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I have been in the auto A/ C business for 48 years the use of a/c Dye is the best way because 75 percent of the leaks in auto A/c is intermittent due to expansion and contraction of all the aluminum parts and all the hot exhaust and water temperature repaid change I have the best sniffers that you can buy and use it first but most of the time we have to install a/c dye and bring it back at a later date and let it cool down and take all the plastic covers off put it on the lift and find the dye . We repair several hundred A/C jobs a season that is all we do

Thank you for CLEARLY EXPLAINING how recirculation and ambient temperature affect the pressure reading on the manifold gauges! The chart that you share at 2 minutes is a valuable resource that will be very helpful. Those areas had me a little confused until I watched your video.

I've been doing HVAC for 8 + years now. Car HVAC systems used to come pre-charged with dye. So yeah, dye is designed to be in the system. Dye is one of the best and easiest ways to find the leak. It mixes with the refrigerant oil and is A-OK to be in the system

I used this method minus the scale for my '07 BMW a few years ago and it's been working well ever since.

All car compressors are designed to leak a small amount of refrigerant to keep the outer seal pliable. Adding several oz every few years is not out of the ordinary. Also, good mention on checking condenser’s coils for blockage. Many times on very high mileage vehicles (200k +) the condenser’s coil fins are smashed closed. This will cause the high (liquid) side pressure & temp to run much higher than normal. May need a condenser replacement or lots of patience in straightening the fins to allow proper air flow/ heat transfer when high pressures/ temps seen on liquid side.

I was going crazy trying to find out why my high side was so high that the safety valve in the compressor was releasing refrigerant. I replaced expansion valve, condenser with no luck. I was about the give up until I decided to check the radiator fan. Turns out I replaced the fan a couple months ago and never checked the direction of the airflow. It was reversed so it was blowing through the radiator then the hot air was hitting the condenser which was heating up the refrigerant and causing super high pressures. A reversed radiator fan can cause high side pressures to be insane. A simple wire swap fixed the issue.

WELL DONE! Car Guys should watch this just to refresh their memory. Save this video to watch, the only thing I would add is to use goggles when working on the AC.

Thanks for clarifying the ambient temperature. Most videos say the pressure should be between 25 and 30 on the low side when recharging and about 190 on the high side and they don't say anything about the ambient temperature. The temperature here was about 102 degrees and my pressures were high around 40 for the low and 210 for the high but I had barely put any from a 12 oz can. It was still not blowing cold air. I put in some more and it started blowing cold air now my high is around 250 and the low still around 40. I will check it at a lower temperature later to see if it has a lower pressure. I was afraid it was too high. Maybe it needs some more.

Handy to have that chart available and explained!

Great video as usual....FYI not only do the automotive quick disconnects make it easy to connect, they usually have open/close valves right on the quick connect hose fittings so you don't actually depress the schrader valve until you turn the knob in after your connected...

Nice work Ben, I've done my research, did everything by the book and had fantastic results, even after replacing components like an evaporator, (NO easy task in today's cars). I use all OEM parts, proper oil and amount, system evacuation and such. I also had no R134A to reclaim so that wasn't an issue. I even have a scale to measure the refrigerant. One thing I noticed on your setup, looks like you did a liquid charge vs a gas charge, when is one desirable over the other? I'm also with you on the sniffer over the dye.

Automobile air conditioning systems operate as medium temperature refrigeration systems. You should have around 22 pounds of pressure which would give you about 25° of saturated temperature of 134 the ambient temperature only equates to the pressure temperature of the refrigerant. At 85° outside we would have about 95psig of pressure in the refrigerant bottle. That ambient pressure does not equate in the automotive system because you're not measuring subcooling nor superheat. An expansion valve is not the same as a TXV capillary device nor a piston. I'm no wizard, but my 16 year old truck puts out 40° out of the vents

When Ben Speaks, I LISTEN 👍

Use a thermometer at the vents, add very small amounts of refrigerant. One or two ounces at a time.

All compressor will leak at shaft seal. Always add a PAG oil charge (walmart) especially if leak is low and leaking oil too, without oil compressor will fail. If you need to add 12oz a year system can last indefinitely. To fix a leak and evac system diy'er doesn't have equipment and more parts may have to be changed also.

Great video, I would like to see more car stuff, ie finding leaks and repair.

