Oil Change Capacity '87 300DT?

[retmil46]

Have an '87 300D Turbo, 603.960 engine, has the side extension on the oil sump, and the remote air/oil cooler behind the front bumper. Has the original engine oil dipstick, black handle.

A few days ago, I took it in to the MB dealer in Hickory NC to have a one-time major maintenance done on it, with the idea of getting a good overall idea what kind of shape the car was in.

When he performed the oil change, the tech poured in the stated capacity in the service manual, 8 quarts, but apparently never checked the dipstick. When I came to pick it up, I checked everything over before leaving, and when I pulled the engine oil dipstick, the level was 1 1/2 to 2 inches over the max mark!

I grabbed the service advisor, he checked the dipstick himself, and immediately pulled the car back in the service bay to have it drained down. But both he and the tech were baffled why it wouldn't accept the stated 8 quarts, even allowing for the oil cooler and lines.

When I changed oil myself previously, on level ground and hot, level just at the max mark, the most that drained out was 6 1/2 to 7 quarts, and the same amount to refill.

A receipt in the glovebox from the PO stated the same amount for an oil change, 6 1/2 quarts.

The SA and tech were quite serious that even allowing for the oil cooler and lines, that engine should still have accepted 8 quarts to put it at or below the max mark. For the time being, I'm trusting the dipstick - I'd rather be a quart low than a quart too high!

Anyone have any ideas/info on this?