I called AirGas and the cylinder and gas along is like $400.
If I get a cylinder off of Amazon it is cheap, but Airgas wants it to have a pressure test tag or they will not fill it…
Nothing used on craigslist.
I agree that a
nitrogen test would be best, but when you add up:
- A cylinder.
- Filling it. (See the cost of nitrogen, it is the same as R12!)
- A regulator for the bottle.
- A gauge set with the adaptors for the r12 Schrader’s…
- A Nitrogen sniffer.
It adds up to a lot more trouble and money that just doing the two step with driving to the shop.
I do have a large argon – Co2 tank with my mig welder. I wonder if I could use that to test it?
James
From: Kevin
deGraauw <kdegraauw@xxxxxxxxxxx>
Sent: Friday, August 30, 2024 07:34
To: James Douglas <jdd@xxxxxxxxxx>; Ray Jones <1970hurst@xxxxxxxxx>
Cc: John Grady <jkg@xxxxxxxxxxxxxxxxx>; Chrysler 300 List Server (chrysler-300-club-international@xxxxxxxxxxxxxxxx) <chrysler-300-club-international@xxxxxxxxxxxxxxxx>
Subject: Re: {Chrysler 300} Re: A/C Fun
If you can find a way to charge it up to about 150 psi with nitrogen and be able to let it sit overnight, you will easily know if that repair will hold.
That RV2 compressor on a really hot day with an extreme hot load on it will probably only see about 200 psi +/- on that discharge port with r12 on it. If you convert to r134a, then
it's like 20% higher pressures.
I've known old timers use dry shop air and try it but it has to be filtered and dry or you can contaminate the dryer. Best to use nitrogen as it is completely inert and won't corrode
anything internally.
The alternative is pull a vacuum. Yes a vacuum pump can be brought on Amazon or Ebay for cheap, can even be rented from a big box auto parts store, but you will need hoses and fitting
adapters. Again all online and pretty cheap too. Worth the investment for sure, especially if you know how to use it- pays for itself quickly. The vacuum " holding" test is what the shops do since it's a quicker turnaround time- if it holds at 28 in hg for
a half hour (after about 45 mins of vacuuming time to boil off moisture and air ) with pump off and gauges closed, they charge it and send it. Doesn't clog up their service bay with a car overnight.
My only different advice here is I would stick with mineral oil or a clear sealant like Nylog blue before I would use a Rectorseal, mostly because of the microscopic level of refrigerant
and how the system was engineered to seal with oil and not a sealant. If the refrigerant techs use and swear by Rectorseal, then I learned something new today- that's pretty cool.
So to avoid multiple trips, consider the investment into some proper tools and a bit of nitrogen. You WILL be recharging this system over time again since that front shaft seal
needs constant lubrication or it seeps (probably saw this on every single rv2 and york compressor I have ever laid eyes on). You can experiment a bit with some of the advice on here too that way without driving so much. Just be sure to pull a good vacuum when
done for at least 45 mins or so right before you charge it up and it should be good to go.
Good luck and keep us posted!
Since it is R12, I cannot buy it. The cost of a nitrogen bottle, gauges, sniffer and the like adds up around here to $500 - $700 or more…
So yes, it is a PITA but as of now it is still less expensive to make the drive.
James
You can test the system yourself. Might save a trip.
Gauges and Sniffers are fairly cheap these days. And a can of refrigerant is also cheap.
I'm sure there are plenty of u-tube videos showing you how to do it.
This is a test, so you do not have to evacuate. You are merely putting some ref. into the system for the Sniffer to look for.
Do your repair, hook up the gauges, dump in the can, and run the system.
Now, use the sniffer to check for leaks. None found, you can then go to have it properly charged.
Later, you can buy a Vacuum pump and charge the system yourself. Save all those trips and wait time.
I am starting to think that I may use both the square shape o-ring and the gasket with some rector seal on it. I will clean everything with lacquer thinner so the rector seal will
not sit on any mineral oil.
My problem is I have no way to test it. I do not have a nitrogen bottle nor a sniffer. So, every change I make has to go back to the shop for them to charge it and see what happens.
A PITA.
I am also going to get some new bolts for it so that I can be confident that I am getting a correct bolt stretch (torque) when I tighten it down.
Thanks Guys, James
I agree totally with the thinking in this email . Right on
I want to share something , and it may grate against “ experts “in ac but I realized long ago they are humans and form opinions at the factory and in the field that then make
it into service manuals , warnings , folklore etc etc .
Opinions are not always knowledge (!!)
I am an engineer who really tries to understand , not listen to things unless they really make sense or are technically sound in the basic science .
That little soap box is needed for what follows .
So i have installed maybe 8 mini splits , two of them , the first 2, lost refrigerant over say a year or more . They run higher than car ac , maybe 500 psi . They use copper flare
joints you have to make .I noticed some accessory aftermarket commercial “ line sets “
( sold with one end flared ) that are made here ( not Japan) had obviously been flared by an animal , —- leading into later
I had used a home depot line flare tool that drives a cone down the centerline of the tubing like a brake flare . Looking carefully ,,and more important, thinking about it ,
this moves the cone in longitudinally — it will put scratches in the copper at a microscopic level axially aligned with your flare cone ( bad news)
It turns out the really good tool , made by rigid , the cone is positioned slightly off center on an offset arm and on a bearing so it rolls around the cone expanding the copper
out at one point at a time . That IS important . Any scratches would tend to be long and spiral (?) and probably stop and start ( you cannot see this , — if you can see it , your flare is junk . )
As this connection is behind the unit hung on the wall and the lines are cut to length , redoing it is a very huge pia , 2 person job , ( will it leak again?? ) also adding refrigerant
,,gauges all that huge hassle like James describes . I ‘d rather think about it for a hour than do it three times , a day each time
So I got right tool , big $ but — used on ebay 50$ . Best 50 i ever spent ; a refrigerant sniffer is also cheap now , and a good check .
