Alright, my grandfather gave me his old '91 300E. It has about 180,000 miles on the odometer, service records going back to 1998, and is cosmetically excellent. However, some difficulties have developed with the cooling system. It has been running a little too hot in traffic for a while now; if it sat too long, temp would rise to perhaps 110 C. Temperature remained, and remains, stable while cruising on the highway at 90-100 C. At the time, I was losing a little coolant, but not so much as to be unmanageable.

However, a few days ago, on arriving at my destination at the end of a long, fast run on the highway, I found a frighteningly large puddle of green coolant under the car. Seems that since then, I cannot keep coolant in the system at all; it is leaking a lot. Also, the overheating has gotten worse. Since I had just moved off to school in Austin, I did not have the time to find an independent or attempt to solve the problem myself. I took it to a dealer (Mercedes-Benz of Georgetown). They replaced the radiator, overflow tank, and upper and lower radiator hoses. This has not solved the problem. What else could be the problem? As much as I hoped the dealer would know what they are doing, it seems to me that they just threw parts at the problem, something I can't afford at dealer labor rates.

Additionally, the engine oil pressure at idle on startup is about 1.5 bar, but drops to about 0.3 bar as the engine heats up. As soon as I tip into the throttle, it jumps up to 3 bar and stays there until I am stopped again. The hot idle oil pressure seems kinda low to me. Otherwise, it seems to be running normally; sometimes slightly rough at idle, but no weird noises, and smooth and powerful at all other engine speeds.

Sorry to introduce myself with such a laundry list of issues. I'm just going crazy, and would appreciate any and all advice you guys could provide.