R134a can, DIY recharge - leak stop question

[Craig in Canada]

I'll try to make this long story as short as I can.

The question: I have a can of R134a with leak stop, but I don't want leak stop. The instructions on cans of straight R134a say to hold it upright while dispensing. The can with leak stop says to rock the can between horizontal and vertical while dispensing. I assume this is so that something which stays in liquid phase can be dispensed - the leak stop?

Can I use this can but simply keep it upright and dispense slowly to get only the R134a and leave the leak stop in the can?

More background info:

1/ I'm in Canada. It is illegal here to sell CFC or HFC refrigerants to anyone who doesn't hold an ABC123 (forget the code) refrigeration license. It is not on the shelf of any of our parts stores. (Thank you Canadian government for freaking out over things like R134a as if they were R12). It is not illegal to possess R134a. My trusted indy wants to do a $400 leak test, vacuum, recharge, optimize cycle to treat the following...

2/ My neighbour was going down to the US and offered to pick some stuff up for me (really nice guy). He isn't really a car/mechanical/handy guy so I went online to all the major parts places and printed some instructions and pictures showing what he should look for. I said "plain R134a, NO leak stop, NO additives, UV dye/leak finder OK". He came back with a can of "R134a+ with SuperCool(TM) and Advanced Leak Sealant". I can't return it or replace it with plain R134a locally and I'd like to try to fix my problem with what I have onhand.

3/ I believe the charge on my 1998 BMW is a little low. It's been on the road 12 years with no AC work ever done, and I don't use the AC all that often. I try to run it at least every couple of weeks in the off season to circulate lubricant to the seals but sometimes it doesn't happen. Over the last 2-3 years I've noticed that while working it isn't "like it used to be". It can still get as cold as it is supposed to be (2C/35F) but at high fan speeds the vent temps can increase significantly in some conditions to 55 or even 60F. On the highway, running outside air with a high wet bulb temp in the 100sF it can still keep vent temps in the 30sF at 50-60% fan speed.

I'm sure it's nothing special now, but 15 years ago when this car came out (E39) it was unique to have a variable displacement AC compressor. It does not cycle on and off but instead varies its displacement to meet demand. This combined with fully automatic climate control make reading temperatures and pressures a little tricky. I have noted the system cycle off very briefly 2-3 times in max load conditions and I assume it's the low suction pressure switch.

There don't seem to be any blockages, contamination, nasty compressor noise or any other issues. I can't even tell anything is wrong if I start out from our garage or other shelter. It's only when the car has been parked outside in the sun and you're trying to cool it. The system calls for high fan speed but the system can't maintain a frosty evaporator temp at that speed and then it doesn't extract the humidity and the vent air isn't cold enough to really fight the heat soak and sun load. Forcing the fan speed down lowers the vent temp but then there isn't quite enough air etc... My dad has a newer E39 and in these "heat soaked car" conditions I notice his AC outperforming mine without thermometers. In less beastly hot conditions I can't tell any difference.

I have not observed any oily dirt around any of the fittings, tubes or compressor. I don't believe (but can't guarantee) that I have lost any system oil. I don't believe I've developed any kind of new, large leak. I think I'm just a "little low" after 12 years of seep past seals that perhaps weren't kept wet enough over the lifetime of the car.

I don't want to pay $400 for a full maintenance of a system that is almost fine and it burns my butt that my government has decided that I can't DIY this.

 

[StevieC]

No it's mixed in whether you like it or not. If you do not have leaks you can still use it. IMO it's a mild additive that won't do any harm.

Steve

 

[demarpaint]

I'd wait till you could get some R-134 w/o the stop leak.

I'm glad I have the license. I was able to buy Freon a few years ago for two older vehicles I own, it beats the conversion over to 134 and is way colder in my applications!

 

[Craig in Canada]

Originally Posted By: StevieC
No it's mixed in whether you like it or not. If you do not have leaks you can still use it. IMO it's a mild additive that won't do any harm.

Steve


Ah, I forgot to mention in my post. I googled around a bit and found statements where AC part manufacturers void warranties if leak stop was ever used in the system and reports that some AC shops will no longer service your system (because it voids the warranty on THEIR recovery gear) if you've used leak stop.

I'd be happy to find information to the contrary, of course, indicating that the stuff in these cans isn't whatever all of these other people are deathly afraid of.

This is what I have: http://www.idqusa.com/proddetail.php?prod=AF-1&cat=9

I should also have noted that I'm not shooting for fully optimized and I realize that overcharging is bad. All I intended to do was get the system running at max fan speed on a high wet bulb temperature day and dispense small amounts into the system until I've got a vent temp into the 40s and probably stop there.

I do have a set of manifold gauges but they were my dad's until just recently and I only have R-12 and R-22 fittings I think. Plus the fact that R134a is unobtanium here.

I wish the dryer on this system simply had a sightglass - pull the trigger until there's no more bubbles...good enough.

 

[StevieC]

That is because they can't "control" the additives manufacturers of this stop-leak might put into their oils. Of all the stop-leak incorporated refrigerant products I have used, none have caused and problems

Steve

 

[rshaw125]

Do the nannys in Canada allow you to use Enviro-safe?? I have had in my 1995 Van for 5 summers now. Not only do you not have to use very much the AC is colder than when new.

 

[StevieC]

It was on shelves here a while back but I haven't seen it lately. To be honest I just buy whatever is 134 compatible when not using 134 specific.

