I understand how oil testing can help a company running a fleet of trucks. But I don't understand how a 1-shot analysis can help tell us anything about our engines or the suitability of an oil.

Trucking companies send in samples on a routine basis. They analyse for suspended contaminants, wear debris and perhaps remaining additives. Results assist in predicting required oil change frequency and maintenance needs.

By tracking results over the life of a particular engine, trends can be established which can help eliminate costly repairs. Don't imagine many individual car owners would do that.

BTW Barry - Here in Ontario, I used to use Mobil 15W50 before an engine overhaul on our 300D (when it was readily available). But now use Mobil 5w40 Turbo Truck & Diesel. Buy in USA because prices here are crazy high! Low pour point should help with winter starting.

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Graham
85 300D,72 350SL, 98 E320, Outback 2.5

Will lifter noise happen with one cylinder at a time sometimes? I am pretty sure I've narrowed it down to lifter noise.
Should I be concerned enough to switch back to 15w40? I would rather not waste the stuff that's in there if wear is typically slow with these. I understand I might eventually need to do some lifter work but that's not really financially feasible right now.

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1992 MB 300D 128k
1988 Volvo 244 200k-ish

I recommended a four-pack of oil samples, not a 1-shot. However, even one sample can be valuable, as the lab will provide the "normal" values for comparison.

Attached is a sample of M1 5w-40 after 5000 miles of use in my '87 wagon with OM603. All wear levels are normal, soot was below 1%, indicating that I probably could have gone another 5k miles without exceeding the soot limit.

Attached Files

300TD oil test 27Aug2010.pdf (37.0 KB, 188 views)

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Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC