I'd start by verifying the accuracy of the gage. Hook up a scanner so that you can see the ECT signal. At 226, the main fan should be turning on and cooling it down. Compare it to the Display which is from a different source. Shouldn't be much more than a 5 degree difference. If there's a wide difference, you may simply have a sender/display problem - which given the radiator repairs, makes some sense. If the fan isn't coming on at 226, the ECM is probably the culprit. If the ECT doesn't show ambient with the motor cold, simply plug in a 9 buck replacement. If it shows the right temp, replace it. If it doesn't, check wiring and if it's ok, replace the ECM.

If it's getting hot with a/c on, but not off, post it. More than likely a pressure problem and the fan is controlled from yet another source - a switch in the high pressure line. A/c operation should run about 10 degrees cooler - if it's working right - it's exempt from emissions and the stuff in the condensor needs to be maintained at no more than 120 to 140 degrees to make cold air - well below the thermostat or ideal coolant temps.

Most of the head gasket problems are at #7 and occurred well before 50,000 miles. Yours may have been repaired at some time. GM's Bulletin tied the problem to misaligned intake gaskets which led to galvanic corrosion, which eventually eroded the head gasket (and plugged up everything else). Their solution was to counterbore the intake mounting holes for gasket retainers and current production, replacement heads, have this feature. Checking #7 is as simple as pulling the plug. Look for rust on the plug threads.

If you're running both fans check voltage. The secondary can drag it down and if it's on battery or less, the fans will slow down and the temps will climb. System was really designed for the 1 fan which came on plenty of Vettes. The solution is to get it back to the way it left the Factory, and that may simply mean a new battery/alternator.

 

Very interesting SunCr

 

Sorry for the delayed response. I hate when life interferes with fun.

Definitely a valid avenue to pursue for a variety of reasons.
Like I stated before I have only owned this thing since Oct 2007. I bought the least expensive solid Corvette I could find to have a project for my son and I. He is a Iraq vet and is living with me as he goes through the disability system. He has had time to do the bodywork and primer it. Paint and other mods are planned.
I expected to spend $ to get it going but it ran so great I have been driving it every day. I am not disappointed at all I have put 11,000 miles on it so far.
I really don't know the history of the car at all and have done a couple of minor R & R's.
I have been suspect of the ECM's reliability since about the second day but it was just phantom readouts on the info screen that when I verifyed proved false.
She has not ever run poorly; stumbled, coughed, refused to start or left me stranded one time, at 200 miles a day I was impressed. I just have tried not to have a meltdown so when the gauges say trouble I have just pulled over and waited. The highest temp the gauges have ever gotten to is 260 2x, and each time as it hit that mark i shut it down and waited at least 1/2 hour and been able to be on my way. Either way I guess I think I have tried to protect it.
The only coolant put on the ground has been poor aim filling.
She sits now anyway until we figure it out and he polishes things. he did the bodywork and has primed her flat black waiting for my color choice.

Thank you for the thoughtful responses. We are slowly covering the bases.







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