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2010 Cadillac SRX 2.8T - Click above for high-res image gallery

Apparently, under certain circumstances when gasoline with lower than the required 91 octane rating is pumped into the 2010 Cadillac SRX with the available 2.8-liter, 300 horsepower turbocharged V6, a "mega knock event" can be induced, leading to a complete grenading of the engine. Not good.

The worrisome issue was discovered by Automobiles De Luxe, which happened to be road testing one of Cadillac's latest 'utes. The driver inadvertently pumped in 88 octane fuel, which led to the aforementioned mega knock event and subsequent destruction of the engine. General Motors says it wouldn't have happened if the correct grade of gasoline had been used.

So, open-and-shut case, right? Better use the premium. Not so fast. GM expedited the vehicle to its test center in Warren, Michigan, tore down the engine and came up with a "new calibration" for the engine's computer that will eradicate the possibility of such an event. Six 2010 Cadillac SRX turbos are being field tested in Death Valley to ensure the problem is solved.

The fix will be applied to all new 2010 SRXs and customers will get the revised calibration during regular dealer servicing. Nicely done, Caddy. We hold out hope that this is a sign that the New GM reacts much faster to potential problems than the Old GM.

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    • 1 Second Ago
      • 5 Years Ago
      GM squeezed all it could out of an old design V-6 that was off the corporate shelf. They had to sell that 300hp number to potential Caddy buyers (cheapest engineering solution, advantage Cadillac!). And all GM could come up with is that the car should have had different fuel?
      • 5 Years Ago
      This SRX needs a twin turbo version of the 3.6....then it could make 350hp on low octane.

      BTW what is the deal with people who have $50k+ for a vehicle but try to shim a few shekels by putting lo grade in the tank?
      • 5 Years Ago
      *THIS* is the way to deal with complaints about your company's vehicles.

      I'm sure that GM has learned from that other company's debacle, and would rather come clean than try to sweep this under the rug.
      • 5 Years Ago
      WTF are you guys talking about. GM's always been good about fixing things.

      The ONLY issue I'm aware of is GM using under-engineered rear ends in cars that could be detroyed by aggressive drivers like me. (CTS-V and 4th gen Camaro/Firebrid V8's)
      Other than that, I think GM has been good.

      I'm sure the ricers will claim Toyota's realibility.....
      Oh wait... lol!
        • 5 Years Ago
        Nothing beat a Honda for CHEAP and reliable transportation.
        I've owned many Hondas and I can attest to their reliability.
        Unfortunately, I can attest of their lack of power and torque steer as well.

        On the other hand, many of my performance cars have been GM and they have been VERY reliable. The ONLY problem I had with my daily driven C6 Corvettes and 4th Gen F-bodies were the rear end's on the F-bodies/CTS-V's.
        I think credit shoul be given where it is due.
        • 5 Years Ago
        Yeah bro! You tell em! That's why I see so many GM products from the 80s and 90s with 300k + miles! Oh wait, they're usually hondas, subarus, or toyotas. :
      • 5 Years Ago
      This customer must have been really hitting the gas, because the spark timing is automatically adjusted. Even in the owner manual it says that you can use a lower octane rating in case of emergencies but you cannot drive aggressively or WOT. They are just going to make the car even smarter to make up for the stupid customers.

      Here's what it says in the owners manual:

      If the vehicle has the 2.8L V6 engine (VIN Code 4), use premium unleaded gasoline with a posted octane rating of 91 or higher. For best performance, use premium unleaded gasoline with a posted octane rating of 93. In an emergency, you can use regular unleaded gasoline with an octane rating of 87 or higher. If 87 octane fuel is used, do not perform any aggressive driving maneuvers such as wide open throttle applications. You might also hear audible spark knock during acceleration. Refill the tank with premium fuel as soon as possible to avoid damaging the engine. If heavy knocking is heard when using gasoline rated at 91octane or higher, the engine needs service.
      • 5 Years Ago
      It does sound like a sensor/program issue on the motor, but could have been that WITH an aggressive driver. Good that they delved into the issue instead of leaving it at 'driver error'.
      • 5 Years Ago
      Sucks that it happened, but way to step up to the plate, GM.

      This is how it should you should have been treating your customers for the past few decades.
        • 5 Years Ago
        "...that the New GM reacts much faster to potential problems than the Old GM."

        or Toyota
        • 5 Years Ago
        Which engine are you dumping on now? The 3.0 doesn't have a 300HP rating, the 3.6 and 2.8T do. Are you saying the 2.8T is unresponsive?
        • 5 Years Ago
        @ Oracle99

        I think everyone here agrees that, YES, it should not have happened. But GM is handling the situation admirably.

        Concerning your question - YES, if the car says it NEEDS XX level Octane, then damn right I would expect any one owning it to know that and either use it, or use Octane Booster to get it. This is not the first car in history that has required 91 Octane gas nor is this some extreme requirement.

        I would also venture to guess that maybe in remote areas, cars sold with this engine might already have been reprogrammed for lesser gas from the start... not unlike cars sold in NY or CA sometimes come with different emissions systems right from the factory.

