Automatic Boot

[ChrisE39]

Hi All,

Just wondering if anyone could provide some advice on the auto open boot / trunk function.

I have a 2002 E39 touring with the auto open boot - i.e. hit the button and it goes all the way up (or used to!).

Now when I hit the button, the boot opens and I can hear the motor whirring but nothing happens. Are these systems hydraulic? Any ideas what it could be?

I can still open the boot as normal (i.e. using my arm!) but it is not doing what it is designed to, though it sounds like it is trying to...

Thanks

Chris

[Roy in GA]

It is hydraulic. Is your pump unit low on hydraulic oil?

[ChrisE39]

Not sure - how would I check the oil level? Sounds like a real possibility.... What oil would it need? Sorry for the ignorance!

[Roy in GA]

The hydraulic pump unit I think is next to the rear left of the spare tire well. I think you may find a plastic fill cap and dip stick on it or near by. e39s list the hydraulic oil as either Pentosin CHF 7.1 or CHF 11S. Your owners book should tell you the correct one or it will say on the fill cap. Here is a parts picture from realOEM web site.

RealOEM.com * BMW E39 540i TRUNK LID HYDRAULIC PARTS

We don't get this trunk lid option in the US so I am answering based on my review of the BMW WDS and ETK disks.

[big bob]

There could be a system that disengages the auto boot motor to allow manual operation. Maybe it is stuck in the unengaged position.