There may be an oil leak condition after the harmonic balancer is removed or replaced on some 2015 Escalade models, 2014-2015 Silverado 1500, Suburban, Tahoe, Sierra 1500, Yukon models and
2014 Corvette, equipped with the 4.3L, 5.3L or 6.2L engine (RPOs L83 L86 LT1 LV3).

When reinstalling the harmonic balancer, a different bolt design may have been used than what was removed from the engine.

Gen 4 engines use a non-keyed harmonic balancer.
The only part of the crank that is keyed drives the oil pump.
The bolt has a friction material on the face.

It does not seal the harmonic balancer to the crank.

Gen 5 engines use a keyed harmonic balancer that can see oil pressure.
It uses both a 1 piece bolt and a 2 piece bolt and washer arrangement. It seals to the face of the crank.

If a Gen 4 bolt is used in a Gen5 engine, it will result in an oil leak.

Gen 5 and Gen 4 Bolt Identification

The bolts shown below are:

Bolt 1– Gen 5 engine
Bolt 2 – Gen 5 engine
Bolt 3 – Gen 4 engine

Bolt measurements are:

Bolt 1 – 1 piece Gen 4 bolt: 1.869 in. (47.5 mm) at the flange
Bolt 2 – 1 piece Gen 5 Bolt: 2.055 in. (52.2 mm) at the flange

TIP:
The LT1 engine dry sump uses a longer bolt due to the oil pump that is used on this system