        Don't forget too that the octane rating listed on the gas pump is a MINIMUM rating. If it says 90, it could actually be 91.
        • 5 Years Ago
        Maybe they can start fixing things now that the government owns 60% -- maybe they can fix with our own tax money''''''''''
        • 5 Years Ago
        @ Tool

        I have a hard time believing that an unaltered Porsche can run on ANY gasoline ANYWHERE on Earth.

        I recall reading an article a while back where Ferrari was showcasing one of their new models and driving it from China to Paris (or something like that). They mentioned that Ferrari had to do some computer management of the fuel system (as well as beef up the filtering) to be able to tolerate some rather unpredictable (to say the least) grades of gas in places like China and remote places in the Middle East.
        • 5 Years Ago
        PISS FREAKEN POOR GM!!!!!!!!!!!!!

        This should NEVER have gotten into production with this DEFECT, yes defect!! Testing different grades of gas is a very basic rqmt.... just more junk from GM

        Compare it to Ford's EcoBoost that has been widely PUBLICIZED that it can handle Regular or Premium... who's sweating the details... Ford, not the Giant Mess that continues at Gov't Motors... NOT with my money!
        • 5 Years Ago
        Should've been caught before the product got out the door, but GM is handling it appropriately. Not getting the back-slapping, though--you make a bad part, you fix it.

        Too bad the 3.0 turbo V6 isn't an easier fix. It's really turned out to be a waste of R&D. Much slower and less responsive than the 300 hp rating suggests, and not particularly refined. The 3.6 in the previous SRX was much better.
        • 5 Years Ago
        @John H

        As I asked...
        Do you seriously expect the average middle age lady driving one of these things to add octane booster on every fill up?

        Its not going to happen. Silly to beleive it would.
        • 5 Years Ago
        So what’s your answer to markets that don't offer 91 octane? I live in Anchorage and the "Premium" locally is 90 (which sucks for my little K20z3 but does fine). But I guarantee this Cadillac is/will be sold here. Do you seriously expect the average middle age lady driving one of these things to add octane booster on every fill up? “Just make sure there’s premium in it” wouldn’t work here, knucklehead. In addition, if someone finds themselves in the boondocks with no gas and a station only offering 87, they shouldn't have to worry about risking a blown engine to get home. GM should know better than to not allow for these situations... And they are fixing it. For you to lament the fact that ideal fuel isn’t always used/available is a bit silly, to put it kindly.
        • 5 Years Ago
        This is a pretty basic problem that you would think that GM would have anticipated.

        Even Porsche has figured it out. Every Porsche has been engineered to operate on any grade/quality of gasoline sold anywhere on the planet.
        • 5 Years Ago
        well ahndedl yes, but then this was such a major issue (engine granading) that they had too

        I'd like to see them respond this quickly to small issues - like a door seal letting air in at speeds over 75mph

        I like how they handeled this but I hope they keep this response with small issues
        • 5 Years Ago
        So GM ships a new car with a major software bug that can cause the entire motor to grenade and they get slaps on the back for deciding to fix it? Umm, OK.

        For me, it simply makes me question GMs design and testing procedures. Heck, the car in question only had 2000 miles on it and was basically just cruising down the highway when the whole thing blew up. I love GM as much as the next guy and will agree wholeheartedly that their quality is vastly improved, but stuff like this really makes me wonder what other holes exist in their QC.
        • 5 Years Ago
        Way to step up to the plate? You mean after they said 'using the right grade of gas and this would not have happened' glacially saying it's not their fault the engine can't take non 91 oct fuel or it dies? Sounds like they were pushed into a corner and forced to 'step up to the plate' because of the magazine testing and related publicity.
        • 5 Years Ago
        Defect? Seriously? Greg, you really need to think that through more. GM advertises this engine as 91/93 octane *required* ( http://archives.media.gm.com/us/powertrain/en/product_services/2010/gmna/10truck_us.htm ) So, maybe the people testing the engine should review what REQUIRED means. ( http://dictionary.reference.com/browse/required )

        What's next? Should I be able to pump diesel into the car and have it run too? What if instead of filling the crankcase with 5W30, I use 20W50 - in winter? Or 0W20 in summer? What if I put Honda ATF in the trans instead of the REQUIRED Dexron VI?

        We should expect some basic level of knowledge when operating any vehicle. One would also expect some level of care when driving a vehicle that starts at $50,000. Do automakers really have to engineer the car to compensate for every knuckleheaded idiot out there who thinks gas-key-vroom without the slightest thought to the simplest of things. "Just make sure you put premium in it". Hasn't that been a standard in high-end cars (especially turbo ones) for decades? Half a century or longer? I am totally exhausted with the endless stream of nanny devices and idiot-prevention strategies on cars. It only adds cost and complication to the car by increasing design and development time and ends up making what could be great vehicles into overweight, overprices pieces of mush. I say, stick the magazine with the bill for the engine.
        • 5 Years Ago
        I wonder when Brian Ross, Dr. Gilbert, and Sean Kane will start attacking GM for its unintended obliteration problem.
        • 5 Years Ago
        9:22AM (3/25/2010)I would expect people who spend $50K on a car to treat it right. So, 91 octane isn't available in your area? Maybe one should consider that before purchasing a vehicle that requires it. Somehow

        Derek - you are obviously an idiot, or 12 years old,

        That first sentence is completely wrong, what the hell does price of a car have to do with anything?

