Which oil for hi-mile MB inline 6?

[opposite_locker]

'97 e320 with 243k has run on Mobil 1 its whole life (10w30, 15w50, and recently 10w40 HM). Engine burns no oil, and leaves a single drop on the driveway every few nights from a seeping timing cover & head gasket.

Cold temps aren't really an issue here in the central valley (30 deg - 110 deg).

Which of the following oils from my stash would you run in this car for the next change?

German Castrol 0w30
Mobil 1 0w40
Mobil 1 Turbo Diesel Truck 5w40
Mobil 1 10w40 HM
Mobil 1 15w50

Was also thinking of a Mobil 1 5w40 mix with equal parts of 0w40, Mobil 1 Turbo Diesel Truck 5w40, & 10w40 hm...

 

[addyguy]

Why make it confusing? Just keep using what got it to 243k!

 

[JHZR2]

I'd put rotella 5w-40 in there. I'd do with a 5 or 10w-40 regardless, personally.

 

[mcrn]

If you just recently started the Mobil 1 High Mileage oil I would stick with it for a little longer. JMO.

 

[Geonerd]

You said it, use one quart of each!

 

[opposite_locker]

Upon further inspection, I have exactly enough 10w40 High Mileage left for another oil change...might have to try it alone one more time. After than, will likely go back to 15w50 or try out Mobil 1 Turbo Diesel Truck 5w40.

Anyone know how long the effects of "high mileage" oils tend to last? For example, if a "high mileage" oil decresed oil loss by 75%, will that effect continue after switching to another oil? Or will I have to continue High Mileage oil use to keep the seals "conditioned"?

 

[ARB1977]

Im guessing depending on how bad the leak is. Get the timing belt cover fixed...that will solve your issue.

 

[opposite_locker]

Leak is very minor, and doesn't require any topping off between 7500 mile OCI's.

Will post my Q about High Mileage oils on the main oil forum...