My little plastic nub just popped off the radiator again. The parts department called it just a fitting, part number 0005000894. It only cost $8.00, so tha is much better than the head gasket. I wonder why it is doing that now. The dealer told me that they do not remove it during the flush or when they were replacing the water pump, but it seems odd that it is doing it now. As many of you have said, it is 11-years-old. I may try just spreading the ends a bit, until I can get back to the dealer. It looks like it is simply held in place by the pressure of the fit. Again, that seems rather odd for such a sophisticated machine, with a radiator cap that is pressure sensitive. Why would they have that second very simple little plastic thing that can just pop off?

 

I have no idea but i have a 20 year old mercedes and it does not do that?...and i flushed the coolant before?

 

change your thermostat. that what my problem was. mine did the same thing.

 

The dealer just replaced the thermostat and it works fine, at least in terms of keeping the car at the proper operating temperature. Do you think I have a defective thermostat that allows the pressure to get too high? Can they pressure test my cooling system to be sure?

 

thats what was happenig to mine, there was too much pressure in the system and that little nub would pop off to save the rest of the cooling system components.