I just bought a 1993 300TE with 235,000 miles on it. The car has a new radiator and water pump that were installed before I bought it. I was told that the car never overheated until these parts were installed. The seller was at wit's end and sold me the car at a low price. I suspected an air lock in the cooling system, and after bleeding all the air out, the car does not overheat anymore. It does have the following issues:1) It does not idle at a constant speed, I guess the proper term is 'hunting idle'. It revs up and down all itself. Engine cold or warm it does the same, either way. 2)The electric cooling fans do not come on at anytime unless I unplug the sensor located at the thermostat housing, then they come right on and only shut off if I reconnect the plug. 3) Where the heck did they hide the spark plugs and distributor on this engine? I am used to Fords, Chevys and a Porsche or two, where all that stuff is out in the open. 4) There is a tank on the left side of the engine compartment that says "hydraulic oil" What is is for, and what type of oil do I need? As you guessed, I am new to Mercedes Benz and would appreciate any and all answers to my questions. I think this is an interesting car and I'd like to get some use out of it. Thanks.