Very informative. I went through the whole charge process after vacuuming and holding, only to have it leak out of the high side port when disconnecting the hose. So very helpful video. I wish I had tested my ports, now I have to recharge.

Thank you for this, so many mechanics fail to test the vacuum through the service ports and then send you on your way with leaking service ports.

Good video most people don’t know the importance of proper test and vac procedures.I watched the video all the way because I wanted to see if you where doing the same way they taught me in class and you nailed it .One might think you are an HVAC-tech!

I just vacuumed my 2004 Chevy 1500 down. Sat for about 20 minutes and I didn't see a change. I recharged and two days later it wasn't working. I suspect valves. Wasn't sure how to test. But now I know. Thanks for the video

Thanks so much; I was going to replace the whole manifold hose assembly until I saw your vid.

Very helpful video. Helped me understand the process to replace high side valve and properly evaluate the system. Thank you!

Well done Sir. Very thorough and clear on the correct way to do the work. Excellent on your side to put in the part numbers.

Thanks for all of your content over the years. I feel like we've been on the 6.5 journey together. I have a 96 k2500 suburban and have done many of the same jobs using your videos to prepare myself to do the work. I appreciate you continuing to produce this content that helps to keep these 6.5's alive. Keep on truckin man. Thanks.

@birdsong985

2 жыл бұрын

DR shock mother hos a 2000 grand prix her shifter cable is bad per the shop they been lokking for over a week for one at junk yards and looking online now. I am terrified cause she does not have money for new car if we cant find one. What do you suggest and thank you

@DrShock

2 жыл бұрын

@@birdsong985 This is kinda of an odd video to ask this on, as the question is not AC or truck related. That's a 21 year old low volume car part, you might have the shop try Pontiac NOS parts sellers.

@birdsong985

2 жыл бұрын

@@DrShock sorry I replied to wrong post. Thank you for your answer

Thank you for your video. I bought a replacement with a Schrader valve. FYI Dorman 800-955 replaces the high side port for GM and it changes it to the Schrader valve core system.

@dennydeckerful

8 күн бұрын

Did having a Schrader instead of a ball valve work?

Perfect. Thanks for the full work up on this. Just got a new to me 97 GMC 6.5LD. The low shraeder leaks like a sieve and the system emptied itself twice. I think I'll just do both and pop down to HF for the vac pump (I mean who else sells Pittsburgh stuff right? haha). I think I'll also do the Dorman swap for the high side mentioned below. Good stuff. Thanks again

Extremely informative, thanks

Thanks brother made it super easy

I learned the simplest jobs can quickly go south on you changing a high side port like that and not knowing I needed a special socket lol had to replace the line going to evaporator from condenser on a regal GS

great video, well explained. Thanks!

Well done.

Nice video

I thumbs up your video & made no# 911... That tool that suppose to change out the valve does NOT work for me either... When I first seen that about 4-5 years ago. I said I gotta have it... 😂😂 Only to find out the 💩 do not work... It's just sitting in my tool 📦 still looking brand new.... Good video though... 👍

I'm gonna try this on my s2k

I see Dorman sells a high pressure replacement that converts it from a ball to schrader valve, are they worth it?

Can you tell me where the office valve is on a ‘99 Silverado?

Vicegrips work great for that special socket

My nephew and I, had a problem, trying to get the shrader valve out, of his 2004, Acura TL? We were able to loosen it all the way, but we weren’t able to pull it out, all the way? That first tool you showed, looks like, what he might need? Can you tell me, where you can find a tool like that? I tried, tweezers, a small hook, with handle, and a small pair of needle nose pliers? I couldn’t get it out, for the life, of me? Thanks👍

@DrShock

2 жыл бұрын

Those tool links should all be in the description of this video.

Great tutorial, do you have a tutorial on replacing the low side service port?

@DrShock

9 ай бұрын

Its covered in this same video as a bonus. Check the chapter listing.

