MartiniOlive
27-01-2006, 03:51 PM
Not long ago, my main water pump bearing failed and this caused the water pump pulley to go out of alignment and as a result the serpentine belt broke off. On taking the pump out, I found out that the impeller is made out of plastic and when the bearing failed, it hit the side of its housing inside the block and broke up. Sending pieces of plastic into the cooling system. I fished the bigger pieces out and tried back flushing the engine to get the smaller bits but can only get about half of them. Gave up and put it all back and it seems to be OK so far.
The new pump has a metal impeller but I don't think that's the main problem. My opinion is that the water pump is poorly designed. The bearing should never be allowed to fail like this and allow the pulley/impeller to get out of alignment. The worst I've experienced in the MKI (and other cars) is a leaky pump or a noisy bearing.
I've read that a similar water pump is also used in 1.8T but with worst consequences. The water pump is driven by the timing belt and when it fails, the cams and the crank can get out of alignment with the worst case senario of piston and valves making contact. One hopes that VW have redesigned the pump in the MKV.
The new pump has a metal impeller but I don't think that's the main problem. My opinion is that the water pump is poorly designed. The bearing should never be allowed to fail like this and allow the pulley/impeller to get out of alignment. The worst I've experienced in the MKI (and other cars) is a leaky pump or a noisy bearing.
I've read that a similar water pump is also used in 1.8T but with worst consequences. The water pump is driven by the timing belt and when it fails, the cams and the crank can get out of alignment with the worst case senario of piston and valves making contact. One hopes that VW have redesigned the pump in the MKV.