I just had a very serious front wheel wobble in my 450slc after a trip to San Antonio. Come to find out that it was a tread seperation on the right front tire. This on a very new set of General tires. I put on the spare and headed home to Corpus. The car acted like it was in a very strong cross wind. I checked the tires and all are radial so it in not that I have one bias ply and 3 radial. Within the last few days I have again developed a very severe wobble in the front end. Today I will check for tred seperation on this tire.
You might check for seperation since your car was sitting over the winter. I can't think that the vibration and the temp. are related. Did you have your radiator cleaned out while your engine was being overhauled? Installed a new thermostat? Checked the fan clutch? Slipping fan belt?