Working on A/C, 93 K2500HD, have questions

[GM Guy]

hey all,

I am working on the a/c system on my 93 K2500HD, and was needing some advice.

has anyone successfully gotten a A/c condenser cleaned out? the fins are so much tighter than a radiator, I am debating about giving up and buying a new condenser. half of them are folded over, and the other half are full of junk.

Also, the compressor didnt fully lock up, but something came aprt, as you can only turn it half a turn, then it hits something. did much for metal filings get in the system? do I need to change anything other than the orfice tube and receiver dryer?

What is recommended to flush a system?

Finally, do they make block off plugs to keep the system sealed, and remove the condenser? What style fittings are these? I am debating about plugging off the system to keep it sealed, and pull the condenser and put off the whole project till next spring.

 

[Burning oil]

Condensers are not to expensive. With the potential metal in yours I'd get a new one. Get one for a Burb with dual air. You'll have to leave the system closed til your ready.
I'd also get a "pancake" filter for your liquid line (condenser to evap).

OR! you could put a much larger custom condenser like Im in the process of doing http://www.thetruckstop.us/forum/showthread.php?43197-Slight-redesign-of-A-C-system

 

[GM Guy]

can filings still get past the orfice tube?

would it hurt anything to put it all together and not charge it?

 

[Will L.]

Yup, leave it in there until you change it, then change it for a new one. You should be able to buy a flush kit from a local parts house- and yes flush it. Bigger condenser is enticing...

 

[WarWagon]

can filings still get past the orfice tube?

would it hurt anything to put it all together and not charge it?

Keep some pressure in the system. Waste a can... Otherwise temperature changes will try and suck moisture into the system. The accumulator with the water adsorbing stuff gets ruined and then you have ice plugging the orface tube next summer. Let alone corrosion...

The Orface tube is a screen, not a filter. Lots of grit goes through them. Flush everything including the hoses. AC flush with the compressed air powered flush gun is the way to go. Pull a hard vacuum for an hour after you are done. You have a 1993 R-12 big tube (flushable) or a throw away R134a thin tube parallel flow condenser?

 

[THEFERMANATOR]

ANYTIME the compressor fails, the condesnser should be replaced if it is the old style capilary type(sounds like yours is). They cannot be flushed out due to how small the passages in them are. Also since you say it's a 93, your probably converting it to R-134A, which means the bigger condesner will GREATLY help out the A/C performance. After compressor failure the condenser, accumulator, and orifice tube should be replaced as well as doing a thorough system flush. Also adding in a filter in the vapor line before the compressor is a good idea.

 

[SnowDrift]

http://www.thetruckstop.us/forum/showthread.php?40238-A-C-working-for-short-periods-of-time/page3

Read through this, too.

 

[GM Guy]

Truck is factory R12, and will remain R12. (allthough I will be running an R12 substitute, may switch to actual R12 if system stays sealed nicely) I ordered in a R12 specific condenser through GM. Damn thing cost more than the R12/ R134a dual compatability one.

How about this scenario:
replace condenser and nothing else to get airflow back in the cooling stack for California load that needs to happen pretty quickly, and system stays sealed from dirt and moisture. Either after trip, or next spring, tear it all apart again, flush, change compressor, receiver dryer, etc. and charge it.

Will that work fine?


Also, working a/c is good enough. Humidity is almost non-existent, and I am usually driving with windows down and fan blowing. no fancy compressor or condenser changes will be done. To make you southern/easterners (places with humidy ) jealous, on a hot summer day in Idaho, the heat index is lower than the actual air temperature. Humidity can get in the single digits. :O


Finally, what oil needs ran in the system? does it matter if I use an R12 substitute rather than actual R12?


Thanks for all the great input guys!

 

[THEFERMANATOR]

Truck is factory R12, and will remain R12. (allthough I will be running an R12 substitute, may switch to actual R12 if system stays sealed nicely) I ordered in a R12 specific condenser through GM. Damn thing cost more than the R12/ R134a dual compatability one.

How about this scenario:
replace condenser and nothing else to get airflow back in the cooling stack for California load that needs to happen pretty quickly, and system stays sealed from dirt and moisture. Either after trip, or next spring, tear it all apart again, flush, change compressor, receiver dryer, etc. and charge it.

Will that work fine?


Also, working a/c is good enough. Humidity is almost non-existent, and I am usually driving with windows down and fan blowing. no fancy compressor or condenser changes will be done. To make you southern/easterners (places with humidy ) jealous, on a hot summer day in Idaho, the heat index is lower than the actual air temperature. Humidity can get in the single digits. :O


Finally, what oil needs ran in the system? does it matter if I use an R12 substitute rather than actual R12?


Thanks for all the great input guys!

As for the oil, yes it matters which substitute you run in it. Some say they will work with mineral oil, while others spec out you must run 2 onces of ester to mix with the mineral for it to carry the mineral in suspension. If your going with a R-12 substutute, I'm guessing your looking at freeze 12 which is nothing more than an R-134A hybrid. Theres also the "other" alternatives out there, but I have yet to hear of many long term tests regarding the flammable ones out there that supposedly work with mineral oil. In all honesty I would have just swapped to an R-134A condenser from a 94 BURB, and charged it back with 134.

 

[GM Guy]

HC12a is what we buy, and yes, I think it has some propane in it, as it is flammable. I will check the label.

