I had a reverse problem. I've got the right thermostat for my 190D, but I bought the seal from a stealer. You've guessed it- he sold me o-ring seals (whole bag of'em), instead the one that fits around the stat. he he, ain't the life fun??
1985 190D 2.2l Sold-to Brother-in-law
1996 Mustang 3.8l -"thinks it's a sports car"
1988 Grand Wagoneer - Sold (good home)
1995 Grand Cherokee Ltd -"What was I thinking??!!"