My high pressure port leaked out all refrigerant, but won't/ can't turn off to be replaced. Seems like it's fixed

Thank you. The service manual appears to reference 4.0 lbs of R134a required for a Suburban with rear a/c. What source are you using for the 3 LBS 8 oz referenced in the video?

@DrShock

2 жыл бұрын

The service manual is not the best source for these sort capacities as GM did not often update it for different options (front and rear AC options both installed), model year changes, or changes in powertrain teams. The most accurate information will be the GM factory refrigerant charge sticker under the hood, affixed to the top of the ACDelco accumulator if you have not had an aftermarket one installed. That is the source I use.

Great video! Thanks. I'm replacing the high and low side valves on a 97 BMW. I've read to use mineral oil for the o-rings, but I've seen many folks advise PAG oil. Thoughts?

@DrShock

Жыл бұрын

Can't say for BMW as I do GM, but for GM vehicles only genuine PAG oil is authorized for servicing these parts.

@DonBMW

Жыл бұрын

@@DrShockthanks! Yeah its a BMW but uses Denso parts (Japanese). I’m going to use PAG46 oil and will lubricate w the same. That’s the brand of a the o-rings and valves i’ using also.

so when you pull the freon out of the system, does the compressor oil get pulled out with it? Trying to understand if compressor oil has to go in if the system looses its freon due to leak. I did notice hissing at the High pressure valve when the cap was removed. Thinking about getting the manifold gauge and vacuum pump to try and recharge my system in my 2000 chevy 3/4 ton truck. What other tools would I need? I dont mind buying the basics to save the crazy amounts the shops are charging to do this. Background: It had low freon because the compressor was kicking on and off every second or two. SO...before doing enough research I added a partial can of the AC pro 135a recharge from Oreilys using the directions. I got it up to what I think it too high now. Right at the top of the green on their gauge and just below the yellow. The AC works slightly, but never got really cold like it should. Any advice? thx

@DrShock

2 жыл бұрын

It's rare in my experience to get any significant amount of PAG oil out when evacuating the existing refrigerant charge using a recovery machine. The vast majority of the PAG oil is going to stay in the compressor and evaporator (with most of the rest in the accumulator and condenser). You typically only lose a significant amount with a sudden large leak (e.g., a hose rupture) or when changing the compressor, evaporator, or to a lesser extent the condenser or accumulator. To know where you're vehicle is at, you really need a set of AC gauges and the service manual. That way you can determine the state of the refrigerant charge more specifically. As well as determining if the pressures indicate the other components are operating normally.

@rbljackson

2 жыл бұрын

@@DrShock thanks.....planning to get the gauge next.

I have a 94 Fleetwood Flair motorhome on an Oshkosh chassis, it uses a GM turbo 6.5 Diesel with 4L80 E transmission, previouse owner changed the ECM and the Prom. according to his notes the ECM thinks its a 6 speed and goes into safe mode and won't shift up, unless I disconnect and reconnect. can't seem to find anyone that can help, they say it's too old. can you help?

@DrShock

2 жыл бұрын

I did a video on these PCMs at one point, it might help you for the correct PROM for your chassis cab truck application - kzread.info/dash/bejne/laiam5WRdrW5hbA.html

What is the difference between a deep socket and the "special tool" to remove the high side ball valve? :)

@DrShock

3 жыл бұрын

Ha, yeah I thought the same thing when this problem popped up. But after looking into it some more when no socket fit properly, that valve is not shaped for one. Since it's made of aluminum, and usually factory torqued in there, the unique tool is required to avoid _extra drama_ ;-)

@1947froggy

3 жыл бұрын

@@DrShock Thanks for getting back, the one on my 2002 Suburban is 6 sided like most sockets, I was thinking the octo (8 sided) socket came later to prevent/make it harder for diyer's to participate in a/c maintenance. :)

@DrShock

3 жыл бұрын

The one in this video is a 1999, old body style, and all original. So it's not something that came out leter. Could it be you have an aftermarket AC line or valve, which may not need the unique GM tool to replace it?

@1947froggy

3 жыл бұрын

@@DrShock Well, I'm original owner. I vaguely recall an a/c service maybe 10 years ago, so, maybe they did that. Could be different diesel v gas? Puzzler. :) I ordered parts to do gm original or Dorman conversion and a socket in case. :)

I've got an AC problem I can't figure out. Could you please help me? I bought a 1990 Ford f350 diesel. The AC was not working. I checked and found that the system was empty. I found a leak in the evaporator. I bought an evaporator, an o-ring kit, and a receiver dryer. I changed the evaporator out and a bunch of o-rings. Then I added some oil with UV dye and pressurized the system with air using a cheap Ebay manifold set to check for leaks. I ran the truck for ten minutes. I found no more leaks. I let it sit overnight. The pressure did not go down overnight. So I thought I was good to go. I installed a new receiver dryer and then vacuumed down the system for an hour. Then I put 50 oz of R-134 into the system. Everything looked good. I started the truck and the system seemed to be working. But I got interrupted. I shut the truck off and partially closed the hood but I left the manifold set connected. I came out today and the pressure on the entire system is at zero. I even cracked open a line and no pressure. But there is no sign of refrigerant leaking out anywhere. I even waited until night and used a UV light and nothing. No sign of a leak but no pressure. I thoroughly inspected everywhere and there is no sign of refrigerant leak. I'm at a loss for what to do. It makes no sense to me. I would gladly pay you for a consultation and advice via paypal. Everyone's time is valuable. Any help is greatly appreciated.

@DrShock

2 жыл бұрын

Typically with these difficult to locate leaks, I will vacuum down the system and then add nitrogen on the high pressure side only to around 100-120 psi at the tanks regulator. Once at this pressure, shut off the nitrogen valve and listen while watching the AC manifold gauge pressure to see if it drops. Typically nitrogen testing will surface leaks that do not show up on a vacuum test (though you still need to do that test too). If you do not hear anything, then I'd next start with the soapy bubble mixture you can pick up at your local Home Depot or Lowes for propane/natural gas pipe leak checking. Applying it at every hard line weld joint and every crimp to a rubber hose in the AC system. Nitrogen is very cheap, you can pick up a small tank at your local PraxAir or Airgas center. The regulator for the tank will be the most costly purchase. But you can use this for tire inflation also, superior to just air as no moisture going into the wheels to corrode the TPMS sensors.

Mine is leaking from the low side. Would I have to empty system and vacuum before charging it up?

@DrShock

21 күн бұрын

Either side is under pressure with R134a refrigerant. So to replace the service valve, either high or low, you have to evacuate it in order to effect the repair safely, and legally. After the repair, you have to pull a vacuum to expel atmospheric moisture that intruded into the system during the repair before you can install a new refrigerant charge.

I had a small leak on my condenser and the gauges are showing 0. I am going to replace it orifice tube, accumulator and schrader valves while I am at it. Would there be any liquid refrigerant left in the system or does that leak out as well? Don't want to over charge it. Just a DIY er trying to do it myself. thanks

@DrShock

2 жыл бұрын

If you are sure you have the gauges connected properly to the ports in the AC system, and the valves opened at the gauge connector ends, reading zero would indicate you've completely lost the refrigerant charge. Given you mentioned you are DIYing it, just making sure you verify it's really at zero (familiar with your gauge/tools) before attempting to open up anything. You would need to pull a vacuum on it to be sure there are no other small leaks.

