Porsche M48 (Cayenne V8)

Porsche's V8 for the Cayenne and Panamera — the 4.5 M48/00 and M48/50, then the 4.8 M48/01 and turbocharged M48/51.

⚑ Cylinder bore scoring is the failure this family is known for, and it is structural rather than a bad batch. The bores are coated rather than lined, and scoring on cylinders 2 and 6 in particular is well enough documented that it is a standard pre-purchase check rather than a rare misfortune.

Its tell is oil consumption with a rough cold start, sometimes a misfire code on one bank, and a borescope through the plug hole answers it in half an hour — before anything is stripped and before a car is bought.

The coolant pipes inside the V are the other known item on the early cars: plastic pipes bonded into an aluminium housing, in a place that requires the intake off to reach. The accepted repair fits metal pipes, and doing it preventively while the intake is already off for something else is what experienced owners do.

On the turbocharged M48/51 everything above applies with less margin, and oil condition matters correspondingly more.