Oil Type
Question: Do I have anything to worry about. Should I get an immediate oil change replacing the 15W40 with synthetic 15W50?
I am particularly worried since the Check Engine light came on a day after the oil change.
Thanks in advance for your reply.
Mercedes is now recommending Mobil/1 for all models. The check engine light may or may not have anything to do with the oil change. One reason it can come on is if you bought gas and didn't replace the gas cap tight enough. If the gas cap is on correctly and the check engine light comes on everytime you start the car, I would take it in for service.
A 5w-30 weight oil has additives that resist "thining out" as it gets hot. It starts out like a "cold" single weight 5 and as it gets hot, it acts like a "hot" 30 weight oil. All the time, as it is getting hot, it still is "thining" out or decreasing in viscosity, just not as much as a single weight oil does.
If you changed from a petrolium based oil to a synthetic oil, the superior detergents in the synthetic oil may disloge "false oil plugs" that were keeping your gaskets from leaking. This happended to me twice before with older MBs, so I do not change TO synthetic. I have never had much luck with the "Stop Oil Leak" products that try to expand the gaskets, or try to block the leaks.
Check your ambient Temp guide in the MB manual for proper oil weights for SF.
Good Luck.



