Chevrolet finds cause and solution for Corvette Z06 engine problem

By Gary Gastelu | Published August 21, 2015 |

z06-engine-oilIf you read my recent review of the 2015 Chevrolet Corvette Z06, you know it didn’t end well.

Oh, the car was a thrill. With 650 horsepower worth of stomach-churning acceleration, a top speed of over 200 mph and more lateral grip than a wall could provide, it was world class in all respects. Unfortunately, its monstrous, supercharged 6.2-liter V8 performed a dramatic act of self-immolation during some spirited laps at the racetrack.

And now we know why.

After bringing it back to Chevrolet HQ for inspection, the engineers determined that the likely cause was a piston connecting rod bearing that was damaged by debris in the oil that was left behind after tapping the threads for the oil filter. Once a piece gets jammed in there, it starts creating more debris, which keeps making things worse until finally … kablooey. In this case, it took out a few more pistons with it.



Several other engines built early in the production run exhibited similar problems, but Chevy is confident that it has solved the root issue. Nevertheless, it is now recommending that all Z06 owners change their oil after the 500-mile break-in period to make sure that it’s clear of any debris before any of it gets stirred up into the important parts during high-performance driving.

Pretty much the same thing happened when the non-supercharged version of the V8 launched in the Corvette Stingray, as documented by Car and Driver, but that has since been resolved, according to Chevy.

Less than 1 percent of the more than 9,000 Z06s sold since last fall (about a third of all Corvettes delivered since then) have had engine failures, and a Chevy spokesman says that they’ve all been covered under warranty.

Of course, if the folks at Chevy had paid better attention to their own notes, the test car might have survived. Last November Chevy sent out a technical service bulletin updating the oil change schedule on the Z06 engine, as well as Stingray motors equipped with dry sumps, to include a 500-mile change due to a non-destructive oil foaming issue caused by a silicone sealant on a gasket that clears up during the break-in period. For some reason, the 2,000-mile car never got this change.

The lesson: Always read the instructions.

(And my reviews.)

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