        Some people don't treat their $10,000 cars right let alone $80,000 car.

        and what the hell does not putting in octane boost all the time have to do with not treating the car right?

        if you have a $80,000 car, there should be provisions in the car to detect lower grade gas, so it doesn't knock or destroy the engine.

        Or make the car run on lower grade gas.
        • 5 Years Ago
        @oracle: You buy octane enhancer and add a bottle to each full tank.
      • 5 Years Ago
      I thought it was common for mass produced modern engines to auto calibrate for lower octanes to prevent knocking?
        • 5 Years Ago
        I've never put less than 93 octane in my LS2 GTO, but I hear from other goat owners that the car handles the adjustment fine. As a result the vehicle states that premium fuel is "recommended" but not required.
        • 5 Years Ago
        15PM (3/24/2010)
        American auto manufacturers have never been very good at tuning engine computers to do this well...

        actually the Ford Mustang has had this since 2005.

        If you put in higher grade gasoline, then you can get another 5 horsepower out of the 4.6 engine, but the Mustang's engine never knocks under low octane
        • 5 Years Ago
        American auto manufacturers have never been very good at tuning engine computers to do this well...
        • 5 Years Ago
        It can try to compensate with variable ignition timing and other controllable aspects of the engine's running parameters... but it can't outright prevent pre-detonation. Fuel can still pre-detonate.

        For those who don't know the process...

        Low octane doesn't mean high energy content. It means that it ignites easier than the hydrocarbon Octane does. (over 100 octane, ie more than 100%, would harder to ignite)

        gasoline with a low octane number means that it is easier to ignite than that with a higher number.

        Heat and pressure make any combustible substance easier to ignite.

        With direct fuel injection, fuel mist does not absorb radiant heat from cylinder head's intake tract, nor does it wash-down the intake port walls or valve stems. DFI engines have trouble with sooting and carbon coking from oil in the intake system due to EGR, or oil on the valve stems and such, that the lack of gasoline mist in the intake port doesn't wash down and dissolve. It also doesn't absorb heat in that area, on it's way into the combustion chamber, past the valves.

        Add to that heat, the positive pressure of the turbocharger pushing air into the engine... and you have high heat and high pressure. Couple that with easily-igniting low-octane fuel, and detonation can occur at other times than when the spark plug initiates it.

        An explosion at the right time creates the pressure to drive the piston with force. An explosion at the WRONG time breaks parts that are not in an expanding motion cycle.

        Pre-detonation, or "knock" due to it's sound from inside the engine usually happens inside the intake tract of the head, or inside the cylinder as the piston comes up toward top-dead-center, during the compression stroke. an explosion of the fuel mixture while the piston is still rising, forced by the rest of the pistons in the engine, causes a large increase in pressure on all the parts, as pressure multiplies, instead of being used and then evacuated on a power-stroke and exhaust stroke.

        It can break valves, break pistons, blow out cylinder head gaskets, and such. Port fuel injection can do the same thing, and even damage valves from the outside, break or bend stems, blow valve seals, and even damage intake tract parts.

        Any of those broken bits rolling around in an engine creates a cascade of part failures as metal pieces break other parts.

        Direct injection is supposed to help a bit, by narrowing the time frame between when the fuel is injected, compared to when it is ignited... but there is still a lead-time, and low octane fuel still can ignite early, perhaps even before the fuel injector cycle is finished, and the spark plug fires.
        • 5 Years Ago
        I thought so too, but if my mom uses anything less than 89 octane in her Mitsubishi Endeavor, it knocks. I always thought it was just a Mitsubishi thing though.
      • 5 Years Ago
      Good to hear someone that knows what they are talking about.
      • 5 Years Ago
      Why is an auto magazine putting regular into a vehicle with a turbo charged engine?
        • 5 Years Ago
        It just goes to show...

        Just because someone, or a group of people do something that you might think has esteem, doesn't mean they are inherently smarter than your average bear.

        Some are, but it isn't a given. :D

        I wondered how 80% of BMW drivers thought they had a FWD car, too...

        Assuming intelligence is sometimes too far a leap of faith in people, and we have to take a more "benefit of the doubt, but verify" tack.
        • 5 Years Ago
        Because they're morons who don't know what 91 octane *required* means.

        I bet they put 0-wt in their turbo 4's for summer duty, too...
      • 5 Years Ago
      I'm too busy to proofread "reliably". ("get it" lol!)
      So, don't expect me to spell check..... unless I'm being paid to publish.
      • 5 Years Ago
      I really wish the US car driving populous better understood how a turbocharged vehicle works. It's not really rocket science.

      That being said, a simple "de-tuned" fuel and boost map that is employed when a level of knock is reached would've prevented this. Almost every modern, factory turbo vehicle has this feature. It's kinda stupid of GM to have left this tiny piece of programming off of their initial control modules. At least they're mending it without any fight (which serves to illustrate that they are well aware that it's an oversight IMO).
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