How To 'Top Off' Your AC System

Sometimes your AC system might not be working as good as it should. Sometimes this is due to a low system charge. In this video I walk you through the steps of topping off your AC system to get it to cool better.
Keep in mind the pressures in this video may not be the same as what you might see on your vehicle. The pressures are dependent on the system your working on, the relative temperature, and relative humidity.
*Note* This is not likely to work in all situations. Also, be sure and follow safe procedures when working with refrigerant.
The best place for answers to your automotive questions: www.ericthecarguy.com
Some of you may note a different cameraman. Don't worry, Brian is still working with me, he was just off when we shot this video.
Camera: Derek Sims
Thanks for watching!
Additional Information on Diagnosing HVAC problems: www.ericthecarguy.com/faq/sol...
Discussion about this video: www.ericthecarguy.com/kunena/...
Related videos
AC System basics: • AC System Basics - Eri...
AC Performance test: • AC Performance Test - ...
Finding and Repairing AC leaks: • How To Find and Repair...
Recharging AC systems: • How To Recharge an AC ...
Tools
Manifold Gauge Set: www.jbtoolsales.com/atd-tools...
Vent Thermometer: www.jbtoolsales.com/robinair-...
Safety Glasses: www.jbtoolsales.com/sas-safet...
**Answers to your automotive questions found here: www.ericthecarguy.com/faq
Social Network Links
Facebook: EricTheCarGu...
Twitter: / ericthecarguy
Google+: plus.google.com/1001951801966...
Instagram: / ericthecarguy
Information on Premium Membership: www.ericthecarguy.com/premium...
Stay Dirty
ETCG
Due to factors beyond the control of EricTheCarGuy, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. EricTheCarGuy assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. EricTheCarGuy recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of EricTheCarGuy, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained in this video is the sole responsibility of the user and not EricTheCarGuy.

[@MikesVlogss]

@EricTheCarGuy Here again in 2024, thank you for the famous A/C video on KZbin! I use this video as a refresher course before i start doing Refills on customers cars here in Yucaipa California! This is my 7th year that i keep coming back to reference your helpful tips & tricks! Thank you....

[@Carguyforlife]

You and me both! I appreciate that he made a detailed video about what to do. Seems like most videos out there are either "hey here is how you add freon with this can from the auto parts store with a gauge already on it!" ... or ... "A/C work is super complex and only trained professionals should ever perform any work on an A/C system."

[@gvxclassics]

I might add that our 05 Accord Hybrid just had an issue with poor cooling. I diagnosed as low refrigerant and took it to Honda for a full check out. They agreed with diagnosis, but, also changed the two Schrader valves under warranty.. So after 15 years, Honda is still standing behind their product... and the A/C works great again. Thanks Eric, Thanks Honda.

[@gquach]

I've watched so many ac instructional vids and this one is one of the most well explained instructions. Thanks Eric!

[@lazybbones]

I love the content, as well as how the video is constructed: A+! No annoying background music, no offensive language, steady video shooting, very well explained, and you can talk in complete sentences. You don't talk "below" me, and you don't talk "above" me. This is all true for most of what is here on youtube, but certainly not all. Very good job, and you saved me time and money!

[@tw1081]

Hi Eric, Nice video on A.C. top off but I noticed one glitch--- perhaps. I have been in the HVAC business for >30 years and remember my first boss who taught me telling me about liquid vs gas recharge. Whether it is a cheap can or the big jug the valve pick-up stem is on top just below the valve. When the container is right side up you get a "gas" and when upside down you get a "liquid" freon coming out. For speeding up a full recharge on an empty and evacuated system with the jug on a scale, you can start with liquid until 75% full and finish with gas. For topping off a system, you want to keep the can right side up and use only a gas which the compressor can compress. If you shoot in liquid and it gets on top the compressor piston it explodes, throws a rod, cracks the piston, cracks the valves, or cracks the compressor casing. I know--it happened to me when a used car I bought was cooling poorly and the seller offered to top it off with R-12. He had the can upside down as we watched the pressures and temperatures improve. I told him he should have the can right side up but he said, "I think I know a little bit more than you about recharging AC systems Tom". He was 20 years my senior so there was no convincing him. Right after he said that there was a loud "bang" and the compressor spun freely with no compression. He had broken the rod and cracked the compressor case in multiple places. He then realized what I was trying to tell him. I always use gas with the can right side up and go much slower on the low side pressure when adding it. It is way safer and much more fool proof for a newbie keeping the can right side up. I also like to watch the sight glass on the vehicle until it is full with no bubbles for a sign the system is full. Other than those nit picks, you nailed it!!!! Tom

[@coolramone]

What should the running pressures be on the R134a refrigerant in a vehicle? Vapor line 40 psi and Liquid line 200 to 220 psi? I read that the static pressure should be 90 to 100 psi.