If you're going to use the pressure/ambient temperature charts (or scale on gauges) beside turning OFF recirc' you should use a piece of cardboard or similar to block engine heat airflow from being pulled into the air box and across the evaporator. That means BOTH sides of the cowl vents need to be blocked from sucking hot condenser and radiator air and blowing it across the evaporator.

When testing the car take the temperature close to the Condensor. Ijust because it 75 degrees out doesn't mean the fan is Circulating 75 degree are. It's likely warmer. The other option is doing it when it's windy or use fans to move hot air away from the condenser. Oh and I know with R134a prices going up don't use propane. I yes it works better, but is flammable and you need a lot less and you would have to accidentally vent all the air to the atmosphere.

My life used to be so simple. I never thought about air conditioning at all for decades in western Oregon and western Washington. I hardly thought about heaters, or ventilation. I’d sleep outside even in winter sometimes. As kids we roamed freely. Then I lived in a van with no heater, water, etc. Now this crap is all I think about lolz. It’s good brain exercise I guess. But there sure a lot of crap to spend ones money on. I used to spend a lot more time going out exploring the woods and fishing. Now it’s spent taking care of all the stuff I bought lolz.

Pressures are dependant on clean evaporator core clean condenser condenser fans working orifice tube or Tx valve variable displacement maybe ecu controlled fixed displacement When charging use weight method with scales u did excellent pressures are almost are individual to each model pressures are changed by design or fault if correct charged The ambient temp can change pressures have all doors open when charging to load a/con have on recirculation ,, sucking in air from engine bay is not normal check pressures at idle and 1500rpm THE PRESSURE CHART IS WAY INCORRECT 115F DAY 25--35 PSI LOW ,,, 150--160PSI HIGH at idle and 1500rpm txv and fixed displacement compressor

I usually recover the refrigerant and weigh in the correct amount

Thanks Ben....great & Informative video

I'll evacuate the system and put 100 psi of nitrogen to it, then squirt a solution of water and Dawn soap on the hoses, connectors, compressor seal area and condensor with an ordinary spray bottle. You'll see the problem area quickly where you see bubbles.

If you draw down a vaccum forget about trying to reach certain pressures. Always go by weight. Get a cheap digital scale and if the system requires 34oz give it 34oz and ignore the pressures unless they are sky high

Using Dye will not harm anything. Nor will using stop leak... they are both made to be added to that system. There is no such thing as 'cheap' R134A as it's being phased out and as time goes by it will cost more and more. I do love your videos though!! Keep up the good work.

I have been watching tones of Car AC refrigerant charging video no one talked about air circulation position that amazed me because in those videos big KZfaqr included.

After covering all the basics, the best way to charge is by superheat and / or sub cool to insure you don't flood the compressor with liquid.

I work on MVAC, fan speed always on max and put recirculate on...ALWAYS. The same with a house do you open a window when you're charging a house? JS lmbo. Now as far as dye, it works well and I find it better than a sniffer just my opinion and if your look for a leak with dye if you don't want it in there flush it out, I mean once you find the leak you have to take the freon out anyways to fix it. I honestly think you did well even with a scale. I don't use scales I use a temp gauge and if it's a healthy system I can get normally 39 to 42 degrees coming out the vent. as of 2024 this will be the last year you can buy it everything goes to 1234yf. Be good bro

Very good. Thank you

You showed the connections and where the each hose/connector go, but did you opened both valves or just the low side??

Would have been nice to show & tell how you charged it. Noticed the can was upside down, if I remember that lets the liquid in. Were you adding on the high or low side and what was the method?????

Great video. The remaining freon in the high side/low side hoses is significant. How do you put that into the system once you are done OR if you hook up gauges to check the system?

if I'm not mistaken, I'm sure I've heard in a video by eric the car guy, chrisfix... someone, who stated that new refrigerants come with the dye already imbedded in the gas to help located a leak. I'm 90percent sure on that fact.

Do you ever clean under the hood? Dirt will wick plasticizer out of plastic parts, making it brittle and prone to crack, then you get leaks, then you have problems that are very hard to locate. I actually use a pressure washer to clean, and apply protectant like armourall to hoses and plastic parts. 2004 f150, 164,000 miles. Runs like a swiss watch. 😊

It's actually fairly difficult due to inside fan speed choice and outside condenser condition, fans and temperature. Don't run the inside fan at full speed but do run on recirculate. Recirculate is the only position that should be used unless the inside ambient temperature is above the outside temperature, this is what that feature is designed for. (Unless Bubba let's out a giant fart) Master Ase and IMACA certified instructor...

