So my indie says I have a leaking heater core on my '90 190E when I took my car in last week. The tech showed me a slight drip near the passenger-side tranny pan. To my horror it was GREEN! I thought I told them last time I had the radiator changed to put in M-B coolant and even provided a bottle of it! Grrrrrrrr! Maybe they did put in the M-B coolant, but the core still contained the GREEN stuff from the first radiator service I had in which the upper and lower rad. hoses were replaced. Anyhow, I was advised to change the heater core as soon as possible. He said if the drip continues it will flood the heater core and overflow out onto the interior footwells. I didn't actually see the coolant drip down, but just a small "pool" of GREEN coolant near or on the edge of the tranny pan. The thing is I've never seen any coolant drips/puddles on the ground. I checked all floor areas and they are dry. I was told the heater core is prone to leakage after ten-plus years. Could this GREEN coolant have anything to do with expediating the heater core leak? The quote I was given is--gulp--around $800+, and that's excluding other things they might find that may need changing. I'm a bit disappointed with the shop regarding the GREEN fluid issue.