djinferno1

I was looking trough my owners manual and I cant figure out what this is...

im guessing it should not be covered in grease?

E60I

That looks like a power steering fluid container. Make sure the outside are clean before you open it. You don't want to contaminate it.

djinferno1

thank you

H F

Mine too has a little build up around the cap. I noticed after I take my car on mountain drives when I carve the. S turns and really hit the corners hard , I get alittle leakage . I think it's from the breather hole and allows for the expansion of the fluid to escape when the fluid temperature rises from the ARS suspension workin hard pushing fluid thru the torsion bars in keeping the car level . I get some simple green a tooth brush and a rag , it cleans right up.

BimmerFan52

Agree with other posters. Clean carefully before opening.
Check CHF11S level as it may have been overfilled, or it may be low. The power steering system and Active Roll Stabilization torsional valve (if your car is equipped with the sport suspension) share the same hydraulic fluid. You don't want either system to be damaged by a low fluid level or fluid contamination.

When you state that it is covered in grease (or hydraulic fluid), it sounds like this is more than just a little fluid.

A reservoir can overflow because of either too high a reservoir pressure (return line) or foaming of the fluid due to air being introduced into the system.

A malfunction of the power steering pump can cause return pressure to be too high, or an obstruction of the return line can also increase pressure, with the result that fluid is forced from the reservoir through the hole in the cap.

Another possibility is that you have a pin hole in the line near the power steering pump and are sucking air, causing the hydraulic fluid to foam (air bubbles) and causing the fluid to rise to the top of the reservoir cap and overflow.

Clean the reservoir and then take it for a drive. If there is fluid on the outside after the drive open the reservoir and look in it with a flashlight. If you see a lot of air bubbles in the fluid then you are sucking air and will need to have the input line at the power steering pump checked. If there are no bubbles then it may be the pump pressure malfunctioning and the pump will need to be tested.