I saw a 2011 Land Rover LR4 for sale “that had a failure in the crossover pipe which caused the headgaskets to fail”. I normally work on D2’s but was interested in this but wasn’t exactly sure how a failure in the crossover pipe would make the headgasket fail or if the oil and coolant had just mixed. If someone could explain how the crossover pipe works and what happens when it fails that’d be great appreciated, thanks.