R12 in gauges that have been used for R134a

[JHZR2]

Hi,

I have a nice set of US made gauges. They have a dial in them which is marked for R12 and R134a. I have them set up with the connectors for R134a.

I need to do some readings on a car that runs R12.

Is there a good reason why I cant use the same gauges? Im not keen on letting R12 and 134a mix, but the miniscule amount in the hoses may be irrelevant.

I dont use them regularly, it is just for routine checkups and some top-up of 134a if need be.

But since I need to look at R12 now, Im not sure if it is prudent to use the same ones.

Thanks!

 

[crazyoildude]

there are some r134 that claim they mix with both but i would just convert it to r134

 

[JHZR2]

Im not mixing anything. Im also not converting the car to R134a, as it has an R4 compressor, which isnt the strongest unit out there. It is an older car, so Id rather the lower pressures of R12.

All I need to do is either use the same gauge set that I use for R134a on the R12, or not.

 

[Chris142]

crack a line and bleed any refrigerant out. as soon as you open the line any refrigerant in the lines will boil and escape.

 

[heyu]

All should be fine ,,With freon being a gas/vapor your gauge hoses are dry after a couple days after they are used

 

[TFB1]

Originally Posted By: heyu
All should be fine ,,With freon being a gas/vapor your gauge hoses are dry after a couple days after they are used


Agreed...

Really once you purge the air out of the hoses, there isn't enough of the previous refrigerant left to worry about... Ten years ago you can bet AC shops were swapping gauges back and forth several times a day...

 

[demarpaint]

Originally Posted By: heyu
All should be fine ,,With freon being a gas/vapor your gauge hoses are dry after a couple days after they are used


+1 As mentioned once the air is purged you're GTG.

 

[Smoky14]

The oil is what can cause problems, small amounts, a drop, can react with the newer oil and turn to a gell. I'd blow out the lines just to be sure.
YMMV

 

[JHZR2]

Will blowing out get the oil out? Wouldnt the oil sit in there as a film on the sides of the tube and do just what you mentioned?

Is any appreciable amount of oil actually expressed from the valves when using the gauges?

 

[heyu]

Being in NJ and winter coming up think about this till next summer if you want ,I just got my 12 lbs cylinder and looking forward to changing all my cars to this

http://www.super-freeze.com/sf-409a-refrigerant-r409a-freon-replacement-30-lbs-equivalent-tank/

 

[tightwad]

When converting to R134, you can just add the ester oil or POA oil without flushing or draining the system. You should change out the accumulator, because this where most of the excess mineral oil collects. The new accumulator will have a dessicant compatible with R134. The remaining mineral oil will drop to the bottom of the condenser and evaporator and not cause a problem. This is the short-cut DIY method, probably frowned upon by techs, but I did it on my 1983 El Camino about six years ago and it's still working fine.

 

[L_Sludger]

Originally Posted By: heyu
Being in NJ and winter coming up think about this till next summer if you want ,I just got my 12 lbs cylinder and looking forward to changing all my cars to this

http://www.super-freeze.com/sf-409a-refrigerant-r409a-freon-replacement-30-lbs-equivalent-tank/

Can I come to your place and switch from R134a to that?

I'd love the additional power and better MPG.

 

[mechtech2]

Simply open the valved and let the old stuff flush out. [for a couple of seconds]

 

[heyu]

Originally Posted By: L_Sludger
Originally Posted By: heyu
Being in NJ and winter coming up think about this till next summer if you want ,I just got my 12 lbs cylinder and looking forward to changing all my cars to this

http://www.super-freeze.com/sf-409a-refrigerant-r409a-freon-replacement-30-lbs-equivalent-tank/

Can I come to your place and switch from R134a to that?

I'd love the additional power and better MPG.


I don't know of additional HP or MPG's yet personally from the switch over ,But in spring i am changing my cars over to 409

 

[Propflux01]

Originally Posted By: heyu
[I don't know of additional HP or MPG's yet personally from the switch over ,But in spring i am changing my cars over to 409



Let us know how well it works!!