Quote:
Originally Posted by 240Joe
How about changing the oil per the manufacturer's recommendation and putting the $40 in an envelope to be used for real needed repairs. I know this won't solve your psychological need to "work" on your car, but maybe you can just reach under the hood and get some grease under your finger nails, and maybe rub some in your hair for that real "I worked on my car" feeling.
I've never had a engine breakdown due to oil related issues either, and you don't want to hear about my oil change interval.
Using one brand of oil over another is another load of horse poop, encouraged by gigantic marketing budgets. As long as it meets the SAE rating your car needs, you're good to go.
All IMHO, of course.
 |
I have to butt in here a bit. Mercedes-Benz does not care about SAE, nor do they spec any oils based on any SAE specifications. Mercedes has oil specs based on their own test criteria, I believe the spec for most modern MB's is the 229.5. It will be specifically listed on the bottle of approved oils. The Lubrizol tool below shows some of the differences in different specifications in a neat chart to help visualize. Also a link to a list of MB approved oils for specification 229.5.
dataStack
MB 229.5 - Multigrade engine oils (Specification 229.5) - Mercedes-Benz Specifications for Operating Fluids
Quote:
Originally Posted by MBlovr
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.
|
Let us also not forget that TBN depletion is not linear. Just because it may appear at first testing that it's 'using .5 TBN per 1k miles', it does not mean thats how it has trended since new. Perhaps it sheared 1 TBN or more per 1k miles early on, and tapered down as the oil settled in for the rest of it's useful life? Maybe it's the opposite, perhaps it's very low at first, and as it gets older, TBN depletion will ramp up to well over 1 TBN per 1k miles until the end of ti's useful life. You can't make these kind of blanket statements, as without data or consistent oil analysis over time, there's no way to really know.
07-06-2014, 07:39 PM
Linear Mode
