My K75 has 134 000 on the clock. Last winter i repaired waterpump, replacing all the seals and drive shaft. Only after 1700 kms the engine started squeaking on idle. The squeak is only heard on idle when engine is hot. With cold engine and/or higher rews there is no squeak. Video below is not mine, but the squeak is equal. As far as I know, the timing chain and sliders has been replaced at 78 000 kms, but of course I cannot be sure about the present 134 000 kms, there has been two owners in between. Any ideas? Waterpump again? Timing chain sliders?

Hi mek,use a rubber tube to listen with more accuracy for the source of the squeak
OR hang a mouse trap on and see what you catch

My friend lent me his stetoscope yesterday. The squeak seems to come from water/oil pump, so coolant out and pump off again.

Hi mek,If there is no oil/water contamination or oil leak i would be tempted to leave it.maybe a seal softening product might help not a lot of mileage to warrant a strip down

I unassembled the water-/oil pump. I cannot found a clear reason for the squeaking sound. Pump does not leak, neither oil or coolant. Both seels look fine. Impeller was still a bit stiff to turn by hand. Some marks can be seen on impeller shaft gearing and oilpump case.


I would doubt for some other part to be broken, if the squeaking sound wouldn't so clearly come from water pump cover. When I listened with a stetoscope with metal pick, the loudest squeak came from water pump cover, next loudest from water pump case. From Timing chain cover or motor block the squeak was hardly hearable.

After thinking the problem my quess is, that the water seal is very difficult to assemble right without the BMW special tool. The pump is made from aluminium and the shaft from steel, so the pump expands more in heat than the shaft. Thus the seal gets more tight when the engine heats up. In my case it caused the squeak. I sent the pump for repair to http://www.equipmentbau.de/index2.html and got it back wery quick. Now it works ok.