'98 BMW 740i Quandary

[ProfPS]

A co-worker has '98 740i (4.4 v8 engine) w/ >100k mi and is planning his first DIY OC. He can't find the oil spec in the owner's manual and a dealership parts dept rep said to use 5w30 syn or 15w40 conventional, and he has decided that he wants to use Mobil 1. Which Mobil 1 oil grade would you use?

His OCI will be 7-10k mi, mixed city/highway driving in the northeast.

 

[addyguy]

Car is out of warranty, so it doesn't really 'matter' what he uses, ie. sticking to the BMW 'spec.'

If he wants to use M1, can't go wrong with any of their 40-weights...

0W-40 is an obvious first pic, but Mobil 1 Turbo Diesel Truck 5w40 or Mobil 1 High Mileage 10W-40 would be good options as well. If he's looking for something a little more inexpensive, Rotella T6 5W-40 would work well.

 

[Quattro Pete]

Originally Posted By: ProfPS
A co-worker has '98 740i (4.4 v8 engine) w/ >100k mi and is planning his first DIY OC. He can't find the oil spec in the owner's manual

Any LL-01 oil will work, if you do want to stick with BMW-spec'ed oil. From the Mobil 1 stable this would mean Mobil 1 0w-40, but other oils which the previous poster mentioned should work fine as well.

By the way, your friend's engine code is M62:

 

[d00df00d]

Originally Posted By: ProfPS
A co-worker has '98 740i (4.4 v8 engine) w/ >100k mi and is planning his first DIY OC. He can't find the oil spec in the owner's manual and a dealership parts dept rep said to use 5w30 syn or 15w40 conventional, and he has decided that he wants to use Mobil 1. Which Mobil 1 oil grade would you use?

His OCI will be 7-10k mi, mixed city/highway driving in the northeast.

Mobil 1 0w-40 for sure. Great multi-purpose oil. No reason to use an oil that doesn't carry the approval.

 

[JHZR2]

Usually there is a temperature/viscosity chart for BMW engines. I would run Mobil 1 0w-40 as my oil of choice for that engine. You could consider Rotella syn 5w-40 or similar oils (castrol 5w-40 for example).

If specs are important, you likely will want the LL-98 or 01 spec. IIRC, LL-04 is not suitable for any BMW gasoline engine use in the USA.

 

[Trajan]

Castrol 5w-40, A3/B3 LL-98

Mobil 1 0w-40 A3/B3 LL-01.

I've used both.

 

[ProfPS]

Thanks for your responses. Everyone confirmed my choices which were Mobil 1 0w-40/5w-40 or Rotella 5w-40.

 

[Craig in Canada]

Originally Posted By: ProfPS
A co-worker has '98 740i (4.4 v8 engine) w/ >100k mi and is planning his first DIY OC. He can't find the oil spec in the owner's manual and a dealership parts dept rep said to use 5w30 syn or 15w40 conventional, and he has decided that he wants to use Mobil 1. Which Mobil 1 oil grade would you use?

His OCI will be 7-10k mi, mixed city/highway driving in the northeast.


That M62 engine is not hard on oil, and likes it on the thick side. I'd look for Rotella T6 if it were mine.