Actually
1) The radiator cap was replaced last summer, it did help some.
2) The water pump is an MBZ original, i junked an aftermarket replacement I bought.


maybe this is normal in southern california where it is so hot...although I would still think the car should run cool on the highway even with A/C and temperatures at 100F outside?

I'll probably switch the thermostat out over the weekend for a new one, maybe it is sticking?