[ssgharkness020147]

First of all ditch the thermostats for new ones. They can fail at anytime regardless of mileage. Everyone I have ever heard of that replaced their OEM fan for electrics ran two fans, not one. Call Lynch I know they used to sell a kit, you may want to see if they still have a few laying around. The pushers should help, but not every truck does well with them, in fact some trucks run hotter with the pushers. Fix the temp issue before addressing the surging issue, HUMMER did have a re-flash for the PCM a while back, but your Y2K truck should have had it from the factory.