 

[duaneb9729]

As a HVAC contractor, working on home and business furnaces and a/c, we do use leak stop in troublesome R410a units, and it is added though our gauge sets, so far no trouble has come from that.

now we dont do it often, but in five years we have had no gauge or recovery equipment trouble. This just our experience.

Personally I would use what you have and add the leak stop, there is so little of it in there, I really dont believe that it will harm anything.

 

[Craig in Canada]

Originally Posted By: rshaw125
Do the nannys in Canada allow you to use Enviro-safe?? I have had in my 1995 Van for 5 summers now. Not only do you not have to use very much the AC is colder than when new.


We can use R134a, we just can't buy it without a license.

What is on the shelf is things like "Redtek 12a". It is said to be a replacement for R12 or R134a but is compatible with neither. You must evacuate the system and recharge with their refrigerant and oil.

I believe that my research has indicated that these products are pine-scented propane. Propane, not being a CFC or HFC, is not regulated by the same law.

Since my system is working 80% or so, I don't need to go down this path, IMO. If I had a bad problem and did a full DIY repair, I might try recharging with this stuff.

I had a previous car which was made one year before the conversion to R134a so it had R12 in it. Before I knew it was propane, my indy shop did an evac, leak test, repair, vac, charge cycle with one of those agents. It was really frosty, but I never really liked that it was just propane. That system was barely functional and needed far more action than my current system.

 

[paulo57509]

I would never put stop leak into an A/C system. I wouldn't put in any kind of UV dye in there either.

http://www.autoacforum.com/messageview.cfm?catid=20&threadid=21123

 

[duaneb9729]

Its an interesting picture on that link, Paulo, but what does the descant look like after a normal service life?

I haven't ever looked myself.

 

[sciphi]

I'd just use it and not worry. If it blows colder, great!

FWIW, I used a similar product on my 1999 Buick LeSabre's AC system that was cool, but not cold. Half a can got the system ice-cold, so I stopped there.

 

[Vizzy]

Although you might not have a problem and the car is older I would definitely make sure you use the NON stop leak version of R134a!!!!!!!!!!

I would take the car to a profesional that works on BMW.....using that additive might cause a reaction with the regrigerant oil in your car...many German and European cars use slightly different oils than most Asian and US makes!!!!!!

Sure it might cost you a few more dollars BUT you'll have a perfectly working AC system..

ON the other hand do you want to chance permanent damage to your system just to save a few bucks....

This is clearly a job that should be left to the pros.

 

[mechtech2]

"Clearly a job that should be left to the pros"?
This is not so clear to me.


If you left your can stationary for a while, had it upright when filling, and only added 1/2, you would minimize the stop leak that entered your system. But some would surely be in there.
It is not a horrible curse to have stop leak in your AC system. More than likely, you will never know it is in there.

 

[Vizzy]

mechtech...

do you work on European cars of any kind....?

Many times systems are different...quite different from what you find on the common Asian and US makes....and what works on most of these models might not only not work...but might actually cause serious damage to boot!

Unless you are experienced, especially with any AC system, you should leave it to the pros.

I can't tell you how many times the shade tree ends up costing himself a wad of cash in the process of trying to save a few bucks....

Sure the DIYer can handle basic maintenance like batteries, cap and rotor, spark plugs..ect but AC systems in modern cars must be serviced very carefully or you will cause serious damage that will end up costing a lot more than the money you spend going to a pro...

 

[brianl703]

The most notable difference in the AC system in my Saab 93 is that the refrigerant capacity is only given in grams.

Otherwise, it uses a Sanden compressor. The oil it uses is the same as other cars that use a Sanden compressor.

 

[Kestas]

Vizzy, mechtech could put a lot of "pros" to shame. Even I can often do a better a/c repair than many techs. It all depends on the persons ability.

 

[mechtech2]

Sure -all kinds. And I worked for Mercedes a while back.
And you are right - amateurs can mess up simple stuff in a mind boggling way!

But I think normal AC topping off is easy, and should be attempted by the average civilian. Homework is needed first. A dead cold static pressure read [@ whatever temperature], and a running [maybe cycling] pressure of the low side is normally all we need to simply fill a slightly low system.
I am not a fan of anti leak stuff in radiators or AC systems. But I know they are used often with no problems. And they can actually work as adertized!

 

[Craig in Canada]

So I've seen contributions from the "don't touch it" camp right through to the "it's all fine" camp

I'm hopefully to see figures that these canned all-in-ones don't have much leak sealer in them. Perhaps between that and holding the can upright I wouldn't charge much sealer at all. It's an 18oz can and I bet I need 2oz tops.

I am, however, interested in the point of view that "leak sealer doesn't know the difference between a leak and an orifice".

Discuss.

 

[onion]

+1 on everything Mechtech said. In your situation, I would keep the can upright and add half a can as a vapor charge... which will keep any stopleak entering the system to a minimum. Then see how it cools. Be sure and purge those hoses.

Yes, a DIY guy can really screw things up. But if you have your head screwed on straight and you're careful, it should work fine.

As for the stopleak- my understanding is that it's designed to swell rubber seals. I don't see how it could affect an orifice... we aren't talking about CHUNKS or anything. I doubt it'll be perfect, but charging as a vapor should effectively distill quite a bit of the stopleak and dye out.