morning family and thank you very much for the valuable information and for your time 🙏👍🏼👍🏼.

So simple I never would have thought of it. Took me all of 3 minutes to find my leak. Thank you soooo much

An absolute pleasure to listen to... thank you, SIR~

Very professional and clear. Thank you.

Smart guy you are mr. Thank you by you video and tricks about the AC.

To keep your air fitting from leaking, use a 1/4 flare to 1/4 pipe thread and connect that to the air hose quick connect (male or female, whatever you have handy will determine the 1/4 flare fitting)

This is exactly the information I needed. Thank you for sharing!

Thanks.... I always learn something

Great tricks as always thank you so much sir

Excellent video! Thank you!😀👍

Thank you for making this video!!!!🙇🏻‍♀️

Have always used nitrogen for testing ac as you can get the system up to operating pressure with the right regulator and fittings with no leaks from your test rig thend dish soap and water in spray bottle.With this setup I can find small holes in condensers and leaks around o rings, a very small leak over a long period will empty a system as well as a big one. And with nitrogen you are not adding extra water in to the system. But in pinch I can see where this is going to help . All you now is a crimp and your on the home run.

Good to see you again. Thank you for helping me with my AC

now that is a good tip or trick. I have a leak in my darango, now i know how to find. don't know if i have any kind of pressure, but will find out. if no pressure now i know what to do.. thank you so much. have a great day

Thank you for this brief and top notch presentation.

I bet a spray bottle with some soapy water would help too..😁

I dont know why I didnt think of this! Thank you!

Good explanation. I would also suggest to first bleed the shop air tank of any water in order to minimise suspended moisture in air put into systems. (All air compressors have a water bleed valve at the lowest part of the tank)

amazing educational video, keep it up!

Excellent! Thank you for the great video!

Love his work

I seen an older man on the thumbnail and said, "yep, that's the video im picking " 👍 great idea

Wonderful explanation. Great video as always.

Thanks for all your videos they are always on point all real

Now that is a fantastic idea! Thanks, Duane! 👍🏻 🍻

thank you sir for making this great video.

Thank you so much! I was able to find my leak right away with this method!! 😊

Thank you for another great video.

You sure saved me a bunch of time and money. Thank you sir!

Just what I was looking for! Your my kinda guy! Thank you sir!

Very good sir. I was trying to think of a way that check for a leak without charging with refrigerant/dye.

Excellent video…creative and cheap!

That's a good method for major leaks, but not for small leaks. Powerful car A/C compressors will easily pump way over 200PSI (300PSI on the high side on a 4th gen Z28 Camaro on a real hot summer day for instance ... think AZ desert "loco" day), and you need to be able to check such pressures. Most of shop air that I know go 120 - 150PSI max, I haven't ever seen one going 300PSI. I don't know ... nitrogen pressure test seams to be the accurate way to do the job, AND you don't further pollute the A/C system with air moisture if you're dealing with small leaks. You know of any shop air that goes 300PSI (brand, model) ??? By the way, you can weld together a 1/4" SAE adapter for A/C pressure testing. Anyway, nice video! 2 thumbs up!

Great video, good ole air trick👍

Thanks buddy. found out the evap was leaking using your trick with my compressor. Time to tear into the dash

Awesome video...i was wondering if a person could use shop air to find a leak

I hope ur around now, I just saw this video. it is a good idea, but a 1/4 flare fitting x 1/4 mpt adapter from the local HVAC store would be ideal to screw in the guage hose fitting, then you could put the air hose adapter to the male pipe thread and there will be no leaking then.

Very helpful video. Thank you Sir 👍

thanks,happy to see you well .

This in a great video! Thank you, sir.

Crack it’s in two pieces. Good trick I use it in the same manner just I add air directly to the gauges themselves. Great work God bless

Nice. Just what i needed. Thanks.

Great videos sir! Keep it up brother!

This will work, however keep in mind when I went to get my 608/609 license they told us in class if we do this you have to flush the system first because 134a and compressed air will cause an explosion, the slightest bit of 134a can, it's not grantee that it will, BUT it can cause an explosion. People be careful.