WATCH: GM 3800 V6 Engine Teardown Shows How Faulty Gaskets Can Spoil A Reliable Engine

The pistons were likewise in good condition, except for a few wear. However, the crankshaft had corrosion, also due to the coolant leaking into the engine.

While the GM 3800 is praised for its reliability, Eric concluded it had a “not-so-wonderful” intake manifold gasket design. As seen in this teardown, the coolant leaked once the gaskets became faulty, resulting in expensive repairs or a complete engine replacement.

If the owner observed a proper maintenance routine, the GM 3800 could last for even up to 350,000 miles before it starts acting up. Then again, the Grand Prix where it came from was left untouched for nine years, hence, the early demise of this V6.