[A/S] 370LE (Ford 460) engine overheating

["jtc22903"]

My 1989 370LE has been in and out of the shop all summer with a still-
unsolved problem with engine overheating. The engine is a Ford 460 
with 14,000 original miles. No prior modifications to any 
engine/drive component. Everything worked well prior to this 
problem. The shop has done all of the obvious repairs and checks 
(radiator cleaning, check/replace belts and hoses, replace sender and 
dash gauge and validate readings with heat gun, check water pump, 
timing, fan alignment, replace fan clutch, etc.), but nothing seems 
to solve the problem. The engine itself has passed all of the usual 
checks, including chemical analysis of the oil, compression checks, 
without any problems. This problem is new this year, and it came 
suddenly. The shop is now looking for an auxiliary fan system to 
supplement the factory system. Has anyone seen/solved a problem of 
this kind? I will appreciate any information. Thanks. John