[Shotimes] Overheat - Part II

[Steve Tatro]

Thanks to everyone who responded with advice.  I had the system pressure tested, everything there was fine.  I also had a pressure test done on the block, at least that's what they told me, and there's apparently no head gasket problem.  Sort of what I expected since it seems HG failures are so rare on the SHO.  For the heck of it I paid them the exhorbitant amount they demanded to do a chemical flush/refill of my coolant system.

On the way home, same thing.  Temperature goes waaay up to the "N" in NORMAL, even a bit past a couple of times.  This was on the highway going anywhere from 65 to 80 mph.  It seemed to help a *bit* if I made sure to get in some clean air instead of "drafting" the car in front of me, but not much.  What did help (and kept me from overheating) was switching the EATC to FLOOR and turning the heat all the way up.

Does any of this help anyone make a long-distance guess as to the problem?  Theoretically the car shouldn't even need a cooling fan at that speed, right?  So I should be able to cross that off the list.  Besides, even putting the EATC in full AUTO didn't help, even though it forces the fan on (AFAIK).

I guess there are three things I can think of: thermostat, radiator, water pump.  Thermostat replaced a couple of years ago, radiator about 5 years old (but always with plenty of fresh green coolant), water pump about 2 years old (went bye-bye suddenly one day).

Ideas?  I appreciate it.

Steve Tatro
Red/Black '93 with 178k miles
Monroe, Ohio