[@kmlumd44]

​@@coolramoneyou can google r134 gauge readings or something like that and there is low side and high side ranges given multiple outdoor temperatures.

[@Garagejunky09]

Would like to say, 6yrs ago u saved me 2k on fixing my ac system on an 09 accord, Thank you!. 6yrs later...here I am again. Glad to see u doing alright 👍

[@stevelanday3909]

Eric, i've watched 20 or so of these AC videos, yours by far is the most informative and helpful. Nice Job, and thank you!

[@DrewGarage]

Eric, I have always appreciated your channel, I am a semi professional myself… We own a small car dealership and I do all of our work… I loved this video because it literally answered all of my questions in a relatively short time, and I didn’t feel like anything was left out or unnecessarily mentioned. Even your notes at the very end… I had that happen with a stuck Schrader valve, blipped it and it was fine. You covering details like that is why this is a great channel!

[@jamminjimmy3848]

Thank you eric!!! Got my AC back to cold. Im out of work right now, and sure did save my sweaty bacon by you showing us how to do this ourselves!! great video!

[@mikefruge8589]

I have the gauges, but harbor freight instructions were not very thorough. You did a very good job of explaining how the process works. Thank you!

[@sleepingwiththedog]

I watched your videos in the past, and returned for 2 separate vehicles for today for a refresher. Like the other person said, great video content with no bologna. Your a natural at teaching, great job Eric

[@jamesjordan7460]

This is the best Auto AC channel I have seen on YT! I just bought me new gauges to take the guess work out of adding freon 134A

[@nissandudeful]

Heya Eric - Youve sure come along well and progressed nicely with your instructionals. This is prob. the best "How to" yet. Thank you for the great job ! Dave.

[@johnl3502]

Absolutely A+, Thank you Eric, so well explained! You made it simple and easy. Exemplary video, compared to other's efforts!

[@CraigArndt]

I tried doing this last year and I wasn’t sure what I was doing. I watched this and understood my gauges better. I just got another 10°s cooler in my Jeep. 80° day and I’m at 49-50° out the vents. Perfect, thank you Eric, saved me a lot of money.

[@myisonu4639]

Once again Awesome video. I have been following your channel for more than a year and truly appreciate the knowledge your willing to share with us garage mechanics. I have saved myself and family unnecessary spending by doing the job myself.

[@michaelw6277]

Man, thanks for this. I have a nearly 8 year old car with AC that performs well enough until the peak summer months. I have a manifold gauge set and a couple of small cans of refrigerant, but finding this clear of a how-to for just adding a small amount, as opposed to charging an empty system, has been difficult.

[@kylefowler5082]

This is a great video on how to use the manifold gauge set. I learned alot! I would add that it's important to get your factory service manual and see what the high/low pressures are supposed to be at a given RPM and temperature. For example the FSM says on my Ram to check the gauges at 1000 RPM. Also the high and low pressure chart is way different from the generic suggestions found online

[@willarddickerson921]

I have looked at many of your videos and this one before, but the last time that I looked at this video, about three years ago, I missed a few important things that you described. I can't describe how much I appreciate you sharing these things with me. It's been ruff, and people like you have made it possible for me to survive. I truly apologize for not taking better notes in the past. This is a reminder why ChrisFix mentioned you in one of his videos. Three years ago, I was successful in installing a new AC system on my previous vehicle and adding a charge to my lady friend's car three years ago. Her vehicle's AC is still running cold. I did use gauges and a pump that I purchased from Harbor Freight. I would recommend to oil the O-rings with PAG oil, and DO NOT over-tighten the connectors, or they will leak.

[@AB-kv8ky]

Good job. Well done, sir. I dont claim to know what Im doing. People seem to have this unearned confidence in me but I find that I usually know just enough to get myself into trouble. Nothing bad happened, thanks!

[@bronzedoor7092]

Excellent video Eric. I used to supervise a large farming operation and we did this kind of work on a weekly basis.👍👍

[@TechTravelBeyond]

Thank You! This was filmed and edited so well. Excellent instructions, and like being in a class!

[@trevorbusse7083]

This was incredible helpful and concise enough to keep me on track. Thanks for keeping it simplified and well worded!

