My 190E 2.6 uses 2-1/2 to 3 quarts every 3000 miles and last oil change I switched to Valvoline Max-life for high milage engines. The results were pretty good. I was down a quart after 1700 miles and now it's about 2500 and I havent't checked the oil yet. My oil light would come on before at 1400 miles and I would be down a quart and a half usually. I'm going to use the Valvoline again at the next oil change. Willdo the valve seals this summer. It has gotton cold here in Chicago.
Note: Tried the LUBRO MOlY OIL SAVER and the results were not measurable while the Valvoline was.
1990 190E 2.6
1996 Grand Voyager 3.3
1985 Mustang GT 5.0 5 SPD
1982 Suzuki GS 750T