R134a

[XZypher]

I a week or so I am planning to fully recharge my A/C anyone happen to know the correct amount the system should have for R134A.

[Bitsyncmaster]

Two or two and a half cans.

If you have not flushed the system of mineral oil, don't put in R134a.

[content22207]

Mineral oil and 134 are perfectly compatible -- it's mineral oil and PAG that are incompatible.

Use Ester oil instead of PAG.

Bill Robertson
#5939

[nullset]

Take it to a shop and have it properly evacuated. Don't just vent it to the atmosphere (illegal) and then recharge it without pulling a vacuum on it.

Why are you converting? If it's losing cooling ability, you have a leak. Take care of the leak first, then recharge with R-12 and you'll be happy.

--buddy

[Bitsyncmaster]

Mineral oil and 134 are perfectly compatible -- it's mineral oil and PAG that are incompatible.

Use Ester oil instead of PAG.

Bill Robertson
#5939

http://www.aircondition.com/tech/questions/39/Differences-between-R12-and-R134a

[outatym2001]

I sincerely hope you evacuate the air out properly before adding the R134a. Then take Low Pressure and High Pressure readings while the A/C Compressor engages and disengages.

I went to O’Reilly Auto Parts long ago and bought a can of Interdynamics Arctic Freeze Ultra Synthetic R134a. Then recently I went back a bought another can since I was going to have DMC Northwest evacuate and charge my A/C for me. Well, guess what?
I showed them the cans I bought and one reads 10 oz and the other 12 oz. They ripped me off. Those bastards. The cans are exactly the same size but the wording on the back is a little different. I didn’t recall which can was new and which was old since they are the same color and size.

The DeLorean Workshop Manual on page N:07:01 states Total R-12 charge 2.5 lbs.
For R134a Bitsyncmaster is pretty much right on since you need around 2 lbs. or 32 oz of the stuff.

[XZypher]

My car is already converted, I am just doing some A/C work this weekend and the system is empty currently.

[XZypher]

I have access to a vacuum and all that good stuff, so it will be done before its filled thanks for the concern tho.

[content22207]

http://www.aircondition.com/tech/questions/39/Differences-between-R12-and-R134a

"They seem to coexist just fine," (second paragraph).

Bill Robertson
#5939

[Bitsyncmaster]

"They seem to coexist just fine," (second paragraph).

Bill Robertson
#5939

But they don't mix. So your compressor will not get oiled.

Why do you think they replace the oil if it works fine with R-12 and R134a. We should have just left the mineral oil in it.

[content22207]

Oil stays in the compressor. Oil getting picked up and carried around the system is actually counterproductive -- several times I have had to flush out people's evaporators when they clog them up with oil from those big cans of freon/oil mix (oil doesn't evaporate).

There's an SAE paper about R12 A/C systems converted to R134 with the mineral oil in place that finds no significant problems: http://papers.sae.org/940599 -- I bought the last SAE paper (spark plug gaps), so I'll let someone else buy this one.

#5939 ran with R134 and its original mineral oil until the front shaft seal began to leak (2002-2006). My Lincoln is still running R134 with its original mineral oil charge.

Bill Robertson
#5939

[Cory W]

This is what I took out of my old evaporator when I replaced every component refrigerant comes in contact with last year. The car has apparently been "converted" to R134A before I got it. Now, with a fresh clean system, it blows nice and cold with R134A.

I still have the jar if anyone wants samples...

[content22207]

Black death is caused by deteriorated rubber: http://www.aircondition.com/tech/questions/15/. That it is caused by R134 incompatibility is an urban legend. It just showed up coincidentally with R134 as new compressor and condensor designs came into use at the same time.

Now you see why I flush my system every chance I get, with a gallon of paint thinner every time. Old fashioned components (like ours) are imminently flushable. The fact that I am still running my original orifice tube (and accumulator, evaporator, condensor, *AND* hoses) evidences veracity of that methodology.

Owners are free to rip their whole system out and change it if they want, but simple maintenance sure is helluva lot cheaper and easier.

It never ceases to amaze me that DeLorean owners who meticulously sand each individual fuse in their fuse box won't do basic A/C maintenance. It's kind of like polishing your fenders but never changing the engine oil.

Bill Robertson
#5939

[Bitsyncmaster]

Oil stays in the compressor. Oil getting picked up and carried around the system is actually counterproductive -- several times I have had to flush out people's evaporators when they clog them up with oil from those big cans of freon/oil mix (oil doesn't evaporate).

There's an SAE paper about R12 A/C systems converted to R134 with the mineral oil in place that finds no significant problems: http://papers.sae.org/940599 -- I bought the last SAE paper (spark plug gaps), so I'll let someone else buy this one.

#5939 ran with R134 and its original mineral oil until the front shaft seal began to leak (2002-2006). My Lincoln is still running R134 with its original mineral oil charge.

Bill Robertson
#5939

So why did you use Ester oil? I guess if you flush it often enough you can keep the mineral oil.

[content22207]

Parts houses don't stock mineral oil anymore. I use Ester because I use mineral spirits as my flushing agent -- I don't know if PAG would react negatively with any residue.

PAG is also extremely hygroscopic (much moreso than Ester).

Bill Robertson
#5939

[content22207]

I've just returned from a 250 round trip errand. Burned the A/C the whole time. Nothing backed up, exploded, or otherwise failed to provide wonderfully cool air both ways -- I must be doing *SOMETHING* right (other than the compressor, every single inch of my A/C is factory original).

Bill Robertson
#5939