@farmtruck9885

2 жыл бұрын

@@DrShock Thanks for responding, but yes the connectors were on correct and the schrader valves were open and it was reading zero, low and high side. I have a vacuum pump and will pull a vacuum when the replacement parts are on. It's a 96 eldorado. So you are saying that there is no liquid refrigerant that could be in the system, evaporator or in the compressor? thanks

@DrShock

2 жыл бұрын

No, that's very unlikely with no pressure at all in the system. The R134a refrigerant is always going to be trying to get to its gaseous state. When you have a small leak, and it goes unaddressed for a long time, it's quite possible to vent the entire refrigerant charge into the atmosphere over that time. The more R134a vapor you lose, the more R134a liquid converts to vapor until there's no more charge left in the system. Pull a vacuum on it before removing any fittings though, just to be sure (again I'm not there so wouldn't want this to just be a whoops I didn't have the gauge valve open all the way situation). ;-) Note that when you have damage, like a hose rupture, and you lose the entire refrigerant charge quickly, then you can also lose the PAG oil charge with it. If you had a small leak, then just replace the amount of PAG oil recommended for the new condenser and accumulator you are changing. A service manual for your vehicle should give estimates on what to use there. Worst case, replace with brand new PAG oil the same amount you drain from the old parts.

@farmtruck9885

2 жыл бұрын

@@DrShock OK thank you, I will pull a vacuum first to have no whoops. I do have a GM service manual it says an ounce in each unless it has more than an ounce then put in what came out.

Quick tip to save you some long term problems. User Mineral Oil, not Pag oil when you're lubricating those O rings. Reason is PAG oil is hydroscopic and can cause corrosion in the long run. Regular mineral oil is cheap and doesn't react like PAG oil. Use PAG Oil inside your system though! I got this tip from a guy that rebuilds car a/c compressors.

@DrShock

Жыл бұрын

While it's accurate that PAG oil is hydroscopic, this is not a real concern by GM in their service procedures for this era. The -30Hg vacuum holding part of the repair procedure is included, and required, for the very purpose of _boiling_ off any H2O that may have entered the closed system. H2O will atomize, and be thus eliminated, under this level of vacuum pressure in *all* cases. The threaded surface of the valve making contact with the o-ring on the opposite side remains atmospherically exposed always, but the expectation in practice is the valve assembly is far more likely to fail and require replacement due to leakage, long before corrosion itself becomes a concern for this particular part. No harm in using mineral oil, just not required.

I use silly putty or gum on the tip of the enclosed Schrader valve removal tool to pull out and put in the valve. Makes it stick to the tool.

Will the leak in the low side port cause the compressor to turn on and off?

@DrShock

2 жыл бұрын

Compressor cycling on these trucks is normal operation. A leak will eventually vent enough refrigerant to be too low for the compressor to come on at all. You can't diagnose these kinds of problems realistically without hooking up an AC gauge set to the ports though.

@roltyd22

2 жыл бұрын

@@DrShock Oh ok..ive got a 97 cougar 4.6 and its leaking out the port it has that stupid ball valve so im going have to evacuate it regardless,the gage goes almost to red when its not engaged and drops almost out of the green range when it kicks on for about 4 seconds

Both valves are in the SAME LINE on my 2002 4wd Silverado (California). How can that be?

@DrShock

2 күн бұрын

Note that this video is only for a GMT400 body style truck, so anything else will look very different. Not the same as the GMT800 series that came out in 1999. Both truck designs were sold in 2002, but the GMT400 design was only used for the 3500HD model that year.

If we try to recharge when we take the line off the high pressure side refrigerant blows right out is this the problem? Thanks

@DrShock

2 ай бұрын

Some R134a will escape when removing the coupler, but a _very small puff_ nothing you should see only hear. It's very hard to say over a comment forum and not viewing the truck, but it could be a sticking service valve. Have you tried recharging thru the low side, and then just checking the high side for behavior afterwards?

@todds5956

2 ай бұрын

@@DrShock thank you we will try that

Hi! Where May i buy that hose assembly? For a Chevy 1997 6.5 diésel with rear a/c? Thanks!

@DrShock

Жыл бұрын

That rear AC hose assembly was unique to the 6.5L diesel SUVs and was discontinued way way back in the early 00's. It has been _unobtainium_ for many years now. There were no aftermarket suppliers as the volumes were too low. When I've ran across units that needed leak repair I've farmed the hose assembly out for rebuilding (new rubber hoses and new crimp ends to the aluminum lines).

