Overfill
 

I have a 98 E300 TD. What engine damage can occur if there is an overfill of half a quart to a quart of oil? The oil filler cap says you "must not exceed the max fill mark or engine damage can occur."
Thank you,
RSL

To high an oil level in the crankcase will let the crankshaft churn the oil to foam. This will result in oil pump starvation, which means your engine won't be properly lubricated. Overfilling can also lead to high crankcase pressure, possibly leading to oil seal leaks.