I'll be curious. Aside from crud at the lower back of the 6th cylinder (which might or might not be the case here) "stuff" blocking the tubes in the radiator is what I'd say might be the next in line of problems. If you disturb things those can get clogged and that'll be a problem. Thermostats? I've had two fail. The new you you have wasn't sold under the name "Fail Safe," was it?
