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Originally Posted by DerekS I appreciate your good advice which you offer so frequently.
However, in the case of the 2008 Bluetec, the factory recommended service interval is 15,000 kms or 9000 miles, NOT 19,000 miles.
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The US due to litigation from DEALERSHIPS not using approved oils makes owners suffer with dumbed down service intervals. In Europe the same oils we use here are APPROVED BY MERCEDES BENZ to go as long as 19,000 miles as written in the MB Sheet specifications 229.5 and 229.51.
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Why do you suggest that "changing the engine oil EARLY can result in damage or poor break-in" ? What evidence do you have to support this statement ?
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In Lubricants engineering 101 it's called "Additive Activation" as well as pre-determined wear levels which result in PREDICTABLE wear rated REQUIRED FOR OPTIMAL ENGINE BREAK-IN. Changing an oil early results in INCREASED wear since the additives in the oil ARE NOT YET FULLY ACTIVATED and results in increased number of additive activation cycles during an engines most critical time of it's life. Oil addtives found in MB229.15 rely heavily on pressure and temperature to completely activate and placement of the additives in the high pressure regions of the motor. Changing the oil more frequently INCREASES WEAR RATES in the motor REDUCING ENGINE LIFE.
The picture below shows the region where the buildup of the additives prevents metal to metal contact. Early oil changes result in a reduced additive boundries between high pressure surfaces resulting in greatly increased wear rates where there would have been none had the oil been allowed to remain in the motor.
Diesel engines in particular use oil additives which disperse soot and prevent the soot particles from reaching a size that can cause wear or damage to the motor. Often these particles in the case of approved MB229.5 and MB229.51 oils will maintain the soot in the nanometer size range. Only if those particles are allowed to conglomerate into the 1-3 micron range with higher than 7% soot content will you begin so see an increase in wear. Again the additives in the oil prevent this polar attraction between the particles. Point being, with the correct use of approved oils the soot will simply remain too small to cause any harm to the motor and pass safely between metal contact areas within the thickness of the boundry of the lubricant.
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I have never heard before that premature oil change can damage an engine, quite the opposite.
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Spend some time in Stutgart with some of the folks at Mercedes in the R&D department and they will be happy to tell you all about it.
The Mercedes has a very advanced system which precisely monitors engine oil condition. In addition it monitors the driving conditions and start cycle conditions in addition to oil temperatures and load on the motor to add a predictive value to the FSS system. It's safe to say the car is in fact smarter than you are and vastly superior to anybody who suggests early oil changes are of ANY benefit.
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As far as a "run-in at the factory", why then are there specific "break-in" procedures written in the Owner's Manual for a car that has been, as you maintain, already "run-in" ?
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The initial run-in provides Mercedes with the chance to verify engine and systems operation. New engines require a VERY specific initial run which cannot be left to a human. The engine is run and loaded by a computer following a very rigid program to achieve an optimal break-in. Diesel engines in particular take a VERY long time to fully seat often requiring more than 60,000 miles before cylinder compression reaches it's peak. The first 1,000 miles require Firm application of power (engine load) but limited rpms to prevent glazing of the cylinders. After 1,000 miles the engine requires gradual increases in rpm's with higher engine loading. Don't forget that diesels run at 18:1 compression ratio's and push more than 23psi of boost pressure. This is not your average AMG motor that can be thrashed out the door...then again you won't find ANY AMG motor that can outlive any modern high performance diesel engine.
DB
