grinding noise from engine when idle
 

So another question.. just parked and i hear a slight grind/whirl when idle.
The fan is fine as it comes slowly on and slowly off, it seems right inside the motor. I have 78K miles on the odo and no known issues, i.e. no CEL, no shakes, temp is normal and drives smooth.

I am thinking maybe water pump? or no?

thanks for any opinions here.

You may want to check your fan/clutch assembly. The sound I was getting when mine went bad, was also like a grinding noise from the engine. I am sorry, but I don't know a way to test it. I just replaced mine and the grinding sound went alway.

How much did that cost you? I dont assume that would be covered under CPO warranty though.

One time this happened to me, it turned out the steering pump was bad.

I got it from this guys;

BMW Parts - Discount BMW Parts - BMW Auto Parts - Online Catalog - Free Shipping - RM European Auto Parts

It should be covered under CPO.

Unfortunately, the fan clutch is no longer covered under CPO for 4.4 engines.

good info here, i will stop by my indy sometimes this week.

Last saturday, my 07 X5 3.0si had a continuous humming sound under the hood (i don't know if the sound you were referring as grinding/whirling sounds are the same as I described as humming). It started slowly and when reved up to 3000 rpm, the sound became louder (even from the inside the car), more when I got out to the front of the vehicle. Also, noticed the car is holding back even when accelerating gas pedal. It appears the aux fan when I lifted the hood up. I drove about 15 miles freeway (with the continuous whirling noise of the fan) when the NAV showed "engine temp is high, drive moderately, etc." So i stopped and turned off the car for 15 mins. I decided to went back home sensing there's something wrong and about less than 2 miles to my house (after exiting freeway), the power is decreasing even with gas pedal pressed and the NAV showed "engine overheated, turn off vehicle, etc." Waited for 15 mins and since house is so near, i was able to drove the car home. Any ideas what went wrong? The car is now in the garage waiting for Monday for a tow truck to bring it to my indy mechanic.

The eletric waterpump most likely failed.

Electric water pump??? The 4.4L engine has a mechanical water pump driven via accessory belts.

BTW....I've got 109k miles and my engine started making the so-called grinding sound. I've pin pointed the noise to the water pump bearing(s).