BMW E65 coolant pipe and water pump flange leak
E65 leaks coolant from the front of the engine - what is the cause?
On the N62 engine, a typical cause is the coolant pipe (telescopic pipe) running through the middle of the engine leaking. The coolant often drains out as the engine cools down, and the leak stops once the engine warms up. The fault is a known defect in engines built before 9/2003, but it also occurs in facelift models.
What else besides the pipe can the leak come from?
The coolant can also come from under the water pump flange, through a hole in the front of the engine. In that case the expansion tank empties and coolant gushes out while the engine is running. The leak point cannot always be found without removing the belt.
How is the coolant pipe repaired?
The pipe can be replaced without lifting the engine by removing the water pump, the intake manifold and the part of the housing behind the pump. It is worth replacing the gaskets, water pump and belts at the same time. Replacing the original fixed pipe requires removing the engine from the car, so the aftermarket pipe is easier to replace.