Quote:
Originally Posted by mpolli
I believe the important number to look at in order to answer this question is the TBN. If you went to Blackstone then he should have provided a "summary" of the results with an opinion of the miles left based on the TBN. That is how I remember it anyway. Doesn't the TBN test cost extra?
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I got the sample through MBCA member George Murphy. the TBN did cost $6 extra. He said that fleet managers replace their oil when the TBN reaches 1/2 its original value. In the case of Mobil one that would be 11.3/2 or 5.6 since I have about 9k on this oil I'm losing TBN at a rate of 4.3/9k or about 0.5 TBN per 1K that would say I have about 3K more miles on the oil. That works out to 12K. Maybe the guys at Mercedes know what they are doing after all. Having said that George Murphy the MBCA tech guru recommends 6.5k oil changes. I spend my life doing engineering calculations and it is hard for me to go against the data and follow his recommendation, though the 2009 10k oil change posted above gives me pause.