R-134A Oil Charge - Yep another A/C? - PeachParts Mercedes-Benz Forum

86-300sdl · #1 06-11-2011, 06:08 PM

My A/C had not been charged / serviced for seven years until last fall when I put in 1 ½ cans of R-134a (12oz) till the pressure on the charge line looked good. Big improvement in cold air. What I did not do was add any oil.

Wondering if I should add a can (2oz) of this stuff (photo) Says it is compatible with all R-134a air conditioning systems (mine is converted to R-134a) including mineral / ester / & PAFG oils

Not aware of any leaks etc, etc. Systems seems fine. Just want to make sure it is lubed ok.

My thought if over the seven years between service I needed to add more R-134A maybe I also needed to supplement the oil.

Thanks

leathermang · #2 06-11-2011, 06:55 PM

I would not add oil unless you had some indication that you have lost some.....
If you wanted to have it drawn down, replace the receiver-dryer and add what the AC manual calls for ( or measure the amount in it ) to replace that oil I think that would be a reasonable 7 year maintenance procedure given how important the dryer is to keeping the oil from turning acid and eating away at the insides of the metal lines...

280EZRider · #3 06-12-2011, 10:38 AM

I don't see how it's possible to mix mineral oil with PAG. It's the same as trying to mix synthetic engine oil with mineral engine oil, and in the end it won't work. If you have ever looked at these two oils, you'll notice a huge difference.

I agree with leathermang, but if you're determined to add oil then you need to know what kind you have in the system now and because you're using R-134a, it's probably PAG oil. And if you are going to replace the R/D, you'll have to open the system anyway, so that would be the perfect time to get all the old oil out (if you're unsure what's in there) and replace it with PAG - if you are going to continue using R-134a. Don't forget new seals if you choose to do this.

86-300sdl · #4 06-12-2011, 01:30 PM

Thanks guys.

Heading out through the AZ desert in the morning, and will be traveling around the state all week. Reported to be 105*+ so I'll need the A/C.

Appreciate the advice. Glad I asked!!! But when I do service the A/C I will do it right as you suggest!

Thanks again!

leathermang · #5 06-12-2011, 02:06 PM

Only travel at night like the Bedouins .....
Then you only have to worry about drunk drivers about 2 am when the bars close and snakes by the side of the road if you have to change a tire...
We will help you keep on the straight and narrow when you start to work on it....