[@Gmt400]

Every time I go to get repair information, you have a video. I have used your information more than you know. I want to give a big thank you. I have been watching for years and thought you would like some nice comments and a big thank you.

[@pzm958]

Want to acknowledge you for this timeless tutorial on this process - have referred to this a couple of time and it is spot on!! Your willingness to share your expert knowledge is so very much appreciated!!

[@21cElectronicsMaster]

This is one of the only video's I've found that gets Straight to the Point! No Bias, just the Real Advice. Thank's Eric!

[@kmlumd44]

I was up in the air as to whether evacuate and refill my 2 used cars since i rented all this equipment to do a compressor condenser replacement. I had decided not to, but i was aware my ac's werent as cold as they could be. After watching this video im convinced that I'll use this method on both of the used cars tomorrow. Thank you.

[@ajibaby2217]

This is one of the best videos on auto ac explained in an easy to understand manner which also includes very important details. Nicely done.

[@66lwmorgan]

One of the best tutorials I've seen on charging the AC system, thank you Car Guy, appreciate it.

[@rjkerb08]

O

[@davidsanderson5466]

Old Scotty Kilmer says to only put in Refrigerant gas because the Liquid could hurt the compressor. Thoughts? Great video besides.

[@knighthawk86855]

I did a complete o-ring, and seal replacement on my large dodge conversion van b1500 2000.....with rear ac, had to pull a vacuum on the system, cause the place I took it to for head gaskets did a wonderful job on the engine, almost completely rebuilt it, clean out everything, very good job, but they never recharged the AC system, guess they forgot, well I did it all, replaced everything in the front, including rad, all lines everypart of the AC system, just did the rear, and lines today, recharged it, and got that sucker down to 41°F.....super chilly now, and I used your video to help with part of the recharge, thank you.

[@waltp3373]

Blipping the Schrader valve was a great tip. The last A/C system I rebuilt had a leak in the Schrader valve. I replaced both valves which fixed the problem but blipping them might have saved me more work and some lost refrigerant.

[@silasmarner7586]

Nice! Crystal clear demonstration/explanation..

[@bcharper21]

Thanks for showing us the “next level” of A/C work…will come in very handy in the TX heat!

[@trappistachel]

next level mama, next level

[@rednkfn]

Literally the only real video of this on KZbin.

[@samuelseager6785]

Such a good video. All needed facts and no unnecessary narration, said at a good speed and clearly spoken, with great video showing everything I need.

[@scottspitler1443]

Excellent step-by-step tutorial. Thank you, Eric.

[@danielfloyd396]

I found this video very useful. Thanks for taking the time Eric. Most of the guys criticizing the vid and strongly advising against DIY ac work are shop mechanics or HVAC guys. Obviously it would be a conflict of interest for you to encourage us to do our own work when you can charge us an arm and a leg to do it for us. On a personal note, I replaced the ac compressor, accumulator, and orfice tube on my car about 5 years ago and the AC still blows ice cold. Thus, I highly recommend doing your own work and avoiding high shop costs whenever possible. Of course, this doesn't mean try rebuilding your own transmission yourself lol.

[@malikoza]

You are the best out there. Fantastic teacher. Well done. I needed that information and NO one has done that on the internet. Many thanks!

[@gehancheung1505]

Thanks Eric for all your helpful videos. Really appreciate how you describe each component, its best practices, and tips to address common issues (like blipping the shrader valves to clear any debris; after charging, allowing the AC system to draw in residual 134a in the charge hose).

[@godfreyrinoona1361]

after watching this vedio im now an AC technician .Thank you

[@joeclarke9782]

Thanks, Eric. Just what I needed with temps regularly over 90 here in Ohio.

[@jimmietullis2264]

Very thorough step-by-step instructions. You spoke clearly and easy to understand. Thanks!!

[@mattrobertson9468]

Great video. Lots of good info, especially the tip on purging the charge hose. Makes complete sense, but I hadn't thought about that at all.

[@andrewhernand7469]

I appreciate your step by step explanation how it should end up or look like to what might go wrong along the way and what to expect keep up the good work excellent diy 🇺🇸

[@tdoanntap]

Very helpful and informative about charging and setting the A/C system. For that reason, I just subscribed to your channel. Thanks and keep up the good work Eric!

[@ScottDLR]

This is super timely and helpful for me. Thanks a bunch for making the vid!

[@andrewbalfour7130]

Eric you educated me in a complex system. Your video made a whole lot of sense now. I only wish I had found and viewed it before I took my van to the dealership

[@alanh8664]

I've seen about a dozen of these, yours is the best. Thank you!

