XJ6 Series 1 overheating,the crossover pipe is the usual culprit

The alloy crossover pipe at the front of the XK engine corrodes internally and restricts coolant flow. Symptoms are overheating in traffic with normal highway temperatures. The pipe looks fine from outside but is often 50% blocked with corrosion deposits. Replacement pipes are available in stainless steel for about $180 and the job takes a couple of hours. I replace them preventatively on every Series 1 XJ6 I work on. It's the single most common cause of XJ6 overheating that gets misdiagnosed as a radiator or water pump problem.