ok.. its an 89 Dakota LE 3.9L.. 128000 miles. I've had it 3yrs. I decided to put in a can of supposed R12 equivalent coolant.. actually some kind of coolant with PAG oil that says it will work. And it did help .. but in the sight glass I get a flow of bubbles, then clear...then more bubbles.. etc.etc.
So.. does this mean I can try to install another can OR just let things go and be glad it works at all. I'm sure that's the first new coolant installed in about 25yrs... Its a beat up truck but I'm managing 18mpG and it runs smooth as glass. gotta proof read.
thanks...

 

Get one of the cans with a gauge on it, then check out the chart on the can as to where your pressure would be for the current temp. Go from there.

 

I got a refill can of r134a that came with a connector that had a pressure gauge in it at AutoZone. You should be able to get the same sort of thing for your system.
Saw this in a quick search. You can probably find an even better deal. Apparently there are conversion kits from r12 to r134a.

 

Note 0 - Do not, Do NOT, DO NOT!!!! Add R134a to your system BEFORE it's purged and cleaned; or better yet, rebuilt.

User R12 or a suitable top off refrigerant ONLY.

Now.

Using the sight gauge, you fill JUST until the bubbles quit. Better a bit low than too much.

But.

Your hoses are over 30 years old now, and sad to say, they're NLA from Mopar and from almost everyone else.

I had to get the local hydraulic hose company rebuild some old hoses (to get the steel ends, also!) when I had my motor overhauled two years ago. (Has it been that long? Man alive!)

I bet the hoses are starting to seep; they'll get worse and worse as time goes along.

So I'd plan on this fall, pulling the hoses, getting them rebuilt, and replacing the evaporator / condensor / receiver/dryer / both hoses / thermonic expansion valve / heater core / blower motor in one fell swoop.

RwP

 

I've known guys who put R-134 in an R-12 system but even then, they pump it down. You do not mix the two as they are NOT compatible. Yes, there are conversion kits to swap it over. You really should clean the old lubricant out and put R-134 oil in it. I bought several cases of R-12 when it started getting phased out. I either recharge with it or if the system has been converted, use R-134. I'm not aware of an R-12 replacement but I don't work on a/c much. If th new stuff is working, do like RalphP said and put just enough to get the bubbles to go away. That's what the sight glass is for.

 

I have some cans of RedTek that I'm going to use to charge my Dakota with; it's a R-12 replacement. It DOES require venting out all the old R-12 though.

Do be aware, it's related to butane; might not want that in the front of your vehicle. I weighed the advantages and the liabilities, and chose Redtek.

You DO need to put on a R134a "conversion" kit to get the right fittings on.

But I also had the hoses rebuilt; if you're using the old hoses, I'd recommend against it.

RwP

 

yeah.. I know not to mix coolants. I found some that 'says' its compatible with both R12 and r134.. I'm never going to refit this truck.. so it works as long as it works.
Thanks for the info.

 

Personally, a heater is just to keep the windows clear in the winter. I have to have my a/c though. An old beat up truck is all the better to have cold a/c just to mess with peoples heads.