Coolant Leak at Rear of Engine - keywords bearing cap passageways

This PI has been revised to remove the BQM contact information and update the repair procedure. Please discard PIP3794.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Some customers may comment about a coolant leak coming from the engine compartment. Upon inspection you may find that coolant appears to be leaking in the area of the rear main bearing cap or outer rear of the oil pan.

Drain the cooling system and then remove the transmission assembly. Then carefully remove the rear engine cover (aka crankshaft rear oil seal housing) and inspect the black sealing material on the steel gasket at the coolant passageways (both left and right) for cuts or separation.

Engineering is currently working to identify the cause of the gasket material to separate. Until the cause is known, repair the vehicle by installing "paper" gasket P/N 24507388 and rear cover (housing) P/N 12585249. This "thinner" paper gasket and "thicker" rear cover were used in previous model years and will work on the 2006 model year "only" if used together. The bolts attaching the cover to the engine block should be reusable.

Note: Do NOT attempt to use the past model year "thinner" paper gasket with the "thinner" 2006 cover, or a 2006 "thicker" gasket with a past model "thicker" cover.

Before installing the new gasket, thoroughly clean (remove all oil and coolant residue) and inspect the machined surface on the engine block for smoothness and flatness. Also inspect for sharp edges around the coolant passageways and remove if found.

See SI for installation and tightening information. Refill the cooling system and check for leaks BEFORE reinstalling the transmission assembly.

As soon as the root cause of this condition is identified this document will be updated and /or a bulletin published.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.