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From Sun Mar 9 16:22:06 1997
From: (Kenneth L. Potter)
Subject: Million mile Bimmer
Date: Sun, 9 Mar 1997 19:21:21 -0500

Okay, okay, I know I mentioned this before, but for our friends outside of the USA and for anyone who wants more detail, here it goes...

The March '97 issue of the Roundel has a story on a 1990 325i coupe that was a test vehicle for Mobil 1 and Mobil Super Unleaded.

The facts: Total mileage: 1,005,000 miles After break-in (1,200 miles) only 5W-30 Mobil 1 and Mobil Super Unleaded were used.

BMW maintenance and service requirements followed completely. Test run on an outdoor instrumented roll stand (to subject the car to changing weather conditions). Hourly speed cycle was 75% at 80-85mph and 25% at 50-55mph. The test was run over a 4 year period night-and-day schedule equivalent to 66 years of typical American driving. The only failures: 2 differentials, 1 drive shaft, 1 water pump and 1 automatic transmission. *No engine parts failed*. Fuel injectors changed at 680,000 miles because 1 showed signs of deposits.

After the test, the engine was removed and disassembled for inspection:

       "The engine was extremely clean and free of deposits. 
        There were no visible top-of-stroke cylinder ridges.
        Cam lobes and valve guides showed little wear and were in excellent
        operating condition. (The cam shaft rotated over a *billion* times during the test). 
        With 2 exceptions, all the engine parts were within BMW specifications. The exceptions were...
        The No. 2 piston ring end gaps were .004" over.
        Two con rod bearings were .0008" over."

After the tear-down, the engine was reassembled, the car was driven from New Jersey to Las Vegas and back, and then shipped to Europe for "display and touring purposes". BMW inspected the engine and issued a paper on the test.

Now I know skeptics would point out things like the fact that nothing is mentioned about cold starts and most engine wear occurs during that time. However, I think that all in all this is still very compelling and I personally will be switching to Mobil 1 oil at my next service. FWIW, I may end up putting the tear-down pictures on my web site.

Ken Potter
'97 tiA - Arctic Silver - still all original :)

Ken Potter                    |"If all of the ignorance in 
                              | the world passed a second         | ago... *what* would you say?"

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