Diy A/c Recharging, Using the R134a / PAG oil kits

[shogun]

http://www.bimmerboard.com/forums/posts/207521

Any comments welcome.

Comments from ShadeTreePete: -quote-
Here is what little I know. Hvacdude has way more knowledge and perhaps will chime in.
1. Lots of used dealers change the fittings, and fill a 12 with 134. Works for the tail-lite warranty for a while.
2. 134 will find a way out if not sealed I think. New seals are mandatory to keep alive. Good 12 seals good for a few whiles. Took only a few hot days for 134 to find the weak seal on pressure switch.
[seal 16yrs and 194k, I admit], but 134 found it.
Just .04 (inflation - and 134 not cheap either).

had it done to my GMC recently. Here is what I learned that may be of use.
1. 134 is smaller molecule than 12, so that is reason for new seals etc.

2. If 12 systems has been charged with oil too often, new dryer may be needed [us kits come with new dryer usually]. Mine would not come loose and they really tried so stuck with old.

3. Old needs to be vaccuum out and far as possible.

4. Be sure u get all seals. One was missing on mine, the one on the overpressure switch and 134 lasted about 3 days. Replaced and still solid after 60 days.

5. I have found that the 134 does not cool as fast as 12 nor as cold. It does work fine after initial cooldown and on highway. You might find that cooler setting needed to achieve what 12 required. 12 is hard go get and expensive. 134 still going up in price but still cheaper.
So be sure you get all seals, evacuate completely and make sure all is tight before your load the 134.
Just what I learned recently. Best of luck.

-unquote-
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Summer is coming, so be prepared :)

[632 Regal]

all is true but I think the hoses on our cars are shielded and can be used for r134. havent hear anything about the seals leaking with the conversion as of yet but it IS common on american cars with unshielded hoses.

[joshua43214]

Looks like a disaster waiting to happen. I never saw anything about pulling a vacuum on the system before charging, but maybe I missed it.

Pre r134a hoses will not seal r134a well, so they should be replaced on a conversion. replacing the dryer is needed on any conversion. Adding sealer to a BMW is evil.

This sort of crap belongs on a honda forum.

[Alexlind123]

Looks like a disaster waiting to happen. I never saw anything about pulling a vacuum on the system before charging, but maybe I missed it.

Pre r134a hoses will not seal r134a well, so they should be replaced on a conversion. replacing the dryer is needed on any conversion. Adding sealer to a BMW is evil.

This sort of crap belongs on a honda forum.

Why does this belong on a honda forum? Arent we all about DIY repairs?

[joshua43214]

Why does this belong on a honda forum? Arent we all about DIY repairs?

Yes we are, but many jobs require special tools that DIYers do not own. You do not see many people overhauling automatic transmissions, differentials, or engines. They all require special tools and knowledge. AC is no different.

You simply cannot service AC with out a vacuum pump. If you convert a system, as much of the old oil must be removed as possible, the correct oil and quantity must then be added. the system must be placed under a vacuum before filling.

If all you are doing is toping up an AC system, then this product is the wrong one, You do not add oil when you top up AC, and then you have to add the proper oil, not all PAG oils are the same.

I could go on and on. Some parts of the AC system can be serviced by the DIYer, and I encourage that.

[angrypancake]

can r-12 still be obtained and subsequently used to recharge? i havent gotten around to doing the r-134 conversion yet.....

[632 Regal]

I used 409A in my truck too cold, have to shut it off every 10 minutes to thaw the evaporater...
can r-12 still be obtained and subsequently used to recharge? i havent gotten around to doing the r-134 conversion yet.....

[KenB]

Is a re-charge DIY kit available at Autozone or Peboys?

My system is a little low so that the aux fan does not come on right away when I turn the AC on, will come on after pressure builds. (was told here it is pressure activated by AC) It also comes low speed on via thermal switch (I think) if coolant temp goes over 1/2. Car does not overheat, or get to the point where aux fan goes into high speed, fan clutch is good, no radiator coolant leaks. Checked the site glass and there are bubbles, blows cold after a few minutes and will freeze you out at steady highway driving speed. Stopped at a local AC shop, they want "approx" $150 to do a system check, add dye to look for leaks $40/lb for refrigerant, etc. I think all is well and just needs to be topped off. It has not been serviced in the over 3 years I've owned it. I have done it before on my old Chevelle years ago, would like to try it again before spending a bunch of money if not needed.

Going to try to find a re-charge kit without oil or dye additive, will post results.

[shogun]

Have a look here
http://search.ebay.com/search/search.dll?cgiurl=http%3A%2F%2Fcgi.ebay.com%2Fws%2 F&fkr=1&from=R8&satitle=r134a+recharge+kit&category0=

[genphreak]

I reckon the pro shops would be a better option bud.

It has not been serviced in the over 3 years I've owned it.
how long before that did the PO service it...?

I have done it before on my old Chevelle years ago, would like to try it again before spending a bunch of money if not needed.
Which is worth so little if something needs fixing. On the e34 the risk factor is not small... atm there is nothing wrong w your system other than it has gradually lost pressure and will need a new dryer/filter. Why risk screwing it up with one of these kits?

Going to try to find a re-charge kit without oil or dye additive, will post results.
I wouldn't bother on this car, the system is worth too much. All you need is a regas and a new dryer ($25) from the local shop, no dye, no oil just regas and time changing the dryer (don't do this yourself, though you can prep the engine bay by removing the washer bottle and air-filter trumpet). It is not that expensive, You should chk your hi speed fan is working be4 taking it in of course. :) nick

[Bellicose Right Winger]

A year ago or so, my local Walmart had all their R134A cans marked $3. I cleaned out the shelf. Turned out the sale had ended, but I persisted and they honored the marked price. They have a recharge hose also.

