Originally Posted By: Carmudgeon
Originally Posted By: fdcg27
An e36 with the M42 predates any BMW oil standard.
I've used a variety of oils in my 318i.
I prefer Maxlife 10W-40 or M1 15W-50. The Maxlife was Nextgen and did contain moly, which is no longer used in the current formulation. I have a few FAR jugs of it left.
A 10W-40 blend oil seems to be perfectly adequate for the needs of this little engine.
I have a UOA of the Maxlife posted in August 2012 if you'd care to search for it.
Yup, by almost a decade. The M42 first appeared in 1989, long before LL-98 came into being.
BMW's viscosity recommendations ranged from 20W-50 (-10 to 50C) to 5W-20 (-40 to -10C), and those were for conventional oil. A 15W-40 or 50 would cover most climates.
Approved "Special Oils (low-friction)" covered -30 to 30C, and probably meant synthetics, but no viscosity range nor type was specified.
How much oil your consumes might dictate whether you go 0/5/10/15 on the low end, or to 50 on the high end, but a good 40 weight would be fine.
Over on Bimmerforums, the last updated list of BMW-approved "Special Oils" from around 2007 is posted in the Ultimate Oil Guide.
From what I could ascertain, the Special Oils standard was a mix of semi-synthetic oils, running intervals no longer than 9300 miles (the earliest E36's had an interval of 7500, before it was increased to around 9300 following Special Oils or the LL98 standard).
Special Oils were generally 10w50, 15w40 and 10w40
LongLife98 Oils are generally 5w40, 5w30
LongLife01 Oils are generally 0w30 and 0w40
Basically, if your car is later than 1995, it's computer will run the newer 9300k service interval, as opposed to the earlier 7500 mile interval. In this case, it is certainly advisable to go with a fully-synthetic LL98 or LL01 oil. Otherwise, you will be safe with the earlier Special Oils, or even conventional, as the service indicator originally was designed around conventional oils*
* BMW NA engines, such as the M50 and the M42 are considered to be "very easy" on the engine oil, even with the long service intervals. This comes down, mostly, to the very large sump (5-7qts), where US domestics and "sludgers," like the Saab 9-3/9-5 only take about 1-2qts. Its also because the engines aren't being pushed to the absolute limits. The older computer algorithm takes into accound Number of Starts, engine temperature and that sort of thing to work out the interval.
My car, which uses the older 7.5K interval, has not yet run a full interval, even though my driving is practically all-highway.