Otherwise, does my plan sound OK?

 

[Will L.]

I have friends that run the propane mixed refrigerants, it works well. The concern is you get in a crash and puncture the condenser blowing out 1 1/2 lbs of propane at 200 psi. "Flame on!" says the human torch. No crash and you are careful when you open the system no problem. It's ok to roll the dice, as long as you know the risk.

I would just let it all be until it's time to do it. If you want to start buying the parts ahead of time cool, just keep them sealed and clean until use. I get what your saying about humidity, The most we get is from school football fields evaporating. It REALLY hinders a/c performance. New dryer when you open it up will be worth it if your going to do it at all. I have learned, I haven't bothered fixing a/c in my hummer for last 4-5 years, but when I put it together before next summer, believe me it will work very well.

If you put in the bigger condenser, new receiver dryer & flush and go with the 134a kit, it will be with in 4-5 degrees of the r12 when it was new. I have retro fitted entire fleets and seen the results time and again.

 

[GM Guy]

condenser has allready been ordered though, so I will be sticking with stock condenser and R12 system. A/c performance is no big deal around here. if it works, that is all that matters. :agreed:

I know its best to do it all at once, but I am:
1) in a rush to get a load to california,
2) needing to get airflow back into the stack to keep engine cool,
3) keep the a/c system sealed against contamination

I would like to change the condenser to get airflow back into the stack, and not touch a single thing till I tear it apart to actually fix it at a later date.

Will it hurt anything to install just the condenser, and nothing else, and leave it alone?

Thanks!

 

[WarWagon]

Leave the plugs in the new condenser. Take a peace of hose to bypass the condenser hookups and keep them clean. Use hose clamps. I would also put about 1/2 lbs in the system to keep it pressurized. Zip tie the compressor low pressure switch wire out of the way and disconnected. (Water will get in and sit in the compressor coil wire plug if you pull that one.)

Of course you need to be biased in SC, not Kansas to use 12A. :sleeping:
http://en.wikipedia.org/wiki/HC-12a
http://www.epa.gov/ozone/snap/refrigerants/hc12alng.html

 

[THEFERMANATOR]

The 12A sounds like a good alternative to me, I almost converted some vehicles over to it years back until I found out it was illegal in Florida and thus hard to come by. They've done numerous tests on it, and found that the small amount in an A/C system isn't enough to go boom, but just a flash even if it was a perfect combination to make it ignite all at once.

 

[Diesel Nut]

condenser has allready been ordered though, so I will be sticking with stock condenser and R12 system. A/c performance is no big deal around here. if it works, that is all that matters. :agreed:

I know its best to do it all at once, but I am:
1) in a rush to get a load to california,
2) needing to get airflow back into the stack to keep engine cool,
3) keep the a/c system sealed against contamination

I would like to change the condenser to get airflow back into the stack, and not touch a single thing till I tear it apart to actually fix it at a later date.

Will it hurt anything to install just the condenser, and nothing else, and leave it alone?

Thanks!

I would recommend cleaning the condenser and getting the tool to straighten the fins out. One you put te new condenser in it could become contaminated. You could put the plastic plugs in the line and secure them. Then pull a vacuum mad long as it seals the system will be sealed from the atmosphere.

 

[WarWagon]

Don't leave a vacuum in the system. Instead of leaking freon out it will leak air/water/dirt in.

I wonder how much better the Propane refrigerants do with the weak system and unreliable compressor design we got? Esp when it gets over 110 out?

IMO no worse that trying to light a BBQ grill and it blows you across the campsite... Vs gasoline that puddles and burns. Or a runaway RV trailer that has the propane tanks on the front...

 

[Will L.]

My friends that I was referring to didn't use a propane containing refrigerant. They used propane, as in straight from the bbq. They are trying to talk me into it for the wife's mb 300d that still runs r12. The 12a is a better choice.

If your concerned about it - send a bottle to myth busters tv show so you do not try at home expelling the contents into the air under an ignition source to observe the hazards to your own assessment. yeah- that's it.

What about WW's idea of just take out your old one, and hose off the ports with something like heater hose and hose clamps to keep the system clean for the driving until everything can go in. As far as pressurizing to keep it not sucking anything in, just 10 psi would be plenty for that.

 

[GM Guy]

we have successfully used straight propane in our combine harvesters, since they are out of the late 70s through late 80s, and are R12. someone mentioned the flammability, but what is worse, a "poof" of propane igniting (small fireball) or 7 gallons of hot dexron ATF that runs the hydraulic system, and 4.5 gallons of 15w40, and 88 gallons of diesel fuel.

So you guys think it would be best to hold off on putting the condenser in, and trying to seal the lines?

anyone know off hand what kind of fittings these run? can a guy buy some caps at a hydraulic fitting store to seal it?

does the nut slide on the tube, allowing a guy to slide it back out of the way and hose clamping some hose on the flared fitting?

Thanks for all the input guys!

 

[Will L.]

You could just cut up the old condenser since you are buying a new one. Just keep a 3" or 4" long piece off each fitting, smash the end flat, and solder it up. That will keep the system from getting any worse contaminated, and you then don't have the rest of it in your way restricting the airflow to the radiator.

 

[GM Guy]

might try and save the condenser. will inspect for metal, and see if we can do much for straightening at a later date. would like to use another solution.

anyone got a junk R12 condenser they would do that to for a fee?