Thanks, I will replace the Cap.
I did the fan check as suggested.
With engine hot & running I turned engine off and watched to see how many turn the fan made until coming to a stop.
It stopped after about 15 turns, wow. When the engine is off and cold, it only free wheels about 1/4 turn.
Could the fan clutch be my problem?
Why is the radiator so cold then?
Am I looking at multiproblems? Still confused! Help!
I hate to start replace the rad, fan clutch or water pump without investigating all options.
Oh ya, the cooling system is NOT leaking.
The t-stat is Mercedes and new.
I will check the gage after I find out about the fan spin and cool rad.
THANKS SO MUCH.