XSeries-forum

What is the item which is NOT numbered at the bottom of the picture with pipe 9 and 10 connecting to it?

Realise now the pic I put up isn't numbered. It's the item at the bottom, right of center.

The only thing I can find using Realoem and a late E53 4.6is as the search parameter is an ‘Auxillary Water Pump.  It only shows on the Heating & Air Con data....

It’s on this slide:  http://www.realoem.com/bmw/enUS/part?id ... 4116955122

I couldn’t find an exact match to the slide on Realoem though.

No idea what it’s used for, but my best guess is for Aux Heating where fitted.  Range Rover use the exact part number for that role.

Yes, that pointed me in the right direction, in my BMW fans parts list it's in the heating and air conditioning section as an additional pump. It's connected between the Header tank and the accumulator. Some weeks ago I was on here whinging about a buzzing noise that would disappear after switching off the heater fan, well, it's this pump that's making the noise, it must run all the time the fan is on.

Well, new additional (electric) water pump fitted and no more noise, I'm sure the interior heating has improved somewhat ie gets hot air quicker. Or maybe I'm just thinking it's improved cos I've had to spend some money.