linetrash75

After washing my truck today leaving the carwash lost my a/c turns out prior owner had worked on a/c at one point and lost 1 of the steel clips that hold lines to the condenser, and used zip tie in its place . Well the zip tie let go releasing all my freon into the air. So, two questions. Do I need to have the system vacummed out? I put the line back together within 1 minute of failure. And what type of freon do i use in a 98' and does it need a special type of refrigent oil? Thanks for your help.

jed

rebal

YOUR truck has R134 in it .the best way is to put a vacuume on it. But if you really need it bad you can get a recharge kit at NAPA for $40 bucks wIth R134A it will have everything and instructions too!

CSAGrey1

Just go to Wal Mart and drop $20-$35 for an R134-A conversion kit. Takes about 3 minutes of your time and is by far the cheapest route. If you can even manage to find someone who can refill R12 (Freon) it is going to cost you a small fortune. Since there isn't much left in your system I wouldn't worry about having it drawn down. If this concerns you Federated auto parts stores (and I am sure some others) sell R12-A. It is a enviro friendly, will mix with R12 and R134-a without drwing it down and also low priced.

linetrash75

I have access to a vac machine at work just have to sweet talk the mechanics. 1 of you says I have r-134 in the truck while the comes off as it has r-12 in it. How do i know for sure? As far as the kit from wally world what does it contain I have never seen it there but have never loked for it either. what is envolved in converting from r-12 to r-134 just change some seals and such? I'm not ashamed to say I'm a/c dumb. Thanks



Jed

dslpower

My 95 uses R-134a, check on the top radiator support for a sticker indicating which type of refrigerant to use and how many lbs and or oz's it takes.

jrs_dodge_diesel

Any vehicle built after 1994 has R134a, as per EPA regulations.

Repair the hose. Vacuum down the system for at least an hour to pull any moisture out, moisture and refigerant mixed together will form a corrosive acid and wreak havoc on your A/C system over time. This is also a great time to find leaks which should also be fixed before refrigerant goes in. Only after you vacuum down the system should the A/C be charged. NEVER, EVER hold the can upside down when you charge a running system. This puts liquid in the line (low side, suction line) before the compressor. The compressor can only compress gaseous refrigerant, not liquid. If liquid refrigerant goes into the compressor you will blow out the seals and will at a minimum have to replace the compressor and have to flush the lines and make sure no trash got into the system. Also NEVER charge through the high side port. The high pressure on that side can make the refigerant can explode. And never set the regrigerant can in hot water to make it charge faster, the can will pressurize to dangerous levels and can explode.

R12 and R134a are completly incompatable. They should NEVER be mixed. they operate at different pressures and you can damage your system easily if they are mixed, even in small amounts. That said R134a lubricant and R12 lubricant are likewise incompatable. R134a uses polyalkylene glycol (PAG) or ester based lubricants and R12 uses a mineral oil based lubricant. They cannot be mixed either due to the seals in the systems, they can get eaten up and cause leaks.

Jed, you may also want to consider replacing the accumulator too. This will put fresh dessicant (moisture absorbers) in the system. Replacing the accumulator is good to do if the system has been opened for some time. Many A/C shops do this too.

For reference I looked at my truck and the refrigerant sticker stated that the truck holds 1.875 lbs of refrigerant and calls for SP-20 PAG oil.

linetrash75

Jr thankyou so very much. that all sank in this thick skull,

Jed

jrs_dodge_diesel

You're welcome. Glad to have helped.

Oh, I forgot to calculate it earlier but 1.875 lbs of R134a = 30 oz of R134a.

I have a A/C service manual here on my desk so if you need any other info please let me know.

SoTexRattler

A quick visual rule-of-thumb check for the old OEM R12 and newer R134a OEM systems: Older R12 systems come with good ole' 1/4"-AN flare fittings (with Shrader insert) on the low side(3/16"-AN flares on the HS).
The R134a systems have either a 1/4"ACME threaded fitting to make it difficult to connect old style R12 hoses to an R134a system,-OR- the special R134a "Quick Disconnect" style that is on just about all the newer A/C's.

R-134a systems use one of two types of lubricant.. PAG oil or POE oil...
PolyAlkeneGLYCOL (PAG) is VERY hygroscopic, meaning it absorbs atmospheric moisture VERY readily. If it's been open for quite some time, keep the vac pump on it for quite a while to work that moisture out of the PAG oil..
It is cheap so you know why the OEM's used it instead of POE oil...

POE oil or PolyOlEster oil, is NOT hygroscopic and behaves like (and feels pretty much like) the plain mineral oil of yesteryear.. It can be used with just about any refrigerant R-12 or R134a... More expensive than PAG oil or mineral oil... Hence why OEM's DIDN'T use it...

R-134a has no chlorine in it's molecule that made R-12 such a good solvent in mineral oils. R134a and mineral oil is like Vinegar and Oil salad dressing.. They Really don't ever mix well... The PAG or POE oils DO mix well in the R-134a (HFC)family of refrigerants.. That said, I personally know a fellow (my co-worker)that simply dumped R134a into an evacuated R12 system and never had a moment's trouble with his compressor or system. (I'm not that lucky... )


JR's_Dodge_Diesel touched on one curious aspect of R-12 & R-134a mixtures..
Separately, they have VERY similar Pressure/Temperature curves, hence the choice of R134a to replace R12...
But when they are MIXED, they form what is called a HIGH PRESSURE AZEOTROPE that exhibits much higher head pressures and weird Pressure/Temperature curves than either individual refrigerant(depending on the mix ratio)... Cooling is reduced and sometimes the compressor Relief Valve will start blowing because of the head pressures... If contamination happens, the charge must be removed entirely and a vacuum pulled on the system and refilled with a pure charge of refrigerant...
The R12/134a Azeotrope mixture CANNOT be distilled back into its two individual compounds again and if reclaimed/recycled, the recycle factory winds up incinerating the corrupted mixture...

K.

linetrash75

WOW, you 2 really know your crap about A/C. thanks for all the gret info I feel a little bit smarter now. I 'm going to see if mechanics at work can put the vac on my truck for a while after work tomorrow then get a recharge kit for it, And help install Ive watched my father recharge lots of A/C but was very young and didn't ask how or way.

Jed

linetrash75

where is the orafice tube in these trucks? mechanics thought it would be good to replace this also showed me were they thought it would be. get the line off after wrestling those spring connections and cant find orafice tube or any place that it even would fitt. I'm in the high pressure line. please help quick!

JED

linetrash75

Rubb it out guys, I did some searching on here and found the orafice tube/ expansion valve is in the line from condenser to evaporator have to buy whole new line looks like I won't be replacing that. should have A/c again after work torrow. thanks for all the help. Jed

jrs_dodge_diesel

Sorry, I didn't see this until now.

Yep, you are correct. The Orifice tube is physically located in the line. It isn't replaceable. The only way to replace it, like Jed said, is to replace the line. I don't know how much it costs.

IMO, the only time you should replace it or clean it out is if you have a loss of performance of your A/C and you are sure that you still have the proper amount of refrigerant in the system.

Bigdenny

All Domestic Dodge Rams used R134, starting in 1994.Den