It makes us sad that there seems to be a growing problem with some Z06 Corvette owner’s LS7 engines dropping exhaust valves. Classily-named Redditor ImProblyPoopinposted pics of his customer’s car after he heard a pop while “gently cruising down the road.”
Many on Reddit were quick to blame the driver, saying he was lying and he probably over-revved it “gently cruising at 150 MPH,” but this isn’t the first instance we’ve heard of where an LS7 dies at the hands of faulty valves. One theory has to do with the LS7’s valve stem area and it’s ineffectiveness in dispersing heat.
Oil buildup holds onto the heat, galls, and causes the valve to break. But it’s not like the valves are cheap either – Del West is the company that makes them for GM so they are of good quality, so maybe it comes down to a bad batch of valves, which has been known to happen with other parts.
Other theories include valve guide tolerances causing the valve to seat improperly, but whatever is causing it, it’s starting to become more common, or at least more common than it should be. To prevent this failure, many LS experts recommend replacing the sodium-filled exhaust valves found in the LS7 for standard stainless steel valves. But how can one bring themselves to opening up a brand new engine to do major upgrades like that?
Luckily for ImProblyPoopin’s customer, it fell under GM’s powertrain warranty, otherwise a failure like this could cost about $13,000 out of pocket. ImProblyPoopin had this to say, too; “I have seen a failure like this declined once though. A first time customer brought in their CTS to us blown up similar to this. Only problem for them was; the misfire DTC had a freeze frame of 11k RPM, 2nd gear. They somehow missed 4th coming down. They were promptly shut down for coverage.” That’s what we call “the money shift.” Good to know.