Is it possible that you have a bubble in the system? I've had mine on track multiple times for 30 min sessions and it has never approached overheating. The SC heat exchanger system can be quite lacking but shouldn't overheat the car.
Autocross only and only recently not all all last season
This. ^^^ We autocross with double runs in the summer when it’s 100° ambient and none of us have overheated. I would check flow and for air trapped. The goblin radiator itself holds more volume than the stock cobalt radiator, so with half the weight, it’s more than sufficient. I did upgrade my fan to a Spal (30101522) to pull more air than the “stock” one. That’s all I have done to mine and I don’t think the Houston crew has done anything other than stock.
From your dealer tech days. Your point RE: Balance shaft chain failure is that when that chain fails the water pump is not turning? Correct? Is there an easy GM Tech diagnostic that proves that the Water Pump is not putting out? I mean, I know overheating is a clue, but there are many causes for overheating. No fan, loose coolant cap, cracked rad tank, cracked overflow tank, clogged radiator, etc. I'm just looking for a known diagnostic short cut! I would think you could wait for the car to cool, remove the heater hose that is nearest to the t/stat and spin the motor watching for "powered" flow. IIRC That heater outlet is before the thermostat, correct?