Please do a video on changing from R-12 to 134A, show all the steps and what all the pressure readings should be to get the 134A car vent temps as low as the R-12.

Good info sir thanks..

Thank you Ben.. Sure enough the cabin filter was clogged with leaf debris . Thank for the smack in the back of the head...I should of thought about it but didnt know that the van had one behind the glove box.. Fixed.....

Does it matter which end of the hose is on the gauge

I've got a situation on my 2016 F250, 6.2 gas. This year for the first time 137k miles, when I come to a stop the AC heats up, as soon as I get to speed it cools down. My gauge showed low on R134a, so I added some not much, and the pressure was ok. But still the same situation happened. I don't have a condenser fan, just a cooling fan. If you have an idea where to go next, I would appreciate it. Great video by the way.

My question would be....What do you do if the ranges are too high, how to bring down the pressure into the proper range,

Adding the refrigerant every 3-5 years seems the most practical solution for Ford vehicles.

The last few 30 lbs 134A 😅 I bought came with dye in it ….

In my Subaru's factory service manual it says to set recirculation to ON and open all windows. I would really like to understand why this all matters. Thanks!

Be very careful about keeping AIR out of your system. Purge your gauge lines before hooking them up. I actually installed ball valves on the ends of mine to keep them completely sealed. The Schrader valves are a highly likely source of refrigeration leaks. They should probably be changed out if there is any significant leak in your system.

What's missing in this video is how to check (step by step) the refrigerant level using those gauges.

I saw your pressure chart that shows about 340 psi at 100 degrees. I've found quite a few charts that show 100 degrees closer to 120psi and that's more inline with what is on the front of my manifold set. How do you know which chart is correct? The app from the Freon manufacture (chemours) states about 135. 135 seems low to me but who would know more than the one who actually makes the refrigerant? Edit: finally charged. 2,000rpm. 40/365 with 128 degree condenser air inlet temp. 158 degree high side line temp at pressure tap. Upon test driving, 40 degree outlet temp.

Hello Ben: So I have a question that I believe is closer to your area of expertise. I have a mini split, but it is a 24 volt system that uses a variable frequency compressor that I use in my RV. These are designed to be energy efficient, but they probably don't produce the same kind of output as a traditional one speed compressor would. I can tell when the compressor is at max speed just by the sound, and I can also confirm by the wattage being used. I'm assuming that low pressure and high pressure readings are only valid when the compressor is running at full bore--correct? For an automobile I don't think this is even a factor, the compressor is either on full output or off. Since the head unit or evaporator is indoors (Inside the RV in this case) I'm assuming I should be using the indoor temperature and not the ambient temperature outdoors. Alternatively I guess I could open the doors in the RV so everything is the same. Since this test is based on ambient temperature, this seems to be a critical factor so I wanted to ask for your suggestion. In my experience with this mini split, it only produces the extreme cold temperatures very briefly when the compressor is at full bore, and then it's cycles back down again. I think this is a trade-off for energy efficiency as this runs off a battery. Nevertheless, all the more reason to get it as cold as possible. Again I just wanted to ask about where I should be taking the ambient temperature reading, because I'm talking about a mini split, and then I'm also assuming that the pressure is only valid at full power on the compressor. I've even seen guys with automobiles rev the engine up to 2500 or so to get the readings. I think you're just using idle speed, so that part is a little confusing as well. Isn't pressure going to go up on the high side with higher revs and the low pressure lower? I don't know which one is correct, but most Mini split systems only have one speed. My situation is a bit unique here with a variable frequency Compressor, but I think the basic concept remains the same. Your comments and feedback Appreciated.

Excellent video 5 ⭐️

Thanks

My truck’s low side pressure is too high. Freon is good and no leaks but it is not cooling. The mechanic said there is restriction and that I need to change the compressor and accumulator. The compressor is working it is just not cooling. What is your opinion on that?

I need some of those auto ac guages

I just filled with a can and the aircon stopped working.I started bleeding from the low point seemed warm air was coming out,then suddenly cold gas and it started working again.Must have been air in the system.

3 Bar is to high on low pressure side. It should be 2 Bar. It is overfilled.

I always add dye. Best way to find slow leaks IMO.

Good video. Is there a rule of thumb for what the equalized pressure should be if the engine is off and cool high and low equal)?