So mini split instructions say put refrigerant oil
on flare ( thinking has to be? to fill micro scratches? ) but also warnings about no sealers , will ruin the ac etc . That struck
me as BS as pressure is outward , and commercial ac flare sealers are made . I looked into them they are essentially very thick sticky oil . Better .. yes. Some are a plastic
goo , too
To my way of thinking it is still oil and if a micro scratch to outside world exists the pressure will push the oil along it . A matter of time . Gamble..
So long ago ( hard to believe 60 years literally ) I wired boilers , chillers etc for plumbers / gas fitters etc they swore by Rectorseal # 5 . it is crude ok, — ?100- 150 year
old product , very heavy oil ( horrors not refrigeration oil) with a fine particle suspension of ? extremely fine sand or powder like material stirred in . I have used it all the time on auto stuff as it does not harden . Flat out it works and one can
figure out why .
micro scratches in pioe threads ( it’s original use) but would do so also in machined surfaces like the described situation of a flange under high pressure . I do not think it
can be pushed out along a scratch due to particles .It will clog any tiny fissures because of what it is. It will not hurt todays O rings . Competing blue “ teflon “ thread seal products from
Asia are junk , or kinder , unproven
And as the push IS out at 200-500 psi it is not getting into AC ( hello? how? ) The suction line cannot exceed - 14 psi atmospheric , so no issue . And care applying it obviously
. exactly right
Good news for me is now zero loss of refrigerant since doing this , much to the chagrin of AC techs who believe tooth fairy stories in folklore and on little bottles
Thinking more , a slightly rough surface finish ( machining ) filled this way with non traveling non hardening yet flexible filler is to
my mind much better than a mirror finish you try to get scratch free and use no filler . A gasket finish spec is a similar situation
And this thinking applies to factory flare joints too .
You mileage may vary … but you won’t need refrigerant from
joint leaks , ever, if done even reasonably correctly . And you will
know why … adds confidence to your job
PS unlike Permatex ( both kinds) cleans right off , ( that stuff never worked for me , huge mess) silicone rtv can be flaky , whether it “ binds” or not to surface and thin films
of it seem weak . ( admittedly opinion!) but rtv good for low pressure gaps etc . like oil pans rear axle covers etc
Weatherstrip adhesive also very good if not coming apart , it has a surprisingly high temp rating , 3M even it calls it gasket material , but not thought of that way . It has
a place . But let it set up a few days ..
Exactly. Technically per some old FSM reference I saw when dealing with mine, you can use just the oring provided you have the exact correct one but it HAS to be the correct crush
depth when you tighten it down and it squishes onto the case of the compressor surface. It will look a little " pillowy" in the groove of the fitting side and it should stay in the groove and not fall out when you go to tighten it up. Then it will gently squish
to the correct profile of the cavity. A round oring one won't do this properly.
Would LOVE if someone can make these square orings in the green HBNR r134a friendly material as then it would be perfect. But the black Viton EPDM one works if it's fresh.
Also there cannot be one pit or abrasion anywhere on that mating surface or yes it will leak. Give it a smudge of refrigerant oil of choice on both the compressor mating surface
and the oring itself ( I dip my orings into a clean little bath of it) before bolting it all down, amazing what a difference that will make too.
That fiber one works on the suction side too but they technically carry a different part number for it and the hole needs to be enlarged just slightly if you are in a pinch and
can't find one. That fitting does not have a oring groove in it so it sits on the gasket just fine.
Thanks. The Gasket is shown as 1994-406, but down on the page there is a:
“SEAL, Compressor Discharge Fitting” 2008-388.
I am assuming this is the square cut round seal that fits in the groove. It is a little odd to use a o-ring of any profile with a “regular gasket, but I assume
that is what they did.
I wish the exploded diagram was better and showed both…
Thanks, James
Use both an oring (but use a square cut profile), not round one, and a fiber gasket. That steel fitting has a groove in it for an o ring- have to use that.
The fiber gasket seals the rest. When I took mine apart to service my compressor, it had both, so I found both at Classic Auto Air or OPGI- can't remember.
Do not waste your time with the steel stamped gasket, that is for later compressors with flat fitting faces on them.
For the second time I have taken the 300K into the A/C shop. The new clutch assembly is working fine. The new condenser is working fine.
Now when they try to get a full charge the fitting at the front of the compressor is leaking.
The fun part is that I have THREE different gaskets for that fitting.
-
Is a square (round) O-ring.
-
Is a “standard Gasket” and is an NOS MOPAR.
-
Is a steel one from an aftermarket dealer.
The one on the car is leaking. I will take it off in the AM. The shop tried a new O-ring and it did not seal….
Mt question to this august group is can anyone tell me which one they have used and it does not leak and/or does one use a combination of the O-ring and one
of the others?
Since it is a 40-minute drive and waiting around for 4 hours each time I go to the A/C shop (nobody in San Francisco can deal with old car A/C) I end up killing
an entire day. I really do not want to go for round three and come home warm.
Any ideas would help? I have a couple of spare fittings, and I took the better looking of the two and hand lapped it on my lapping plate in a figure eight
motion to make sure it is flat. The only other thing that may be possible is the furnace braze of the tube to the mounting plate may be leaking and the shop is perceiving it as the sealing material. The problem is that I do not have a compressor that can generate
250 PIS head pressure at home to test it.
Hug!
James
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