[@IRaceFormula]

Love your videos, Eric. Wanted to add some important notes to your video that might be helpful. 1. A/C Pro's "Sealant Leak" destroys expensive A/C machines like RobinAir, etc. This is why we use a sealant leak detector before we start our evacuation and recharge on any A/C service. If sealant leak is detected, we deny the customer. 2. If the customer or shop has it available, after our sealant test, we use nitrogen to pressure test the system for leaks. Sometimes the expensive A/C machines claim that the system has passed the vacuum test, when it really didn't. A nitrogen pressure test covers that base. 3. It probably depends state to state, but I know where I lived (Idaho and Utah,) you need a Mac's Certification to legally buy refrigerant. Thanks for your videos!

[@DayClanTribe]

Good to know about the Sealant Leak damage potential. As far as leak test, a vacuum is never the way to test for leaks, only nitrogen positive pressure. 134a is available to anyone here off the shelf at most stores in small quantities.

[@testuser3167]

R134a is (still) legal for sale to anyone in small quantities per federal guidelines, but states can be more restrictive, although the EPA is trying hard to change that. On the premise that they will eventually do so, getting an EPA 609 certification is pretty easy, and can be done with an online (open book) test for $20-$25. I'd like to know more about the sealant leak detector, I've never heard of such, and I'm currently (casually) shopping for my first recovery machine, so it would be helpful to know what to look for, as I'd hate to have it ruined by someone else's gunk!

[@crawfordi4506]

Your info was and is right on! I understood everything. I watch most all your videos. Some are not needed, but very knowledgeable. Good going. Stay safe and take care!

[@KarisaLea]

Love all the detail that you put in the video. Just what I need and was looking for. Great video!

[@laurijorgenson6683]

You rock Eric. Thanks so much for your thoughtful explanation of how to do this successfully. I sure appreciate it.

[@danieldyer4354]

Thank you for making this video Eric, love this video ...your very detailed and thorough and I appreciate that because I don't know what I'm doing 100 percent so this really helped me.

[@PJ-ee5mc]

Eric, this is a fantastic video! Thank you for sharing your knowledge and experience as I tackle the AC in my C6 Corvette tomorrow morning. Keep up the great work.

[@bestshrooms3283]

Thanks so much for your pioneering videos. You were the only detailed trustworthy source for these videos many years ago. Due to your knowledge I started down the road of doing my own auto work. And saving big money from staying away from Tuffy. Thanks

[@dwtees]

You work like a professional tech Eric. You charge AC systems exactly like I do. I'm sometimes criticized for turning the tank upside down and charging with liquid refrigerant. I've be charging systems like this the same as you do all my life without one single problem. I'm a recertified ASE master L-1 tech with over 45 years in the business. I own a repair shop in the Houston heights. Good information. You make great car repair video's.

[@kylekoster3432]

A message for all of the "ASE certified master techs" watching a video about how to top off refrigerant, the orientation of the bottle is completely irrelevant. The state of the refrigerant is determined by a few things first pressure second temperature. If you think the orientation of the bottle changes the state of the refrigerant from gas to liquid you have a fundamental misunderstanding of how substances change state and you should avoid telling actual professionals how to do their job because you've made yourself look like a moron in the process. Also consider that the hoses travel UP AND THEN DOWN, this still doesn't matter at all in reality but even in the scope of your ignorant view would still debunk what you're saying. "I copy pasted this so it's not really directed at you but it confirms what you're saying about the orientation of the bottle being irrelevant"

[@CoCoSWISS1]

The orientation of the bottle is CRITICAL unless it is 100% full of liquid. As liquid is removed then its level goes down and above it you have a combination of gas and a vacuum, which is not what you want to pull into your system. Liquids are always heavier than their gas counterpart and gravity always sucks. The reason the height of the bottle doesn't matter is because the system pulls the liquid freon from its container (or freon gas, in your case). The same thing is true with filling a lighter with Butane. To get the butane liquid to flow you have to turn the bottle upside down. Propane is different because you actually want to pull out only the gas and not the liquid.

[@CoCoSWISS1]

@@kylekoster3432 The orientation of the bottle is CRITICAL unless it is 100% full of liquid. As liquid is removed then its level goes down and above it you have a combination of gas and a vacuum, which is not what you want to pull into your system. Liquids are always heavier than their gas counterpart and gravity always sucks. The reason the height of the bottle doesn't matter is because the system pulls the liquid freon from its container (or freon gas, in your case). The same thing is true with filling a lighter with Butane. To get the butane liquid to flow you have to turn the bottle upside down. Propane is different because you actually want to pull out only the gas and not the liquid.

