This bulletin applies to 2012-2013 Cadillac Escalades, Escalade ESV and Escalade EXT, in addition to Chevy Avalanche, Express, Silverado 1500, Suburban and Tahoe, and GMC Savana, Sierra 1500, Sierra Denali and Yukon.
Customers may experience a service engine soon light, a rough running engine and/or oil consumption. Technicians may find DTC P0300 set.
Inspect number 1 and number 7 spark plugs for fouling, as well as intake manifold runners for an excessive amount of oil. This can be an indication of oil pullover from the PCV system.
Clean the oil from the intake and PCV baffle. Check for possible PCV baffle leaks with the left valve cover removed. Check for possible PCV baffle leaks by plugging both the baffle’s small hole and square vent, then apply regulated air pressure through the PCV pipe and spray soapy water where the PCV baffle and valve cover meet to inspect for possible signs of a leak. If a leak is found, the valve cover should be replaced.
The new valve cover should also be tested before it is installed.