I don’t have to tell you that it’s not good when cylinders explode in an engine.
That’s especially true on a vehicle with just 2,000 miles on the odometer, and especially especially true when it happens to a 2010 model costing over $50,000.
Yet that’s exactly what happened to a Cadillac SRX 2.8T, all because someone ignored the “premium fuel recommended” sticker.
Apparently, the risk of ignoring such advice can result in something GM calls a “major knock event” and an outright explosion of cylinders. Ouch.
Here’s what happened:
An auto reviewer at Automobiles De Luxe was road-testing a 2010 Caddy SRX 2.8T, with the 2.8-liter, 300-hp turbocharged V6, when the engine blew up, leaving him stranded on the 101 outside Ventura, California, at night.
General Motors quickly arranged shipping of the ‘ute back to Michigan and then tore down the engine, looking for the cause of the troubling and dangerous problem.
Seems as though the cause was a simple error by the reviewer. The SRX Turbo requires 91 octane fuel, but was filled with the lower-grade 88 octane stuff.
That apparently set off a chain of events that was described by the article at Automobiles De Luxe like this:
At some point during travel, between 2000-2500 rpm – or normal highway cruising speed – the engine’s management system had adjusted the air fuel mixture to work too lean causing a retarded spark – but crucially – it allowed for a simultaneous turbo boost which led to a catastrophic pressure build up in the cylinder chambers.
GM called it a “major knock event” that probably wouldn’t have happened with the recommended fuel. We all know, though, that high-octane fuel isn’t available everywhere, and engines should be engineered to compensate for lower-octane fuel.
To GM’s major credit, the problem has been diagnosed and a solution was offered almost immediately. GM acknowledged that the SRX’s management system should have been adjusted to accommodate the lower-grade fuel, and a system fix will ensure that it does going forward.
Once finalized, Cadillac will implement the engine management adjustments to the SRX assembly line so that all new SRX Turbos will benefit from the update.
Current SRX Turbo owners will get the revised calibration during regular dealer servicing.
Still, this story is proof enough for me that when an engine asks for 91 octane fuel, it should be taken as more than just a suggestion.
Anyone else think this is a good sign that the new GM’s reaction to solving problems will be much improved over the old GM’s?