New member 07 4.8

[Entropy]

Welcome!

In addition to the valve cover and timing chain covers, your oil thermostat housing gasket is probably leaking. They leak eventually on all N62 engines. Best to replace it while you’re in there.

Full cooling system refresh should be next on your list (WP, tstat, hoses, and I’m a big advocate of the BimmerFix coolant pipe stent kit). Also do spark plugs while you have the valve covers off.

P.S. I have an ‘07 4.8 as well (108k miles now). It has never left me stranded and has never had an unplanned repair. You just have to be OCD with preventive maintenance and fluid changes. Also consider servicing the differential fluids and p/s fluid (Pentosin CHF11S).

[rbryantaz]

Originally Posted by Entropy

Welcome!

In addition to the valve cover and timing chain covers, your oil thermostat housing gasket is probably leaking. They leak eventually on all N62 engines. Best to replace it while you’re in there.

+1. I just the oil thermostat gasket on my 2007 X5. The job is doable from the top side once you remove the radiator fan and alternator. It isn't as bad as it looks at first but you have to do it all blind by feel.

Only after I bought the new gasket I found that rockauto carries this gasket from MAHLE:

MAHLE B32856 Fluoroelastomer

This is listed as a fluoroelastomer (generic name for Viton).

If it is really Viton then it is likely a better gasket than stock. So it might be worth ordering that gasket. Note I also saw a thread where some places list this part number incorrectly as B32855 which is not the correct gasket for the oil cooler (missing the center divider).

I also ordered the BimmerFix stent even though my pipe had been replaced by the previous owner. Jeff at BimmerFix has been great to work with and provided me a smaller stent to match the aftermarket pipe (likely URO which is a thicker pipe with a smaller inside diameter). The kit isn't super cheap but he does a great job of supporting it and I was happy to pay the money for it. I am just doing this as preventative maintenance while I change the waterpump and pulleys. Better to add the stent now while it is apart and never worry again than have it break down later....

Pulleys...

I may have a source for genuine INA pulleys without having to buy the complete and overpriced tensioner/pulley assembly.... The X5 changed the 4.8i belt setup to be 7 rib making it unique.... This was likely done to handle the larger alternator and the large power steering pump on the adaptive drive X5s. This resulted in the replacement pulleys being way too expensive for the X5 4.8i.

The price of the AC tensioner pulley is particularly egregious at $100+ and it is actually harder to change the pulley plus bracket than just the pulley.

I have the AC pulley replacement figured out but still need to verify that my replacement main tensioner pulley is a match. The deflection pulley is available at a slightly inflated price but can be found for about $60 so it isn't really worth trying to source replacements for it unless I can offer it as a full kit.

If I am able to source the main tensioner pulley I might start selling them on ebay or through my webpage.

If I buy the pulleys in bulk I might be able to offer them for a price that makes it worth my while and still saves everyone money.

-Rich