@voldemetallica

Жыл бұрын

@@DrShock where can i find a user one? I think the previous owner fixed it but i don’t why they removed the pressure sensor that goes there

@DrShock

Жыл бұрын

You replace the valve _without_ removing the hose assembly, as I show in the video. Even an used AC hose for a 6.5L SUV will be an easter egg hunt of a lifetime to locate.

Is that a recovery machine you used? Have a part number on that setup?

@DrShock

Жыл бұрын

Yep, here's an unboxing vid on it - kzread.info/dash/bejne/gHuurLGSptLSk9o.html

@tylrpnk99

Жыл бұрын

@@DrShock thank you!!

This is the closest I've come to what I need on the internet for any video my Schrader valve also broke and when I finally got it out if stripped I've got the new part and I don't know what to do with it I thought about trying to put it in with some red anti-seize I tried to cut some threads into it a little bit I'm contemplating using Loctite power grab all purpose interior construction adhesive or maybe even trying to solder it mine is on a Town Car 07 if you reply I will be internally grateful I've got to change out the orifice tube also and haven't been able to get it off of there try not to boogered-up anymore

@DrShock

10 ай бұрын

This video is specific to a certain model year range of GM trucks so may have only tangential similarities with another brand of vehicle. I am not familiar with the Ford / Lincoln design, but I would suspect similar to GM the entire refrigerant hard line hose assembly will have to be replaced if the metal valve threads have become damaged. The high side service valve is under considerable pressure, so there's no reliable repair method for damaged threads there only replacement.

@MikeTyson2

10 ай бұрын

@@DrShock you produced a great video. Easley I think it's the best one on the internet for the topic. I appreciate your time and effort so much it was helpful. I'm not asking for anything by saying that I don't have the money for the whole line I've tried everything I could to come up with a solution and keep my husky service dog cool through the summer. It's almost over summer in Mississippi that is. I'm going to try to cut some for a Jeanette using a small helicoil it is a little low side the high side Schrader valve went in without a hitch. 🙏♥️🇺🇸

I HAVE A 2004 malibu and the plastic cap broke off inside the valve. the valve is totally round you cant grip it with a socket to remove it. is there a special tool to remove the entire low side valve? i dont have access to the shraeder inside the valve.

@DrShock

11 ай бұрын

When you say the _plastic cap_ are you referring to the screw on valve cover dust cap? If so, you can get that out with a pick or push pin. Just work the pick along the inside edge (staying at an angle to the threads of the aluminum port and away from the center area where the valve would be) and get a bite into the plastic to start to unthread the broken off piece of the plastic dust cover cap from the aluminum threads using the pick. The low side ports of GM vehicles are typically not removable, and brazed/welded onto the low side line. Be sure to wear safety googles.

@daveshostack4950

11 ай бұрын

@@DrShock yes, the screw on plastic cap. i tried using a very tiny screw driver and could not do it, i tried melting the plastic with a soldering iron. Some got melted but I was unable to pick any of it out with the tiny flat blade screw driver. What worries me most is the fragments either by melting the plastic or by drilling into it like some other guy tried can be sucked into the line and destroy the entire system. I had sunglasses on most of the time and switched to safety glasses but the left rim of the safety glasses keeps breaking off. the fell on the floor too many times. what also worries me is if I get too close to the valve with the soldering iron I could melt the valve.

@daveshostack4950

11 ай бұрын

@@DrShock any videos on removing plastic from the valve like I am trying to do?

@DrShock

11 ай бұрын

This is a rather _uncommon_ problem, so I doubt any videos on this. I'd say the soldering iron was a definite bad call, and has made the problem worse. It's also possible to damage the valve and vent the refrigerant having such a tool in that area (the valve seal is going to be a plastic material). You'll be able to use compressed air to blow any plastic debris out of the port. But having melted it you may have a larger clean up job now. I'd suggest sticking to only a pick or similar tool and commit the carefully detailed time it will take to carefully clean all of this material out of the port without triggering the valve to release.

