We blew up the engine in our Cadillac CT5-V Blackwing

  • We took delivery of a long-term Cadillac CT5-V Blackwing in March 2022.
  • After respecting the 1500 mile run-in period, we hit the track for the first performance tests.
  • After about 15 standing takeoff launches, the LT4 V-8 began to seriously skip.

Our excitement at receiving a 2022 Cadillac CT5-V Blackwing for a 40,000-mile long-term test quickly turned to despair after the 668-horsepower supercharged V-8 suffered catastrophic engine failure during our first test session. After respecting the 1500 mile break-in period – keeping the revs below 4000 rpm and not sitting at a steady speed for extended periods – we took to the test track with just over 1800 miles on the odometer to record the first performance figures.

General engines

cadillac ct5v blackwing engine aluminum on valve

General engines

We took the time to play with the Blackwing’s exceptionally customizable launch control feature, which allows the driver to select separate launch speed and slip target settings, then tried some unassisted dances on the pedals with our hamhocks to see if we could beat it (we could). After about 15 launches, we were almost ready to call it when disaster struck. While rolling out to the end of the straight after a run, a large number of warning messages appeared on the gauge cluster, all linked to a serious misfire.

cadillac ct5v blackwing engine damaged block and pistons

The even cylinder bank of the LT4 where all the damage has occurred.

General engines

What happened? That’s a good question, one that wasn’t conclusively answered, even after a complete teardown at GM’s powertrain headquarters in Pontiac, Michigan, where the engine went after it was removed by our local Cadillac dealer. Damage was limited to the even-numbered cylinder bank, with cylinder six bearing the brunt of the carnage; the cylinder walls were notched and aluminum was plucked from the rim of the piston and sprayed on it, as well as on the exhaust valve. The severe temperature and pressure also blew off the ground strap on the end of the spark plug, and even the cast iron cylinder liner showed some pitting.

Bad fuel would have caused this kind of pre-ignition or knocking, but then both banks would have been affected. So Mike Kociba, assistant chief engineer of a small block, thinks it was probably one of two things that happened: either the fuel supply on that side of the rail was somehow exhausted — a contaminant that cut the flow somewhere. limited – or a similar blockage in the cooling system that let things get too hot. But during the disassembly they did not find such a blockage in either system.

cadillac ct5v blackwing engine piston damage

General engines

cadillac ct5 blackwing engine cylinder bore damaged

General engines

Kociba assured us that it had nothing to do with the severity of our use and that the engine can happily launch from standing start all day long. He went on to say that of the roughly 20,000 supercharged LT4 variants of the Gen V small-block V-8 the company has sold to date — in the C7 Corvette Z06, Cadillac CTS-V, Camaro ZL1, and now the CT5-V Blackwing and Escalade V – ours is the first and only failure.

However, this isn’t the first time a Gen V block has been let loose in our hands. The naturally aspirated LT1 V-8 in our 2014 long-term Corvette had to be replaced after a connecting rod bearing failed, likely due to a metal burr coming from the block threads or oil filter.

With our CT5, it took about six weeks for our local dealer to remove the engine, receive a new one from GM and install it. And then of course we had to take it easy again during a second run-in period.

Then we hit the test track again for a lot of hard running, and this time it took a while, sprinting to 60 mph in 3.7 seconds and 11.7 seconds through the quarter mile at 124 mph, shaking off repeated runs. Just as we’d expect from one of the fiercest sports saloons ever.

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