Oil for a high mile X5

[BitchinManWheels]

Hey y'all! I have a '07 X4 4.8i with 150k miles. My mechanic puts in BMW Twin Power 5w30 but I think it might be time for a change (pun).
What do you all think about a) high mileage oil and b) higher viscosity?
High mileage oil for the additives to refresh seals (so they say) and formulated for high mileage engines (whatever that means).
Higher viscosity, moving from 5w30 to 5w40, because the therory all of the joints are not as tight. The higher viscosity "stays" in those loose cracks/joints. Both viscosities are acceptable according to my owner's manual.
Thanks for the input!

[BitchinManWheels]

Answering my own question 3 years later...
Pennzoil high mileage platinum 5W30 seems to be doing well!
It's the same company who makes the BMW branded oil so I figured I'd go with this plus the "high mile additives".
Before when using just the BMW Twin Turbo I was burning through a quart of oil every couple of weeks and a bit of coolant (very concerning).
After a year using the Pennzoil my coolant is stable and the oil requires fewer top offs.

[chemist_slime]

Good to know, thanks for the follow-up!

[Lviv777]

Have you given 5w-40 a try?

[BitchinManWheels]

Originally Posted by Lviv777

Have you given 5w-40 a try?

Yes, when I lived in Arizona 3 years ago.

[OnlyGerman]

Are you using any oil stabilizer?

[BitchinManWheels]

Originally Posted by OnlyGerman

Are you using any oil stabilizer?

No, just this oil alone.
Have you had any luck with oil stabilizers?
I see Lucas Oil makes one specific for high mileage engines.

[OnlyGerman]

Originally Posted by BitchinManWheels

No, just this oil alone.
Have you had any luck with oil stabilizers?
I see Lucas Oil makes one specific for high mileage engines.

I've been using it on my n62 550 due to the smoke (valve stems). If everything is good on yours, I wouldn't add unnecessary stuff in it.

[Thecastle]

There has been some debate as to whether adding seal softeners as a preventative is a good idea on the cars to extend valve stem life. I've known folks who have been adding AT-205 to avoid the valve stem problem.

P.S. I had a 2008 4.8i, loved the sound of that engine, especially on cold starts. Its one of the things that sold me on the car, plus the power. Sounds much better than the turbo 4.4's. Mine did develop bad vavle stem seals and smoked like bat man, tired a lot of additives, and found at-205 worked the best on my engine. It eliminated the smoke for me.