2023 1SS @23k mi. - dealer reports blown head gasket
 

Left the house, coasted through my neighborhood and was sitting in traffic when the engine started shuddering, so I pulled over and it died. Started it and it ran awful so I turned it off. I used OnStar for roadside assistance and they sent a flatbed to transport to my dealer. Tow cost me nothing.

I showed the tow truck driver the tow hook, and we used it to get the car on the trailer. Had just enough clearance. The driver took photos and said this was his dream car. He took good care to secure it.

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Dealer said they found coolant in cylinders and claim it's a blown head gasket. Obviously, we are all aware of collapsed lifters. I didn't hear the classic lifter tick, it just ran awful. So we will learn more once they pull the heads. I asked them to give me a call when they do so I can come take a look at any damage.

Additionally, I informed the dealer that I had filled my fuel tank less than 1/4 mile before the engine ran awful. Then a few days later that gas station had all of those pumps taped off. I went in and they admitted they have an issue with their premium tanks (Top Tier Phillips 66). I gave them my contact info and asked they let me know what they find, but I expect I need to follow up. This wouldn't explain coolant in cylinders, but we'll see what happens.

My dealer has been great. They have parts ordered and expect to tear into it next week. They gave me a 2024 Trax Activ as a loaner. Obviously, I'll report back with the results.

Given my driving habits, this car has spent A LOT of time in V4 mode. My 50 mile MPG best is 38.4. I did the break-in properly, and keep up with oil changes using the correct 0W-40. I've paid a lot of attention to the AFM system, and I expected to add a range module after the warranty was up. We'll see if AFM had anything to do with this, there was a switch to/from V4 when it ran rough.

Unbelievable. Sorry this happened to you. I have read your prior posts and I know you're a thorough guy who knows what's going on with your car. Because of that, I trust this failure wasn't due to something you did wrong. Hearing about random failures like these, is why it took me so long to buy one of these cars. Just sayin! Please keep us informed, thanks for posting and hopefully it's a quick fix for you.

I’d be inclined to believe it was bad gas ( water instead of coolant ). I had a new GTI that did the same exact thing as your car, 1/4 mile after getting gas. More than 50% of my tank ended up being filled with water.

Anything’s possible though, maybe it’s just a coincidence that the pumps were shut off and it’s a head gasket issue? I just haven’t seen anyone say that they’ve had that problem here (at least that I remember)

Good luck.. at least you had the tow hook port. That’s the one thing I wish I had access to…

Thanks! I have paid close attention to the car, so I know it wasn't abuse or neglect. While I am surprised, I'm not mad. I'm lucky enough to have other vehicles to drive and the loaner means I'm unaffected, technically. While I drove my Camaro daily, it was by choice.

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I'd be shocked if bad gas didn't play a role and I'm certainly keeping that investigation in mind. I don't expect the gas station to willingly give up that info, so I'll have to be persistent.

The things I would do to have that garage setup lol..

The detached garage (with a full second level) was the primary selling point for the home (purchased in 2020). My wife and i agreed that whatever we bought had to have an out building for cars/projects. The attached garage is conditioned, has a floor drain, and has a dumbwaiter for taking groceries/stuff up to the kitchen above. It's pretty dope.

My big plan is to empty that barn and lift it, increasing the height by at least two feet, then add side posts and steel beams to eliminate the center posts. That would allow for one larger door. There are two posts that run along the middle and support the LVL, and it's annoying having to work around them. Also, the 7' doors really limit what I can park in there. At that time, it would get insulation and a furnace. Probably a $30k investment.

Update - Dealer has parts in and has pulled the car into the shop to start tear-down. I'll drop by this afternoon to view progress. I want to see what the head and block look like and what the failure mode of the head gasket was.

So doesn't sound fuel related then?

UPDATE -

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Spoke with service and mechanics. The guy I talked to builds race cars and engines for fun, let alone as a career. We discussed the head gasket failure. There are a few small spots on the head gasket where coolant got thru (I didn't take pics of them for some reason). The spots were really small and minor, but the engine only spent 30 seconds running with the compromise.

They checked level on the heads and it's within .002 on the width, and the length is perfect. The block is perfect.

They told me about a new process for dealing with build-up on the intake valves. They have a process that does clean the valves, but GM recommends it after every third oil change, and it's not cheap. The system controls engine RPM, it takes 45 minutes, and it washes chemicals across the intake valves. An oil change is needed afterwards. So, it's GM acknowledging the issue with DI engines and intake build-up, but every 15k-20k needing a $300+ service is unfortunate. The mechanic said they've seen huge improvements in idle and performance in vehicles with as low as 30k miles.

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Intake at 23k miles
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Wow that intake looks caked. Did you have an oil catch can?

Right? While mine is parked under cover it definitely deserves at least a garage in general.

Luckily, that place undercover is the future garage once it gets closed up/insulated and all that. Next winter she'll be nice and cozy.


Thanks for the info on the carbon buildup. That was one of my worries of purchasing a new car was the DI. I like the power/responsiveness it entails, but it's just another thing I gotta keep up.
Not sure I like the idea of running chemicals through the engine to do so, though I'm sure it can't be that bad if they're doing it.. Interesting idea

No catch can, left it stock to prevent any warranty issues.

I also use the AC Delco fuel treatment at every oil change.

uh, spark plugs are on the outside of the head....

What are the darkened ports on the 3rd and 4th pic?