GoWesty always replaces the engine water pump on every Eurovan VR6 we sell. The original pump fitted by VW had a plastic impeller that is known to fail. The problem with this particular failure is that it is much trickier to diagnose than you might expect. Unlike typical water pump failures that include noise or a visible leak, when the Eurovan impeller fails neither of these tell-tale symptoms exist. Instead, the pump just stops pumping. What happens next is a real head-scratching series of events... which we learned the hard way.
About ten years ago, we had a customer who had recently purchased a Eurovan full camper from us. We had gone through this vehicle from tip-to-tail, as we always do. It was a relatively low-mileage vehicle, and the water pump was not making any noise and showed no signs of leaking... so we didn't replace it.
During the customer's maiden voyage, she began to experience an unusual over-heating event. Everything seemed fine otherwise: no leaks, no engine noises, and the power was just fine. But her coolant gauge would start climbing and indicate that the engine was overheating. She pulled over several times, checked the coolant level, listened for noises—nothing. All was "fine." The vehicle cooled off, and she started charging along.
In very short order, she found herself on the side of the road again—and now she was in the company of someone "more knowledgeable," who assured her that it was just her gauge lying to her... which turned out to be very bad advice, indeed.
Long story short: The vehicle ended up back at GoWesty with a completely melted-down engine. Upon disassembly, it was clear what had happened. The plastic impeller had failed, and the pump simply stopped moving coolant through the engine. Confronted with this implausible failure, she had ignored the temperature gauge and had driven the poor Eurovan camper until it could go no further.
So there you have it—and why we have the fix: A brand-new water pump with a steel impeller. Don't leave home without it!