It's not simply magnesium, in actual fact the important bits are aluminium and magnesium is just used for the main bulk of it.Smartbear wrote:Hi, the n52 engine is magnesium not ally & that's not the reason for the electric water pump-it's there to reduce emmisions & increase power by reducing parasitic loss.Dietcokeman wrote:Yep I bought a car from this very forum last year for a friend as she loved my car. Car was well cared for and looked after, and had done 82k .........fast forward 2k miles and the pump failed . She took it to and Indy who charged her 650 for a new pump and thermostat . This was a 2.5si . The N52 engine being ally needs a higher flow pump hence the electric addition and additional cost, it's the engines Achilles heel to be honest other than that they are pretty good motors .
Rob
The N52 engine block is cast with magnesium and aluminum for the crankcase. Magnesium is used to save weight, however magnesium is subject to a greater risk of corrosion from water. Moreover, magnesium may tend to creep under load at high temperatures. Thus, magnesium in its pure form or as a conventional alloy is not suited for permanently conveying high loads and forces of the kind typically encountered in central components of the engine. Therefore, BMW combined the N52 block to use magnesium alloy for the crankcase shell, with an aluminum “inner block” to complement the magnesium disadvantages.