Well this was what i was looking for,so far no one has jumped on and said they have seen a bad impeller one one of these.On some cars these do break off,almost all of these are plastic water pumps.
What is throwing me off is there seems to be low coolant flow.Radiator only gets hot near the hose end of the radiator.
220 degrees on the drivers side of the radiator.Over 3/4 of radiator stays at about 100.used temp gun to verify.
Start the car,runs great,idle till normal hot,fans work,new fan clutch,drive car out of drive way and when thermostat opens temp gauge moves very fast to full overheat as only the 220 degree coolant goes into motor.almost like only the drivers side of radiator is circulating.This is verified with a temp gun.
2 new radiators,not behr but this brand works well in all other cars.
Before i put a new german water pump in i will use a 300e radiator i have to verify its not these after market radiators.
For those who use rebuilt water pumps,good luck.
These M104 water pumps are really hard to put in and rebuilts do not always work right.
to answer some other questions,no air in radiator,should have used a Benz radiator but did not.but next time it will be a Behr.Yes bought the car with bad radiator from an elderly lady that had it seviced at benz for every little thing.
Cooling system very clean,old coolant not burnt.
Runs very well but low coolant flow(????)
Will find out next week and follow up so someone else in this boat may find this and read this.
Rich

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88 300E White, sold 9-04
88 190E Black 2.3 sold
90 300CE White, Grey sold 12-24-04
92 400E White,Grey Sold 5-06
90 300CE 91K Signal Red,Black Sold 2007
1989 300CE Smoke silver,Tan Sold 1-08
1993 300E 3.2 M104 motor
1991 300CE White,Grey
1994 E420 beautiful car,gone to new home
1994 E320 Smoke an Parchment.Beautiful car