It’s always important to routinely check and change your oil. It’s the lifeblood of your engine, after all, responsible for lubricating the complex combination of metal pieces that work together to make all that horsepower. Having too little oil can be catastrophic. But having too much oil is just as bad, as this teardown of an overfilled Jaguar engine shows.
Eric from the I Do Cars YouTube channel managed to get his hands on a 3.0-liter supercharged V6 out of a 2017 Jaguar XE sedan that failed because it was severely overfilled with oil. According to the salvage yard that sold the engine, nine quarts of oil came out of the pan when it was drained. Maximum capacity for this engine is just 5.7 quarts.
Teardown of the heads show signs something’s gone wrong. This engine has only been used for 66,000 miles, so everything looks relatively clean. But metal flakes in the oil filter and scarring in the cam journals point to catastrophic damage in the block.
Sure enough, once the heads come off, Eric finds the two forwardmost pistons are no longer properly secured to the crankshaft. He also discovers they’ve previously made contact with the head — something that’s not supposed to happen in normal operation. Taking off the oil pans reveals a ton of torn-up rod bearing material, including a few giant chunks. That explains the loose pistons, then.
Taking the pistons out reveals a bunch of burnt metal at the bottom of the connecting rods and a bunch of damage to the cylinder walls. When an engine is overfilled with oil, the crankshaft splashes the excess oil around in the crankcase, turning it to foam. When that foam is sucked into the oil pump it aerates the oil to the point where it can no longer lubricate the metal. The result is a bunch of friction and heat that, left untreated, will quickly kill a motor. And that’s exactly what happened here.
Take this Jaguar V6’s destruction as a sign to learn how to check your oil properly. Or you could end up with a bricked engine.