Rick's Free Auto Repair Advice

AC O-rings

AC O-rings for R-134a systems

Replacement Auto AC O-rings

When car makers used R-12 as the refrigerant and mineral oil as the lubricant in auto AC systems, they often used neoprene AC O-rings and gaskets. Neoprene and Buna O-rings worked well in those R-12 applications. But as R-12 was phased out and R-134a took its place, they found the neoprene and Buna O-rings didn’t hold up as well. So they switched to HNBR green O-rings.

What are Buna O-rings?

Buna o-rings (NBR or nitrile rubber o-rings) are similar to neoprene in composition and application uses. Another alternative to neoprene o-rings is HSN (highly saturated nitrile) o-rings that are compatible in automotive, air conditioning, and other low-temperature applications. The composition of these o-rings does make them a better choice for certain types of refrigerants that were developed after neoprene, specifically R-134a, and similar items made specifically to be environmentally friendly.

What are HNBR O-rings?

HNBR stands for Hydrogenated Nitrile (HNBR)

HNBR O-rings

HNBR and Buna O-rings. HNBR is green

o-rings, also known as Highly Saturated Nitrile (HSN). The material is a synthetic polymer made by saturating the double bonds in nitrile=s butadiene segments with hydrogen. The result is an HNBR O-ring that has superior heat, ozone, chemical resistance, and mechanical characteristics over standard Nitrile. HNBR o-rings do are a much better choice for use in R-134a auto AC systems.

©, 2020 Rick Muscoplat

Posted on by Rick Muscoplat



Custom Wordpress Website created by Wizzy Wig Web Design, Minneapolis MN