AC O Rings

[oldretiredafguy]

Getting ready to button up the 91 Burb AC system up. Ordered O rings from LMC, and they sent the requested O rings. They are all black in color, then I realized the original PN's are for a R-12 system. We are converting the system to R-134A. Most of the O rings I see at parts stores are now green in color. Any difference between black or green color O rings?

 

[ali_c20]

I was told by a technician that the black ones often are neoprene or nitrile rubber and the green ones are hydrogenated nitrile rubber (HNBR). There are also blue ones. The green ones are compatible with R-134A. Since a few years also the black o rings are made from HNBR as there is no industry standard. You can't tell the difference which material is used. I would get green ones or ask for HNBR o rings to be safe.

 

[Finkaire]

HBNR, lot of work to have an o ring fail

 

[oldretiredafguy]

Thanks Alexander. I thought I had read somewhere (here on the forum, or another source) that the green ones were the correct color. Happened to call NAPA and asked them the same question. They sell vehicle specific kits for repair/replacement of all O rings, for $9-10. Costs more for the diesel to drive over there. The kit does not include the washers that seal the muffler assembly to the rear of the compressor, but they said to bring those in from the truck to match. Once I pick up the kit tomorrow, I will add the PN to this post for anyone else that is re-doing a Suburban with rear air to have.