Flushing A/C components

[Frank B]

Last summer I did the 134a retrofit on my 89 gl-10, this year the compressor wouldn't even engage. So I tried to add some 134a and it took some, the compressor engaged and the air was coll at 50 degrees. Next day warm air, but the compressor engaged. I do believe some of the problem is the retrofit refrigerant I used. it had oil, stop leak, seal conditioner, and leak detector in it. the system is full of green funk oily foam. I have read about the laquer thinner but i would like to flush the drier too.

I don't want to throw a ton of money at this thing since it's going to be replaced in a month or so.

 

Any ideas??

[Hank Roberts]

A mechanic I know tells me he's started being very, very careful buying refrigerant -- every relatively inexpensive container he's had for the past few years he's had tested and found all sorts of crap in them that didn't belong. Propane, industrial waste gases, just nasty.

 

He's having the same experience with his auto parts suppliers -- anything relatively inexpensive is very unlikely to be what he paid for these days, lots of fake parts in convincing packages.

 

Apparently it's easier to copy the packages perfectly (sigh).

 

Oh, this guy repairs big Dodge firetrucks and such -- where he really has to get good parts.

[DaveT]

So I tried to add some 134a and it took some, the compressor engaged and the air was coll at 50 degrees. Next day warm air, but the compressor engaged.

 

Sounds like there is a leak. If the leak tracing dye is like the stuff I used, you look for the leak in the dark with a black light.

 

If the system was not working for a long time or open to the air while repairing, the system should be connected to a vacuume pump to remove the air and moisture before charging the system. Not a bad idea to replace the filter / dryer in that case also.

[skishop69]

Rule #1... DO NOT FLUSH the sytem with anything other than AC flush. Castrol makes it. Anything else will have adverse effects on the seals, hoses, O-rings and compressor. I'm with Dave. You've got a leak somewhere. However, it's not uncommon to get 'green funk oily foam' when you vent the system into the air (which is a big NO-NO by the way) The combination of the PAG oil and tracer dye pressurized by the 134A will do that. It's actually normal as long as by foam you don't mean cotton candy style foam. If you really want to flush, remove the compressor and drain the oil (overnite) then add the flush a little at a time using compressed air in between doses to one side of the open line and run a hose from the other line to a bucket to catch the waste. After the last batch, run compressed air through untill it comes out dry. You may want to pull the receiver/dryer and empty it as well. Refill with correct amount and type of oil and recharge. Make sure to block off or tape off your hoses while the compressor is off. It only takes a short time to ruin the dessicant in the dryer.

[no-coast-punk]

Moisture in the system can cause foaming as well. Moisture is very difficult to get out of a system after it has sat for a long time, and most shops won't take the time to do it right. Some shops don't even have a means of drawing a vacuum on a system.

 

The only foolproof way to resurect an A/C system that's been through what yours has is to use a proper A/C machine to draw a vacuum on the system and let it hold the vacuum for about an hour. This will force any h20 in the system to boil off.

 

Bring the system back to almost atmospheric (just an inch or 2 of vacuum) and let it sit. This will cause any moisture still remaining to spread through the system.

 

Apply a vacuum again and let it sit for another hour. If the system is leaking, You will know at this point before you go wasting refrigerant.

 

If the system is leaking, use your favorite leak detection method and fix the leak.

 

Replace the reciever dryer and then charge the system to capacity. Assuming your compressor is healthy the system should now give you years of trouble free service.

[idosubaru]

frank,

a very good friend and mechanic told me when retrofitting never to use R134a with oil in it. he said the most consistent results he has is just converting straight to R134a without any oils. mixing of the oils is a bad thing. but this is all talk, lets get down to business.

 

if you're not planning on having this vehicle long and the A/C is working i would't worry about flushing it. just recharge it to where it needs to be. it's probably a leak causing issues, not the stuff in the system (maybe not ideal but doubt that's keeping it from working entirely if you just put one can in).

 

recharging won't mean much if you have a leak. the most probable cause of leaking on a car of this age is the valve stem core. often you can see wetness or tiny bubbles if you peak down the ports at the base of the valve stem cores. but if you've recently charged it'll be wet anyway. replace these as they have tiny seals at their base.

 

replace the valve stem cores on both high and low pressure ports of the a/c system. if you don't want to buy the $3 tool to remove them or open the system up to replace them, you can tigthen them a bit and hope that seals any leak that may be there. there is also a tool that allows you to replace them without opening up the system, but they are much more expensive.

 

if you do open up the system then that's the time to go ahead and buy the generic box of a/c o-rings at the auto parts store and replace the o-rings at every fitting that you can easily get too. only takes a few minutes and tightens everything up.

 

i just did all this on tuesday so it's fresh in my mind. i was adding charge last summer and it wasn't holding. i replaced o-rings, valve stem cores, pulled a vacuum and charged. all is well now.

 

you could just vent the system to the atmosphere, the high pressure will blow some of the stuff out. then recharge.

[Loyale 2.7 Turbo]

...you could just vent the system to the atmosphere, the high pressure will blow some of the stuff out. then recharge.

 

Yes! it`s true... it happened to a friend`s Hatchback in the year 2001... I was with him, at the air cond. mechanic, near of the engine when a big explosion of one pipe`s fitting did occur...

Hapily, no one get hurt... but it was very close... so I suggest that grossgary said, and be carefull... also I must tell you that the direct contact with the skin of the R134a or freon R12 etc... can be VERY dangerous... so be carefull.

Good Luck!

[DaveT]

Here is something to help with A/C repair.

 

Find an old window air conditioner. The important part is that the compressor housing be a round cylinder. This indicates that it is NOT a piton compressor.

 

Make note of the wiring from on/off switch to the compressor and capacitor. Note the small copper tube that goes to a very small tube. This is the output side. Note the larger tube that comes from the outdoor heat exchanger (condenser). This is the input side. At the least, install a flare fitting & adapter on the input side to match the fitting on the car system or an A/C manifold gauge set. (find on ebay) Or as a minimum, a ball valve between the compressor and the system under repair.

 

I did this with the compressor from an old GE 5000 BTU air conditioner. It pulls a good enough vacuum to boil water at room temperature.

 

You do have to be careful about the run time, since the compressor motor is designed to be cooled by the circulating freon, which isn't there when pulling a vacuum. When it starts to get hot, close the valve and shut it down. The valve is needed - otherwise, air will leak backwards through the compressor.

[no-coast-punk]

^^^^

 

Bloody fantastic!

 

That's one of the best shade tree fixes I've heard in my life... and I've heard bunches.