98 E 300 over heating

[Nicks1]

Took the car out for a test drive which included 3 runs at full throttle acceleration. After returning to more normal driving speed (about 40 MPH), the temperature gauge slowly rose to 120. For as long as I have had the car (4 years and 150,00 miles) the temp never went above 85, even in the summer with the a/c running.

I changed the thermostat and changed the coolant,but the problem is still there. I'm wondering if the water pump impeller might have failed during the high RPMs (approx 4,500 for 1 or 2 seconds)

Anyone have a similar experience?

Nick

1998 E300
w210 025
150k miles