[@trevorjudd516]

Hey Eric, I've found the best way to remove gauge lines is: 1/ Turn cylinder valve off but leave line connected 2/ Turn off discharge line but leave connected. 3/Open suction valve to draw in refrigerant from both discharge AND service line. 4/ When system equalizes turn off all valves and remove. You put the excess refrigerant back into the system and not the environment! Regards, The Guru of Cool Australia

[@MsLincos]

Hi Trevor, I have no experience with car AC systems but, can you tell me why nobody push the air out of the blue line before filling the system? Thanks!

[@roysimpson2126]

@@MsLincos You should. Very important. I'm guessing Eric forgot to mention/show that. I'm sure he knows.

[@Toddtoddy78]

You da man! Clear, concise and thorough. You made it a jiffy for me to make my old worktruck luxurious again.

[@brunosbay7671]

Very clear instruction, knowing more than I did prior. Easy listening thanks

[@pedlpower]

Excellent vid! I've worked on R12 systems long ago and I needed to know what the pressures should be on R134A. Thank you.

[@goclunker]

Great video, used it as a guideline. It would be great to add a link to a chart for the pressures vs temp vs humidity. Charged one car today. Works fantastic, getting 40F driving, 230 High, 48 low

[@williamserver4332]

Great video. I do HVAC in homes but had questions about cars. You answered all of them.

[@ivanmartinezgarcia5973]

Excellent. This is the information I was looking for. Most other videos only explain in regards to how to do the complete recharge with the vacuum pump and measuring the amount of refrigerant using a scale.

[@rhkips]

A nicely detailed and very comprehensive video! There's a lot of misinformation out there, so it's nice to see something honest and accurate for a change!

[@jsardelli7322]

F I’ll i ut

[@jdlane5136]

Eric is one of the best mechanics on youtube. Thanks for the info.

[@carpenter1211]

Wow great video, answer alot of my questions I had, still have alot to learn but guys like you who take the time to do these sure helps alot.

[@Clearanceman2]

Thanks, I fixed the leak and filled the AC in my one car but topping off is different. Appreciate the video. You can borrow gauges and even a vacuum pump from Auto Zone.

[@girohead]

Borrowed mine from O'reilly.

[@carlos-kx4sn]

You always make awesome and helpful videos buddy. Couldn't done it any better

[@cornwellteam]

Js

[@dadtype2339]

I'm a professional and I hate working on AC...HVAc in total but especially AC. Lol, I have fixed it, I absolutely can and have, but I also absolutely hate it. Been working on cars for 40 years so I don't think that's ever going to get better lol. Always a thumbs up EC, just helping to keep the channel up.

[@kaitlyndavis2748]

Nothing feels better than cold AC. Just got mine back up and running! Thank you!

[@Gr8thxAlot]

I used this method, worked great!

[@JT-qf4it]

I always purge the low and high side hoses after I hook them to the system to get rid of any air that may be in them before adding any refrigerant to system.

[@Roboticdoughbull3k]

Does that mean you basically connect the low and high sides to the vehicle and then at the gauge ends of the low and high, you open the valves to let some pressure push the air out and then close the valves? Or are you meaning purge somehow from the charging ends of the hoses where refrigerant is added, allowing it to escape the vehicle side before fully seating the low and high sides to the connection ports? Thanks

[@JT-qf4it]

@@Roboticdoughbull3k After hooking hoses to car, I crack open the low and high side hose at the a/c gauge manifold to purge a small amount of gas which pushes out air in hose.

[@Roboticdoughbull3k]

@@JT-qf4it I gotcha now, I figured but just wanted to check. I got a set last year and am about to start helping out the family vehicle fleet, little things like that are good to know. Much appreciated, thank you!

[@caddyguy5369]

I'd connect the high side the purge from high to charge hose. Then hook up charge hose or put back on holder. Then purge high to low. Then hook up low side. Then you're purging possible contaminants and air from the manifold itself.

[@wingerrrrrrrrr]

In addition to the purging, I usually hook up the high side hose to the car before turning on the AC so it's not under high pressure, and hook up the low side with it running, so the valve is at the lowest pressure. After it's all done and when disconnecting the hoses, remove the low side first while the compressor is running, and remove the high side last after shutting down the car, and allowing the pressure to equalize and drop back down. That helps reduce the bit of refrigerant loss from opening the connections under pressure.

