Q--I own a 2000 Lexus GS300 and have my oil changed at a national retailer. The oil capacity of the GS300, as given by the owner’s manual, is 5.7 quarts with a filter change. In spite of my instructions, the individual who changes the oil often puts in 6.0 quarts. When I check the dipstick after the car has been idle for a while, the dipstick shows the oil level above the “full” mark. Is this amount of overfill (.30 quarts) potentially damaging to the engine?
A--Although you should maintain the oil level in the area indicated on the dipstick, it is most critical maintain to keep the oil level above the low mark to prevent possible engine damage. Having the oil slightly above the full level will not have any negative effect on the engine. A significant overfill amount (one quart or more) may affect engine performance, but is less likely to cause damage than a low oil level.