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Oil and Freon Questions

JohnM on Mon July 21, 2008 3:05 PM User is offline

I'm a new user and have a couple quick questions that I'm sure you guys can answer.

1. I've read about the differences between PAG and PAG DEC. What about Ester? Is PAG and Ester compatible within the same system? The reason for the query is because I have a 1996 Dodge truck that needed a small amount of freon added so I added a can of 134a "with oil" but the oil on the can was not specified.

2. I'm going to evacuate and charge a new system on a hot rod that I've built using all new components from Vintage Air. Which oil should I use and why? (Compressor is a Sanden).

3. I see at various auto stores that ID is offering regular 134a and a "synthetic" 134a that is twice the price and is supposed to perform better. Any validity to that claim?

Thanks!

mk378 on Mon July 21, 2008 3:19 PM User is offline

1. DEC PAG starts as PAG, then is further processed chemically to make the molecules more stable. It can be used interchangeably with regular PAG in factory R-134a systems. It's not the end of the world to mix ester and PAG but ideally you'd keep the same oil that was originally used. Who knows what's in that can? The only cans to buy are those with plain R-134a in them. Oil does not need to be added for a slow leak. Only if there is evidence that a considerable amount of oil has leaked out.

2. Use what the compressor manufacturer recommends, probably a certain viscosity of PAG. The DEC version is better. If the compressor comes with oil in it, drain that out and put back the same amount of new just before installing the compressor and closing up the system.

3. No. Buy the plain generic R-134a.

bearing01 on Mon July 21, 2008 3:37 PM User is offline

interesing... I thought DEC was just Double End Capped.

mk378 on Mon July 21, 2008 4:20 PM User is offline

It is. End capping describes the chemical change that modifies the ends of the PAG molecule, replacing an -OH with a more stable -CH3.

JohnM on Mon July 21, 2008 4:27 PM User is offline

Thanks, guys! So did Interdynamics just decide to put some 134a in a new can and call it "super-duper synthetic" and charge more for it??

bearing01 on Mon July 21, 2008 6:26 PM User is offline

Quote
Originally posted by: mk378
It is. End capping describes the chemical change that modifies the ends of the PAG molecule, replacing an -OH with a more stable -CH3.

ooohhh.. my bad. I thought it meant a second seal under the screw on cap. The DEC PAG I got from ACkits had the seal. The can/bottle of PAG I saw at Kragen Autoparts just had the screw on cap with no seal in under.

CCWKen on Mon July 21, 2008 10:22 PM User is offlineView users profile

Except for some of the basic liquefied gasses, all refrigerant is synthetic. I can't recall anyone just going outside and scooping up a handful of 1,1,1,2-Tetrafluoroethane.
DEC PAG is less hygroscopic than regular PAG.

-------------------------
Ken Kopsky

Custom Car Works
"Rules are for the guidance of wise men and the obedience of fools."

chris142 on Mon July 21, 2008 11:04 PM User is offline

Quote
Originally posted by: JohnM







2. I'm going to evacuate and charge a new system on a hot rod that I've built using all new components from Vintage Air. Which oil should I use and why? (Compressor is a Sanden).






My 1st choice would be Pag #46 and my 2nd choice would be Ester 100. I prefer Ester myself but since hot rods don't accumulate miles like a regular car the compressor will spring leaks before it wears out with #46 in it.

The teacher at the class I took claimed that #46 would allow the system to be cooler than thicker oils. He also said that Ester is a superier lube compared to Pag.

I stock 3 oils at my shop. #46 and #150 Pags. Anything that requires 100 gets Ester.

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