[@Greybuiltracing]

Erick ! It’s been a while since I’ve watched your videos. Glad to see you are still grinding . Ty

[@TheCopilot91]

Eric, this was super helpful. I've never topped off an A/C before and now my A/C blows super cold. Thanks!

[@KarasCyborg]

@5:19, so a newbie hooks up a pressure can and see's 80 psi, they are going to think there is too much refrigerant in the system, that they overcharged it because when they look at the side of the can it's going to say low side 32 psi, high side 150 psi when the temperature ambient is 85deg. I think the important thing to stress at this point is that in order for an accurate reading to take place on the low and the high side is that the compressor must be running, the clutch should be engaged and you should physically see the compressor clutch assembly spinning and one line coming from the compressor will be hot and one will be cold, maybe even developing frost. If it's not, STOP, nothing here will make sense. There might be a low side pressure switch that is stopping the compressor clutch from engaging or some other electrical failure. I've seen those power probes that can force the compressor to run by stimulating the + (red/hot) of the of the compressor clutch assembly to help troubleshoot is it a refrigerant/compressor/clutch issue or is it an electrical issue.

[@colebennett6424]

If you DO have too much refrigerant in your system, how do get rid of it?

[@wingerrrrrrrrr]

@@colebennett6424 the official way is to use a recovery machine to remove the refrigerant. The diy way is to release it to the atmosphere. Just make sure you're monitoring the pressure so you don't go overboard and have to add back again afterwards. 😭

[@DustinB855]

Eric!!! I had a 1993 Acura vigor come through my dealer that would of made u jealous. 60k miles and no rust looked brand new

[@fishfire_2999]

I remember those 5 cylinder.

[@JoeRCV]

Thank you Eric, straightforward video for the A/C to DYI guy

[@indian4556]

Hi Eric, love your your youtube videos, the are so informative i have been a fan over 4 years and i just love your work. Keep it up.

[@RockyXTV]

I did a video on how to top off your ac system about the same time as this one, well I was shooting it and posted it a little later. I did a beginners version using only the can and gauge you get at the auto parts store. The video was inspired by an older lady at the auto parts store asking where to take the refrigerant that she just bought to have it put in her vehicle. I thought to myself "I wonder how many people actually buy these cans and then pay someone to put it in" I really like making videos that show people that they can actually work on their own cars and save some money. Great video! I can only hope that my channel will get even 10% as successful as yours.

[@exceptionalchris]

I have no pressure when I connect my gauges. That means I have a break in the system?

[@rvamotorsports4379]

Chris that’s means your system is empty

[@Chaddz3]

Depending on the type of AC system you have, these cans with the built in gauge are worthless.. you can get them to work ok on a fixed oriface tube system.. but a newer system with a TX valve that gauge wont be accurate as the TX Valve throttles the refrigerant on the low side depending on the amount of superheat on the vapor line going to the compressor.. It is very easy to overcharge a TXV system with these can setups since the pressure doesn't change much if at all on the low side. These systems are monitored on the high pressure side when charging.

[@beatricejeanfreau6402]

A "rule of thumb" is to multiply the ambient temp (Fahrenheit) by 2.5 to determine what the high pressure side should be. If it was 95 degrees the high side should be running about 235 psi. Not exact but certainly better than just shooting something in there while only measuring the low side.

[@tscrain8277]

Is that basically on ALL car AC systems, or are some higher, or lower??

[@tylerfabish5578]

@@tscrain8277 all.

[@Matthias53787]

If that's a good rule of thumb, then why do they have charts?

[@tylerfabish5578]

@@Matthias53787 charts are the right way to do it. A rule of thumb is just a rough idea. Example: on a customers AC i am looking for around 70 psi low side on an r-22 system. Thats a rule of thumb. But it can be higher or lower depending on other factors. It gives me a starting point

[@jasonschell9860]

Always helpful. I just recommend people do their research to get the basics down. Understanding what Freon does and having the right tools makes all the difference in the world

[@andrewbalfour7130]

I purchased an AC refill kit. The instructions sucked. I watched your video and it all makes sense now. This is by far the best AC video out there. You should be the educational video for all those DIY AC recharge kits.

[@davidsullivan7867]

Over the years I have trusted, respected and used much the info you've put out regarding Honda's. Got to question putting liquid refrigerant on the gas side? Even if for only a couple of seconds...isn't that a bad practice?

