M54 water pump help required

Post Mon Aug 27, 2012 7:12 am

Not E30 but with the wealth of BMW knowledge on here.....

My E39 ate its waterpump on saturday (nothing strange there) but despite clearing the impeller debris from behind the pump after removal, there's still quite a lot of "bits" missing, which I really don't want circulating round the system with the new pump in place.

So what do I need to take apart to see where these bits are resting ? Thermostat housing ?

If backflushing is required, where to I inject the water in order to expel the bits from the pump hole? I don't want to get the flow wrong and push the debris further round the system.

Any help appreciated.

Post Mon Aug 27, 2012 8:45 am

The bits will have either dropped into the block or found their way into the rad, you can flush from the back of the head forward. There is also a drain on the RH side under the manifolds. Flush the rad out of the car from the RH side as any bits should be trapped in the LH tank

Post Mon Aug 27, 2012 9:26 am

Hmm, I was hoping not to have to take out the rad... but needs must when the devil vomits in your kettle....

Flushing from the back of the head would be similar to an M20 I suppose, from the heater matrix hose stub on the back of the head ?

Post Mon Aug 27, 2012 9:29 am

clipper wrote:Hmm, I was hoping not to have to take out the rad... but needs must when the devil vomits in your kettle....

Flushing from the back of the head would be similar to an M20 I suppose, from the heater matrix hose stub on the back of the head ?

Fooking classic quote that one

Post Mon Aug 27, 2012 6:05 pm

The bits are normally residing around the front cylinder - if they fail completely there's not a lot of coolant moving rearwards. Use an opened out wire coat hanger to fish bits out. Fairly unusual for one to completely fall to bits, but they're all 10+ years old now I guess. I took one out of a 1996 P reg 523i that I put a new rad in last week and it was still the original.

Post Mon Aug 27, 2012 10:08 pm

Sounds like a good plan. The shaft had dropped so far out of the pump that the belt had jumped off the pulley, so no,there wouldn't have been much pumping action taking place.