Royal Purple 15w40, 3400 mi, 1999 BMW M3

[GroovinPickle]

I've owned this car for a year and a half, but just got my first oil analysis done. The car does zero commuting and very few short trips. I drive it almost exclusively on the weekends. Some of those weekends involve autocrosses (I think this oil has about 40 runs on it) and occasional track days (maybe 150 miles of track duty on this oil). Although I used about half a quart of make-up oil, that was mostly a measure to reduce valve tick; it probably burned 1/4 quart in reality - well within spec for the engine.

Air and oil filters are both OEM. The air filter is less than 7000 miles old, and of course I change the oil filter with the oil.

I'm interested to hear any comments/suggestions. Here are the results:

1999 BMW M3
3.2L I-6 (S52)
Royal Purple 15w40
Miles on oil: 3363 (April 30 - November 26)
Miles on car: 44,093
Make-up oil added: 0.5qt

Al 6
Cr 1
Fe 15
Cu 3
Pb 0
Sn 3
Mo 119
Ni 0
Mn 0
Ag 0
Ti 0
K 2
B 14
Si 6
Na 2
Ca 4135
Mg 14
P 926
Zn 1182
Ba 1

Sus. viscosity 69.5 [69-78]
Flashpoint 400 [>420]
Fuel 1.0 [ Antifreeze 0 [0.0]
Water 0.0 [ Insolubles 0.3 [
Comments: "Nothing too unusual showed up in this sample. All wear around averages for this type of engine, which is a good indication of normal wearing parts. Universal averages show normal wear after about 4700 miles on the oil. Insolubles were low at 0.3%, showing good oil filtration. No anti-freeze was found, but we did find a minor amount of fuel. This level is below our problem range and my be normal if you do a lot of city driving or idling. Suggest running your next oil 4500 miles. Wear should still look good."

 

[ekpolk]

Thanks for posting the data. I really don't know much about this specific engine, but I'd have expected from the type of use to see more wear. As it is, it just looks like another healthy, well-kept mid-sized six cyl.

I am curious about one thing -- I thought the engines in the M3s called for that unusual 10w-60 oil? Am I thinking of a different car? If not, I'd ask why you deviated, but I certainly would not quibble with the results.

 

[GroovinPickle]

I do try to take good care of it - always allowing it to come up to operating temperature before I go over 3000 RPM and so on.

The S54 engine in the E46 (2001-2005) M3 is the one that calls for the 10w60 oil. The owner's manual for my car (S52 engine) actually says 5w30, which is what I run in the winter (it's a BMW-branded oil made by Castrol), but I think it's just too thin to be used at the track in 80, 90, or 100 degree weather.

The one thing I'm curious about is the traces of fuel found in the oil. As I said, I don't commute in the car, so I asked a fella who knows more than I do about engines what the cause could be. He explained a little about the job of the PCV valve, and how it was most effective when the car wasn't accelerating, since vacuum is a function (related inversely) of the amount of air that the throttle body is allowing in. So if the car spends a good portion of its life accelerating (at low vacuum), some fuel vapors may remain in the crankcase. Does that sound about right?

 

[t-squared]

I would think it's more from the full throttle running where the ecm goes into "give it all the fuel it can swallow" mode. Doing autocross, I'm pretty sure your engine is seeing plenty of closed throttle deceleration while still in gear.

 

[Al]

As mentioned..WOT throttle takes computer out of "closed loop" mode and "lean burn"/economy disappears.

Did you take oil sample very hot??

Nice report.

 

[GroovinPickle]

At the time of sample the oil was warm but not scalding. I believe I had just taken it for a ~20 minute drive in ~40 degF weather and probably let it rest 20 minutes by the time I actually got the front end in the air and pulled the drain plug. I let it drain for a few seconds and then took my sample. I left the cap off for a day (so the oil could cool) and then sent it off.

 

[scotth]

http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=3;t=002740

Here is my last report on my 1995 M3 for your reference.

 

[Al]

I never leave the cap off. Just put it in hot close the cape and forget it.

 

[ekpolk]

GP:

I would advise against doing the "cap off" thing. I have no idea how much this might impact sample accuracy, but one of the things you're looking for in a UOA is contamination by gasoline, which is pretty volatile. To the extent that the "cap off" procedure allows some gas to evaporate, you'd be compromising the accuracy of your results.

 

[GroovinPickle]

ekpolk: Noted - I'll just go ahead and cap it the next time around.