The mysterious disappearing oil
 

When I had my 1993 300E2.8 into the dealer for a new head gasket and timing chain, they generously threw in a free oil (7.5 quarts of 15/40 castrol, according to the shop supplies list) & filter change at 161091 miles.

Now, a little over a month later and at 162618 miles, the oil level warning lamp has come on, and I'm down to the bottom of the dipstick.

Where could 7+ quarts of oil have gone in 1500 miles? the coolant is straw-coloured and free of oil, there's no drips on the driveway or on the bottom engine cover, and no blue smoke from the exhaust.

Where could the oil be going? The car did leak oil before the head gasket replacement, and I'd hoped it would go away with the new gasket. Should I be regretting not getting my valves done when I had the head off last month?

Well, the questions is really where did 1 quart go? Full to add oil is about 1 quart.

I suggest you top off the oil, then monitor the level. It is possible that the shop charged you for 7.5 quarts, but did not actually fill the oil to the top mark. If they were 0.5 quart short of a complete fill, you might be showing add oil at 1,500 miles, or using oil at 1 qt per 3,000 miles, which is nothing to worry about.

Let us know.

Yup, I'd bet on it. Pull the spark plugs. If any (or all) are oil-fouled on one side, it's a sure sign that oil is coming in to the cylinder through the intake valve(s).