Unless it has been totally restored, an old MB - even a 560 SL - has very little reslale value - Why? because the mechanics charge $125 per hour, parts are EXTREMELY expensive, and almost every repair is labor-intensive. As my buddy, the owner of a auto recycling yard says: “Those old Mercedes Benz are ‘crushers’ - we crush them into blocks and send them to be melted down and made into Japanese cars!” However, a sometimes accurate source of value can be found at nadaguides.com - just click on “classic” cars - a running vehicle (“daily driver”) is what you are describing - personally, I NEVER buy a vehicle with a broken speedometer/odometer because one can’t verify actual mileage - also, some sellers purposely disable the odometer, just for that reason. Again, as has been stated: a vehicle is worth what someone will pay for it.