February 21, 2013
GM 4L80-E and 4L85-E pressure regulator valve design prevents adequate cooler flow at low RPM and high pressure/demand conditions, which can cause overheat complaints. In ‘99-later vehicles, the factory EPC pressure was set high at idle, resulting in engine surge conditions. Sonnax oversized line-to-lube pressure regulator and boost valve kit 34200-36K provides a significant increase in cooler flow under low RPM and high pressure conditions.
Sonnax valve body layouts provide a detailed overview of individual units making it quick and easy to determine what’s available for the specific valve body you’re working on. See all Sonnax valve body layouts.
Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.