[@coldfinger459sub0]

I'm glad to see you properly recommend Pure refrigerant only with no additives this is a must especially on the new smaller capacity systems. But unfortunately I would never recommend somebody inexperienced to use the liquid side of the refrigerant especially on systems where the low side service port is directly attached to the compressor or even close to the compressor without the protection of being on the accumulator or before the accumulator to separate the liquid . This is how a lot of my customers burn up compressors trying to do it themselves. Or they do so much unseen damage by completely solvent washing all the lubricant from the compressor just in that few seconds of charging with liquid it scores the surfaces in the compressor fails a few months later once the damage is done it progresses and again the The customers coming in for a new compressor condenser flushing out the system for a little bit of damage for temporary cooling of what they thought was correct.

[@ericthecarguy]

I have yet to have that problem and I've been charging this way for many years.

[@harrismaynord871]

Eric, you make great videos. But when you're advising DIYers like me, why not tell us the BEST practice that has the fewest potential problems (even if only theoretical). In this case, that clearly is to take a few minutes longer and charge it with gas.

[@Benjamin-tx6vv]

you get lucky until you dont. really, charge with 134a with bottle up when charging on low side. Btw, that sigh glass shows liquid entering the manifold...which i bet doesnt flash fully by the time it reaches the compressor.

[@kylekoster3432]

@@Benjamin-tx6vv A message for all of the "ASE certified master techs" watching a video about how to top off refrigerant, the orientation of the bottle is completely irrelevant. The state of the refrigerant is determined by a few things first pressure second temperature. If you think the orientation of the bottle changes the state of the refrigerant from gas to liquid you have a fundamental misunderstanding of how substances change state and you should avoid telling actual professionals how to do their job because you've made yourself look like a moron in the process. Also consider that the hoses travel UP AND THEN DOWN, this still doesn't matter at all in reality but even in the scope of your ignorant view would still debunk what you're saying.

[@harlyfarfan8798]

Thank you Erick for all your help and a great way to teach how to do it right

[@knottreel]

I really appreciate you doing this video. Most channels only show AC charges when it is empty, where they pull a vacuum and weigh the amount that goes back in. I was unsure what you did if you already had some refrigerant in a working system.

[@tmst2199]

Here's a chart I copied off an A/C website. As you can see, ambient temperature strongly correlates to desired high- and low-side pressures. According to this, Eric's low-side pressure should be 50-55 PSI since it's 95 degrees F outside. Please note that the low-side pressure should never exceed 55 psi w/ the compressor running: 65°F (18°C) 25-35 psi 135-155 psi 70°F (21°C) 35-40 psi 145-160 psi 75°F (24°C) 35-40 psi 150-170 psi 80°F (27°C) 40-50 psi 175-210 psi 85°F (29°C) 45-55 psi 225-250 psi 90°F (32°C) 45-55 psi 250-270 psi 95°F (35°C) 50-55 psi 275-300 psi 100°F (38°C) 50-55 psi 315-325 psi 105°F (41°C) 50-55 psi 330-335 psi 110°F (43°C) 50-55 psi 340-345 psi

[@socrates2706]

Are these values when the engine is idling?

[@izzydizzy1115]

Eric, I always enjoy your videos and approach. I'm surprised you are charging the system with the refrigerant bottle upside down. I am a retired auto tech, GM trained and was always taught to charge as a gas (right side up) vs liquid (upside down) I know it works obviously from your video, but you're feeding the compressor a liquid charge. Compressors pump refrigerant in a gaseous state. Just my 2 cents.

[@TheLarryBrown]

Everyone is belaboring this point, but it can be summed up like this: It can be done either way, but unless you think you know exactly the pros and cons, always charge with the can right side up, charging with a gas. Never charge with the can upside down, trying to charge with a liquid.The only reason to charge upside down is to make faster work of it, and if you're just trying to get the job done on your own car you don't mind taking a few extra minutes. If you see your A/C guy charging upside down, he's reckless. Move on to another guy.

[@deanstuder1775]

Agree with all you stated but wish to add a bit more. You can not compress a liquid, this is the basics of hydraulics. So why send a liquid in to an air compressor. Chances ate increased of causing premature failure of your compressor. It may work, as Erik has demonstrated. But its not how the compressor ordinarily works. Check out any air conditioning theory of operation. Gas is compressed into a gas. Both sides are gas. High side obviously more pressure than the low side but no liquid near the compressor ever, until beyond the centers of the evaporator or condenser heat exchangers . I am amazed this hasn't caused more troubles for you Erik.

[@JAYJAYJAY53]

@@deanstuder1775 maybe because he just add tiny amounts quickly?