So I’m guessing a 50-60 degree condensing temp then? And an evaporator temp of 35-55?

What do you do if the compressor is not running because of the low pressure switch?

Don't do AC but interesting, thank you

I would recover and add nitrogen to find a leak

What tips do you have to diagnose & fix an overcharge condition?

What if my pressure is at 80+ from what the AC pro gauge tells me

I would rather buy a small bottle of DYE that is perfectly fine to put into the system and find a leak then spend $340 which is the equivalent of about 34 cans of refrigerant

So the only correct way to determine anything with wrong with the system and while I'm typing this I see you talk about over charging it don't ever do this it's not the more the merrier! And there isn't capillary tunes in a car ac unless it's like 50 yrs old

why is your refrigerant tank upside down? You're supposed to be feeding gas not liquid...

Where can I find that chart ?

Hey Ben, Rookie question- I noticed some of the manifolds like yellow jacket and Mastercool don't have the sight glass on them, but they look sturdy as hell.. Is the sight glass needed for pulling a vacuum etc?? Thx

My truck's ac blows cold but barely to the point that I have to drive with my hands on the actual ac vents in order to cool myself down. The problem is that everything in my ac system is new, except the evaporator, all other parts have been replaced. My pressures show normal low side but high high side but in my case the orifice tube is new and shouldn't be clogged at all. What else can be the problem? Thanks!

Can you use 1 set of gages for different refrigerant types?

When doing a recharge with a manifold set- I'm guessing keeping the high pressure coupler value should be open? But the high pressure value on the manifold is always closed while the vehicle is on + compressor on. Is this correct?

What about if one car takes 850grams of refrigerant & another only takes 450grams ? Is that pressure chart accurate/universal for any charge of refrigerant or a particular charge ?

Hi sir. I have a three doors True cooler that uses R134A gas. If the temperature in my store is 75 degree, what should the low side pressure be? Please help. Thank you.

What RPM should I have the vehicle at? I notice a huge change in pressure at idle (~950rpm) vs 2000-2500rpm.

With the tank upside down like in the video, does it matter if you charge through the high side or the low side?

I put new lines and a condenser in the ac of my car but still not cooling down?

Fords have UV dye from the factory.

I would like to buy some cans of R134R and sent to Australia

Use a pressure chart at your own likely catastrophic risk to your entire auto HVAC system; it is not accurate. No mention here that humidity is also a factor in the chart. Any attempt to add refrigeration is fraught with risks which could exceed mfg quantity specs, resulting in super high pressure and compressor destruction. Modern vehicles auto AC is measured in volume which should not be exceeded. The entire system should be evacuated. Detect and fix Leak. Drain and refill compressor with correct amount of PAG and use PAG oil with UV dye. Losing “Freon” means you’re are also losing oil. Vacuum system per protocol. Only than measure and add charge vehicle according to specifications. ASE.

Plesae dont ever use stop leak on system thats use rotary blade compressor like patco system it will damaged the compressor shortly

I always recover what is in the system and then weigh in the correct amount... No Guessing...

If using a dye, check what the manufacture recommends. For example, there is only one brand of dye is approved by Honda and recommended by Honda for use in its vehicles. The claim is that other dyes may contain additives that might damage seals/gaskets and possible corrode other parts of the AC system. I would strongly urge not putting anything like sealers in any AC system.

your low side gauge is busted/wrong

Tool too expensive! I'll sniff with my nose. Thank you for the tutorial.

Fahrenheit is not measured in Degrees

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Shitty EU regulations you have to buy r134a from industrial ac repair guys, cylinders are not sold

None of this temperature will work that you have described on variable valve compressor which is what all recent latel model cars after 2015 has it. The knowledge you have on residential will not work in Automotive because , fan speed, variable valve compressor , change in speed of air at condensor (based on car speed) all affect pressure and heat.

In the automotive world of A/C, dye is used 99.8% of the time and in no way affects reliability.

Here is what I do that will horrify pros. When my A/C stops working, I stop at Walmart and blow a can onto my car. Than it works for a month or so. 2 or 3 cans a year is pretty cheap compared to A/C repair.

All these videos that suggest adding gas to the A/C system are false. You need to vacuum all the gas in the system, due to air contamination, then add totally new gas.

Lol so much of this is wrong you really should have not made this video but I love it when people do this shit I end up with the car at some point and I make money!

check for a clean condensing coil is easy?? OK, then show it?? Don't just talk about it.