Hi All, first time, I have 1973 240z, with recon L28, was overheating so replaced radiator and viscous fan setup with new 4 core aluminium radiator and new 2x10" electric fans with shroud, no more overheating but when the fans start they send a vibration through the whole car, can feel it in steering wheel when stationery, and the radiator support panel is vibrating, have disconnected both fans independently and vibration reduces but still there, so both fans seem out of balance or ?? Has anybody else had this problem and if yes what is the fix?? Any ideas, crappy cheap fans or ?? Thanks Graham