High-mileage German performance cars aren’t exactly known for their reliability. That’s especially true for the BMW M5, of which every variant has its share of known issues. The first twin-turbo V-8-powered M5, the F10, has a handful of catastrophic problems that emerge as mileage builds. One of those problems killed this motor.
The I Do Cars YouTube channel managed to get ahold of this 4.4-liter V-8, codenamed S63TU for you BMW nerds, for a recent teardown video. With the turbos mounted in the valley of the engine and more hoses than we can count, disassembly is no simple feat.
Removing the turbochargers reveals a slow coolant leak, but surprisingly, the turbos themselves are in good shape. Taking off the valve covers shows similarly healthy camshafts, with only a few minor imperfections. Once Eric pulls off the heads, we can see intact head gaskets and undamaged cylinder walls. Still no signs as to why this engine suddenly locked up on the highway.
Peeling the oil pan away, Eric starts to find hints of damage. Metal flakes are floating in the leftover oil, w bigger chunks sitting in the pan. It’s only when the main caps that hold the crankshaft to the block are removed that we see the fatal problem: One of the bearings for the crankshaft has spun and fused itself to the shaft. It’s so bad that Eric can’t even remove the bearing to inspect it.
Even more eye-opening than the failed crank bearing are the rod bearings. While none of them failed, they were all heavily worn. This engine had around 103,000 miles on the clock when it failed, which isn’t all that much in the grand scheme of things. This is your sign, BMW M5 owners. Get those bearings replaced before they fail. It’ll save you a whole lot of cash.