Chevy's overheating issue is in the past.
When the C7 generation Corvette Z06 arrived for the 2015 model year, it was heralded for its 6.2-liter supercharged LT4 V8, which pumped out 650 horsepower. Unfortunately, keeping that many horses cool turned out to be an issue and many Z06 owners experienced overheating issues at the race track. The owners eventually got together to file a lawsuit against General Motors.
Fast forward to today, and GM now sells an even more powerful version of the Corvette, the ZR1. The ZR1 is powered by a 6.2-liter supercharged LT5 V8, which now pumps out a whopping 755 hp. You may think adding even more power would result in more overheating issues but according to Motor Authority, the ZR1 should be trouble free.
Speaking to Motor Authority, Corvette chief engineer Tadge Juechter said the Z06's cooling issue was resolved for the 2017 model year, so it should only affect 2015 and 2016 models. Juechter pointed out that the issue mostly impacted cars with the eight-speed automatic transmission, so his team changed the calibration and fitted an upgraded cooling system. The eight-speed automatic has closer gear ratios than the seven-speed manual, which causes it to run at higher RPMs on the track and overheat.
Juechter even partially blamed Z06 owners for modifying their cars with brakes, tires, coolant, or cold air intakes. Chevy doesn't test with aftermarket parts, so owners are theoretically opening themselves to issues by modifying their cars. “They’ll do a bunch of stuff that they don’t think of as anything serious and we should validate to whatever mods they’ve done, but we don’t do that,” said Juechter.
Chevy has learned a lesson with the Z06 and will now test its cars to a higher standard. “We learned basically that we had to up our game, and so now we’re validating to 100 degrees,” said Juechter. By comparison, the Z06 was only tested to 30 degrees Celsius (87 degrees Fahrenheit). The ZR1 is now tested using a professional driver who stays on track until an entire tank of fuel has been drained. This is much longer than the average owner will drive their car on the track and should ensure that the ZR1 doesn't experience any cooling issues.
The ZR1 also wears a different front fascia that other Corvettes, allowing the engine to breath better. “The front end is almost all opening. There’s hardly any actual fascia there. So, we crammed it full of as many heat exchangers as we can,” said Juechter. So far, we haven't seen any reports of a ZR1 overheating, so Chevy's efforts appear to be successful.