Rattle/high idle when starting

[aldo1123]

Hey everybody I have a 2001 X5 4.4i. When I start my car it makes a loud rattle from underneath, it almost sounds like there is something loose under there and the RPM's race high but then settle down to a normal idle and the rattle stops once it is at a resting idle. Other than that the car seems to run fine. Any suggestions or thoughts??

[01X5Guy]

Is this all within a 2-3 second period or does it continue to rattle for a longer period of time. Mine will intermittently do that on startup and rattle on a high rev startup. Usually I have a low rev startup with no rattle. Im still trying to figure it out.

[aldo1123]

Yes it only happens for a 2-3 second period and most of the time I do have a normal start up but it happens enough to make me concerned.

[01X5Guy]

Ok cool - I'm along for the ride in this thread. Most feedback here will tell you it's normal and nothing to really worry about. They will mention Vanos knock, change your oil weight, wash and wax with Zaino, etc.. lol But that gives me little comfort and I'm not convinced the knock will not cause damage down the road.

[aldo1123]

So I shouldn't worry about it? My only worry is that it never happened before until about 3 months ago and now it happens daily

[dpgx5]

Could be something maybe on the belt pulleys? Open your hood and see if u hear it from there...

[01X5Guy]

Mine is a pretty pronounced rattle/knocking - Can even hear it in the cabin w/windows closed. Wonder if it's a timing knock, or the top end is starved of oil on startup, or a gremlin is just letting me know he's still in there. But like I said earlier.. it knocks on a high rev startup and that only happens about 25% of the total starts. Does yours knock even after sitting overnight? How's the oil level? Last oil change?

[aldo1123]

Oil was changed recently. Morning start ups are ok most of the time, it happens more for example, if I'm out somewhere and my car sits for an hour or so and when I start it after that amount of time it happens a majority of the time.

[aldo1123]

Just spoke with my mechanic. Sounds like it's definitely an oil pressure thing. I'm going to check my oil level and maybe try parking on an incline and seeing if that might change anything.

[01X5Guy]

Sounds like we are pretty much having identical symptoms. Can't wait to get this one resolved.

Originally Posted by aldo1123

Oil was changed recently. Morning start ups are ok most of the time, it happens more for example, if I'm out somewhere and my car sits for an hour or so and when I start it after that amount of time it happens a majority of the time.