[@rhoodj]

This is a good point. I heard that before. I was surprised 😮 too.🤜🤛

[@sfitz-rp4du]

Thank you Eric for very good video including the tip on seating the schroeder valves at end of job. As an fyi to your viewers, these gauges can be rented for free from some of the auto part chain stores. I completely replaced system last year. Not blowing cold now. I'm thinking slow leak from schoeder.

[@paulwharton1850]

Outstanding video - helped answer a lot of questions - Many thanks!

[@jameschrisdavis]

12:10 I always learn something new watching your videos. Thanks!

[@JacobEcret]

I agree on this, I’m going to do this next time

[@misterspock3561]

Hi Eric, ANOTHER great and helpful video. I have been doing most of my car stuff myself for the last 40 years or so. If I get into a jam or need to know how to do something I seek you out. Many great videos. I have been doing my own AC charging and repair for about 10 years now and with great results. Usually I evacuate the system and charge it up after giving it time to see if there are any leaks. Basically I start from scratch. My moms old Infiniti I30 always had great AC, usually around 38 at best on the highway. I'm using 2 types of thermometers as sort of a control, one digital and one analog. Lately, I noticed the car was hanging out around 50 degrees. So instead of evacuating the system and start from scratch, I always wondered how do you know just how much to add without starting from scratch. Your video explained this well. However, I do have a question on this video. You stated you "charge" the system with the 30 pound container of R134a upside down, for liquid. I was always told that doing this can mess up the compressor and was told the can should be right side up for gas. Can you please let me know the facts on this? I also use the proper gauges and the 30 pound can along with a good scale. THANKS AGAIN!! Have a good weekend and be safe.

[@testuser3167]

If you're charging slowly enough and in small quantities at a time, the liquid will have time to boil into gas before it can adversely impact your compressor because well, the pressure is low enough to boil it. If you're starting from scratch (and the engine is off), you can also charge liquid on the low side (use a scale to know how much you're putting in!), but that tends to work best on fixed orifice tube systems, not on TXVs, because a fixed orifice tube system will tend to equalize much better when the compressor is off. Either way, check the specs for the system and don't overcharge it. I've also graduated to a 4-hose manifold with valves on all of them, so that I don't have to disconnect the tank to pull a vacuum, and I wish I'd done it a long time ago...

[@olid.7568]

Thank you so much for all that information Eric!!!! 👍👍 Love your videos

[@jdubya54]

Thanks buddy. Excellent video as usual. You always hit the major and minor points

[@spelunkerd]

You made many excellent points, Eric. Here in Canada, freon is not sold to consumers or even mechanics without proof of AC certification. I believe that's done to protect our global atmosphere. The only coolant available from retail stores are propane derivatives, which will contaminate a 134a system with a different coolant. I don't know if that makes a difference but it may cause recycling issues when one goes to legally evacuate the system.

[@Darksyne]

It's also illegal to "top off" the AC system to fix the problem, it needs to be evacuated and the leak must be fixed before it's refilled with 134A. This is why every one here cringes when their AC stops working because you're guaranteed to spend hundreds just to fix it. And those refrigerant substitutes may even make the problem worse by contaminating your whole A/C system or damage the compressor.

[@williamfigueroa6662]

Any body know the different between 134 R refrigerant from Walmart, about $5.00 a can and other more specific from the auto parts, do they work the same ?

[@Chaddz3]

the $5 cans are the ones you want. they are pure HFC-134a and do not have the oil and additives in it. In the case of AC, cheaper cans are the better ones.

[@JettaRedIII]

Chaddz3 got it right. And, oh yeah, it's only $5.

[@aderaw849]

www Sax

[@larryboy4905]

Don’t forget to purge the hoses once you make a connection!

[@robertodebeers2551]

Good Job, Eric. I'll have to watch this several times, but I think your info will get me there!

[@davewolf8869]

If you get the Harbor Freight gauge set, the little knobs on the quick connect adapters are reverse threads, tighten them to open, loosen them to close. They cleverly hid this fact in the manual, and on the knobs themselves. For those of us who just assume, we may be outsmarted for a bit until we figure it out. FYI I LOVE my HF gauge set, they are sealed very well, they can hold pressure for a long time, disconnected and turned off, meaning the seals are good and high quality, with the 20 percent off, you can get them new for a little over 50 bucks out the door. Worth it :)

[@guygoodine5255]

Great video. You can certainly tell when the "teacher" knows what he or she is teaching. Thanks!