The main reason to evacuate an AC system is to remove non-condensable air. Non-condensables collect in the top of condenser, prevent efficient condensing and raise high side pressures.

I know this will make Bill R. spill his cookies, but I've been using an old refrigeration compressor to evacuate auto AC systems for 25 years now with out any problems or regrets. I pulled it out of an old refrigerator. This was standard text book practice at the time. It doesn't pull down to the 500 microns that's currently recommended, but in the old days the procedure was to break the vacuum with a few ounces of refrigerant and re-evacuate 2 or 3 times. The refrigerant dilutes any remaining non-condensables, so that a good portion of them can be removed on the next evacuation. The dryer dessicant is more then capable of removing any moisture that might remain.

In light of the cost of AC repairs, I would encourage all DIYers to take a good look at acquiring a vacuum pump, manifold gage set and reading up on AC repair procedures. It's common sense, not rocket science.

The process shown http://www.bmwe34.net/e34main/upgrade/AC_upgrade.htm uses the "good" vacuum pump and is an outstanding guide for the DIYer. Unfortunately it has a flaw that defeats purpose of evacuating to 500 microns. It shows vacuum pump being disconnected followed by the refrigerant being connected. You've made a good evacuation and now you're going to allow hose full of air back into the system. If possible, evacuation should be done with the refrigerant can connected but not pierced. Better manifold sets allow a 4th hose to be used, low side, high side, vacuum pump, and refrigerant container.

Paul Shovestul


.....Is a re-charge DIY kit available at Autozone or Peboys?

[KenB]

Thanks for the replies, as always great input.

Today it's only 70f instead of 95 like it was last week. The fan comes on but doesn't stay on while idling but not as soon as the AC is turned on, takes a few seconds before the aux fan kicks on. It does stay on if the rpms are up over 1k. I assume because the pressure in the system is higher at a higher rpm and triggers the aux fan to come on.

Watching the sight glass; when the compressor kicks on it looks white and foamy for a couple of seconds; then when the compressor cycles off I don't see many bubbles at all.

Seems that all the available stuff has lubricant in it. Some have leak stop and/or dye. I don't want to ruin the system by putting too much crap in it.

Does the system have to be evacuated to replace the dryer?

I guess I need to bite the bullet and pay someone who knows what they're doing. I haven't had it serviced in 3 years and who knows how long it was or if the PO ever had it done. I will get it in ASAP and have it checked out.

[Bellicose Right Winger]

I've got a 9/92 525i also. Condenser fan should run low speed any time AC is on. I don't recall if fan stops when compressor cycles off. When my low speed resistor burned out fan would only run on high speed, but this doesn't sound like your problem. No bubbles when compressor cycles off is normal. I'm surprised you can't find R134A w/o oil, keep looking. System need to be evacuated any time it is open to atmosphere, it doesn't need to be evacuated to recharge. Why do you want to change the dryer? It's apparently quite a slow leak if it hasn't all leaked out in the 3 years you've had it. If it was mine I'd put a can or two in and see how long it lasts.

Paul Shovestul




Thanks for the replies, as always great input.

Today it's only 70f instead of 95 like it was last week. The fan comes on but doesn't stay on while idling but not as soon as the AC is turned on, takes a few seconds before the aux fan kicks on. It does stay on if the rpms are up over 1k. I assume because the pressure in the system is higher at a higher rpm and triggers the aux fan to come on.

Watching the sight glass; when the compressor kicks on it looks white and foamy for a couple of seconds; then when the compressor cycles off I don't see many bubbles at all.

Seems that all the available stuff has lubricant in it. Some have leak stop and/or dye. I don't want to ruin the system by putting too much crap in it.

Does the system have to be evacuated to replace the dryer?

I guess I need to bite the bullet and pay someone who knows what they're doing. I haven't had it serviced in 3 years and who knows how long it was or if the PO ever had it done. I will get it in ASAP and have it checked out.

[Derek A.]

1. Poor mans evac tool - hook a vacuum line up to the low side and let the car suck out all the old stuff. Don't hang around exhausr while this is in progress.
2. R12 charge hose works with r134 cans, just have to line it up right. I dumped two cans of the sealer/cleaner r134 in my car and thew air works great.

[KenB]

Why do you want to change the dryer? It's apparently quite a slow leak if it hasn't all leaked out in the 3 years you've had it. If it was mine I'd put a can or two in and see how long it lasts.

Paul Shovestul

I was asking about the dryer because of the info in Nick's post and Bruno's site. I am only adding not converting so I don't need a dryer?

If that is the case I will try to add a can or 2 to the system myself if I can find stuff without any aditives.

Thanks.

[KenB]

As a follow-up:

My problem was the resistor. The fan would switch on at high but not low. Works fine now. It was also a bit low on refrigerant, added 1lb.

I gave in and took it in to my indy. I asked him to check for the resistor as the fan was operating OK on high speed only and to check refrigerant.

$180 for the part, labor and refrigerant. Still cheaper than replacing the aux fan, losing the AC or overheating and blowing a head gasket or worse...all in all not bad for being the first time I've had it serviced in 3 years, I'm not complaining.

Just in time too since the temp and humidity is thru the roof today.

Blowing ice cold, full force (new microfilter in March when I had the Bilsteins put on) and running the temp guage at straight up 12 O'clock just like always. I'm a happy camper:D ...now to get my CD changer fixed...

Thanks again to all for your input.