My 99 chevy express ' the high side was leaking..I was forced to replace the valve with a ball valve...now I'm told don't ever service this valve, because it will leak..so now I will do my vac on the low side only..

A vice grip should work, instead of the special tool to remove the high pressure port

Do I need that oil tho?

@DrShock

Жыл бұрын

You don't want the new o-ring to go in dry is all that's for. But even residual PAG oil from the prior leak can be enough, if it's there.

@jordan7290

Жыл бұрын

@@DrShock awesome thank you so much man! Hoping this will fix my ac from leaking in the future

The O ring is what actually keeps the refrigerant from leaking, not the threads, so just snug is fine for that fitting. When it's charged with refrigerant, all the pressure in the system will keep it sealed. Same with your refrigerant manifold gauges. If your fittings are leaking, you need to replace the o-rings, not tighten it down more.

I wish there was number I could call you

Guidelines for recharging the system. Link to another video ok? Mostly concerned with the high side

Best practices would suggest two digital vacuum micron gauges to be used (one on the service fitting and other directly at the pump) and vacuum to be pumped down to at least 500 micron, and then a leak check to be performed observing he micron gauges that they do not rise above 1000 micron. (personally I prefer the yellow CPS vacuum gauges). Measuring a vacuum drop with a mechanical pressure gauge is an inaccurate way to determine leaks.

I feel like getting an Amazon like dorman one that just gets rid of that goofy ball valve. Then changes it to a regular valve like the low side valve.

Funny how the owner is worried about the a/c working, but doesn't seem to care about the dirty and low brake fluid? 🤔

@DrShock

3 жыл бұрын

Being cool comes first. ;-) We actually completely pressure flushed that DOT3 fluid on this truck in a previous video - kzread.info/dash/bejne/Zpp9z7ehoLqvlLg.html but there's the normal plastic master cylinder discoloration patina on these old diesels combined with the fluid level being as expected for the friction material wear (it is time for another brake job as soon as her wear indicators start squeaking).

@getgetoutout

3 жыл бұрын

Low fluid just means it's getting close to needing new pads. As the brakes wear the piston in the caliper takes up more of the volume of the fluid from the master cylinder. That level IS NOT low. It is normal.

@SonOfAdolf

2 жыл бұрын

@@getgetoutout probably a woman posted that lol

2 finger snug? more like 3 - 5 in-lbs torque.

@DrShock

11 ай бұрын

GM does not specify any such torque value in their factory service documentation. So hand tighten only is the guidance from experience for such three decade old aluminum fasteners.

Don't hand to evacuate when it all sadly leaks out

@DrShock

11 ай бұрын

Actually, evacuation removes the moisture that would have intruded into the system in such a complete refrigerant loss situation (once the refrigerant escapes, atmospheric moisture takes it's place as pressures equalize). Most of the internal AC components will be irreparably damaged by exposure to water vapor in the air in short order.

@scottlanier5133

11 ай бұрын

@@DrShock agreed. Was talking specifically about the freon. They do make a dryer injection that converts the moisture to oil

Do not lube green o rings HNBR o rings are resistant to oil if it's black lubricate it green do not.Also make sure there are no kinks ,bends or twist in your gauge set hoses.

@DrShock

11 ай бұрын

Thanks, but the OE manufacturer, General Motors, says otherwise. So we're going to go with my fellow engineers who designed the service port valve on this one and _lightly_ pre-lube them with Polyalkylene Glycol (aka PAG oil). This lubrication guidance is solely for the physical protection of the seal during valve installation. Lubrication avoids collateral leaks via friction introduced during torque of the valve assembly. In the USA, only green color coded o-rings can be used in GM air conditioning systems, where the part being sealed is exposed to PAG oil and R134a refrigerant.