Inside the L87 V8: Why GM’s Oil Pump May Be Killing Bearings

A bent pushrod and a lifter rotated 180 degrees inside its guide. That is what independent engine builder Dave’s Auto Center found after tearing down another General Motors L87 6.2-liter V8, the powerplant installed in Chevrolet Silverado and GMC Sierra 1500 trucks since the 2019 model year.

The physical evidence points to plastic lifter retainers failing under stress. Once that retainer gives way, the lifter spins freely. Metal shrapnel then circulates through the oiling system, scoring main bearings and polishing connecting-rod journals where a protective hydrodynamic oil film should exist. The teardown revealed damage on the number-one main bearing consistent with this exact sequence of events.

GM has faced multiple class-action lawsuits over the L87, largely focused on camshaft lobe wear and lifter collapse linked to the Dynamic Fuel Management cylinder deactivation system. Dealerships typically follow strict diagnostic trees before authorizing warranty replacements, leaving owners whose engines exhibit early-stage symptoms without factory support.

Dave’s Auto Center is now investigating whether the truck’s variable-displacement oil pump accelerates these mechanical failures. The pump reduces oil pressure during light-load driving and idling to meet federal Corporate Average Fuel Economy (CAFE) standards. Lower pressure means a thinner oil film separating the crankshaft journals from their bearings. If metal debris from a failed lifter retainer enters that thinned oil layer, catastrophic friction follows.

The proposed intervention involves reprogramming the variable oil pump control module to maintain higher baseline pressure regardless of engine load. Dynamometer testing on modified L87 short blocks is currently underway to measure whether sustained pressure prevents bearing degradation. The shop is also evaluating aftermarket steel or reinforced composite lifter retainers to replace the factory plastic components.

General Motors plans to phase out the fifth-generation small-block architecture entirely for its half-ton trucks. The 2027 Chevrolet Silverado 1500 and GMC Sierra 1500 will debut the sixth-generation family, featuring a 5.7-liter L76 and a 6.6-liter L78. Both new engines retain cylinder deactivation hardware required by current emissions regulations, making the ongoing research into lifter retention mechanisms relevant beyond the existing L87 fleet.