Hi all,

I'm new to this board and I've been researching an overheating issue I have with my 92 300E. I haven't been able to find these exact symptoms in the archives so maybe someone can point me in the right direction to solve this problem.

Here are some particulars:
1. I observed a coolant leak on the radiator at the lower connection point below the water pump.
2. I tightened the clamp holding this tube and the leak has stopped.
3. I bled the system at the top of the heads and at the thermostat gooseneck. I also ran the engine with the coolant expansion tank cap removed to allow any air bubble to exit via the coolant expansion tank. I'm more than 90% sure I've successfully bled the system of air.
4. The on dash temperature guage will move up to 120C after a short period of driving.
5. The top hose going from the water pump into the radiator gets hot, (though not so hot that it burns your hand).
6. The bottom hose from the radiator to the water pump is warm near the water pump, but cold at the radiator side.
7. When the temperature guage is at 120C and the engine is turned off, the radiator is hot on the top 1/2 inch. The rest of the radiator is cool to the touch. (This may be caused by heat transmission from the hot coolant hose.)
8. The two electric fans turn on when the temp guage moves above 100C.
9. There is no evidence of oil sludge in the coolant.
10. The radiator and water pump were replaced 3 years ago by the dealer after the top plastic goose neck of the radiator broke. My wife continued to drive the car and ignored the overheating temp guage. This also caused a blown head gasket which was also repaired at the time.

So, if you have read through this long list, what do you think these symptoms point to? Is this a problem with the water pump, (which is where I think the problem lies), or the thermostat, or the radiator. Or perhaps even another component I haven't considered.

Thanks for your insights.

Drew Jenkins