Originally posted by Southern_Son
Some may argue that you will notice leaks outside the engine after switching. ... This is because the oil is formulated to acquire a surface tension that enables it to gravitate and coat the inside of the engine. ... This property explains why you may see leaks.
My understanding was that the detergency inherent in synthetic oil has a tendency to dissolve any accumulation of carbon & sludge around gaskets and seals that provided a tighter seal until it was disolved, and along with the more efficient lubricity of the synthetic due to it's smaller molucules, it gets into spaces where the dino oil wasn't going. All of this is the sum of what may cause some engines to develop some external leaks.
Originally posted by DSinger
That is incorrect. They come prefilled from the factory with a 10W-40 synthetic blend (factory special prefill). Any ACEA A3/B3 oil will due from then on (I prefer Mobil 1 15W-50). I was not aware that they now mandate Mobil 1. Only cars that come prefilled with Mobil 1 are the AMG cars.
ALSO, NEVER CHANGE FACTORY FILL UNTIL AT LEAST 4,000 MILES! It's a special fill and filter for break-in. If you do, your car may not break in until higher mileages.
According to every conversation I have had with Mercedes, their dealers, mechanics, and other technicians, ALL current models since model year 2000 come from the factory with Mobil 1 as the factory fill.
And further, "break-in periods" for engines are usually 1000 miles, and the only oil ever used is a simple 30W. This period is used to allow the piston rings and valve faces to seat against their mating surfaces. However, due to the development of technologically near-perfect computer controlled milling and lathes used in the manufacturing of these engines, there is no "break-in" period any longer.
There is an initial 1000 mile point where the dealer wants to see the car to check fluids, wiring, and components, but the next time they want to see you after that is 10,000 miles later.
So, with all due respect, it would follow that the special oil and filter you make reference to do not exist. At least I have never heard of such things. All I have been told was that all of the cars simply come with a standard oil filter and Mobil 1 in them.
As for Mobil 1 0W40, I can buy it at my local Target or K-Mart stores. There is also an excellent oil made by Lubro-Moly that is a 0W40 called "SYNTHOIL ENERGY". Ask Phil at FastLane/PartsShop if he can get it, because they already handle Lubro-Moly
For more information on synthetic oils, search the archives, and/or go to these links: