You have to remove the alternator and belts to get to it, so it would be a good time to tend to your belts/tensioners as well.

Also look into the PS reservoir and 2 hoses for leaks/cracking, they are on top of the OFH.

The links Gary (luvmyE5303) posted are spot on use those for reference.

So yes, it would actually probably be a good idea to replace the belts and tensioner pulleys, the power steering hose (and maybe reservoir), and the CCV and hoses, since you're gonna have so much off anyway... Oh, and while you're at it, put a new G.A.S. mil-spec o-ring on your DISA valve, and get the VANOS rebuild kit too... After all that, you'll have an M54 to last you another 50 years... :thumbup::thumbup::thumbup:

I recommend the full rebuild kit from GAS with the mil-spec o-ring, rebuild it before it fails! :)

It didn't last the first 50 years.....

As mentioned above, the #1 culprit is the OFH gasket.

I wrote a DIY for my E39 1998 528i below, similar procedure for the X5 3.0i engine:

1998 528I Oil Filter Housing Gasket & “Freeze Plugs” Repair (E39) - Bimmerfest - BMW Forums

Thanks for the help, I replaced the the oil filter housing on my yesterday today I'm going to pull of the lower shield and clean it all up. I hope this takes care of leaks.

Beg to differ. An oil leak does not mean a dead engine, unless of course you run it dry... ;-)



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My underbelly is looking "juicy" going to do the Oil filter housing gasket.

Why replace the tensioner pulley?
and what is the G.A.S. mil-spec o-ring??

The tensioner pulley should be replaced if your miles are over 100k, or if you can feel play in the pulley without the belt on. Since you're going to have the fan and belts off anyway to replace your OFHG, check the condition of all your pulleys, as well as water pump, to see if they need replacement as well.

The G.A.S. mil-spec o-ring is the military-spec o-ring sold by German Auto Solutions. Original o-rings on the DISA unit are known to get brittle and leak over time, and replacing the o-ring with a new one might eliminate a vacuum leak. Lots of differing opinions here on whether replacing just the o-ring is sufficient here, since there are other problems that can occur with your DISA that can be major headaches.

Hope this helps. Good luck! Let us know if we can help further! :thumbup: