2021 Denali died while on the road - 292 total miles

[MLRTYME]

Its did the same to me. Its your valve springs. My number 6 broke. Its a defect from the manufacturer. They had to replace all of them. There's a TSB out there. Its a one to two day fix. Hopefully compression holds and if not, new engine time. Keep us posted.

"When valve meets piston" isn't a story I like to hear. I would be very wary of a simple compression test determining health of the engine initially... knowing the long term damage that most likely will occur in the valve guide even if the head of the valve does manage to stay in tact.

After my stint in NHRA, I guess I think in terms of a broken valve spring or retainer/lock when pushing an engine past 7000. At those piston speeds, you don't get a chance to salvage any portion of a dropped valve. Maybe 1200-1500 rpm is different as I've never dropped a valve at such a low rpm, so I honestly wouldn't know. But in my experience, a dropped valve usually means a complete rebuild with a new piston and head work.

 

[Dexmon]

I'm very sorry to hear that sir. I have a 2015 Suburban LTZ and I've had nothing but problems with that truck. As much as I like the new GM trucks I'm not touching them now. I'll wait two years or so before I buy one. Hopefully by then they'll work out the bugs in them.

 

[Suwanee 07 Tahoe]

Reminds me of my Body Control Module issues a few years back. Driving down the highway and everything shutoff and on for a couple of seconds... As if possessed. Replaced the BCM (seven years ago) and have had it re-flashed one time since (six years ago). Only 149K miles. Great ride. I'll never be without a Tahoe!
Wish you all the best and look forward to the "FIX". Looking at the 2021 Tahoe or holding out till 2022.


07' Tahoe LT 5.3L 2WD, Only little tweaks: K&N Intake Filter and Tube, Jet MAF and JET Throttle Body. (Jet MAF made all the difference.) Factory MAF Show with the restrictive "web" or "honey comb". Jet was wide open with just the elements dangling in the wind...

 

[Early]

Terrible news on your brand new Denali. From what I've read and experienced myself, you're probably going to end up loving that truck. My '18 has about 40K on it now and has been a great ride. Average gas mileage since new is 20 mpg, original tires still ride like glass, 4 wd works great, etc. Hope it's a simple fix.

 

[KitchenMaven]

Hi, I bought the fully loaded options 2021 Denali end of July as it came off of the transporter. So far, no issues and I have almost 7,000 miles on it. I drive over a curvy mountain to and from work. I still have my 2003 Denali also and have over 250,000 miles on it. Still runs fine. May need a new transmission coming up. A couple of my favorite features are now gone: can’t move the gas pedal toward me so now I have to move the seat closer which I don’t like; they got rid of the dual visors and left a gap for the sun to get in to the far left of the visor, so as I’m driving over the hill to work, the blaring sun gets me on alternating curves. Also, you can only use your right hand to pull the visor out because the well to pull it out of its recessed spot is on the right; gas mileage -need a gas tanker behind you... The other thing I miss is hands-free calling through Onstar. I haven’t mastered the car play and voice controls but it seems I have to take my eyes off the road to do so many things related to the phone. I try to get everything set up before I set off for work but sometimes I still need to adjust. The thing I am most upset about is the lack of a 2nd visor, which I used all of the time in my 2003. I didn’t buy the car for the luxury aspect, Although amazing, but I tow my trailer and wanted a new reliable transmission and newer features with the times. Other than those things, the car is a dream to drive and has so much space! Seats are so easy to fold down with the push of a button. Love the larger roof slider. I feel safe for sure.

 

[PG01]

"When valve meets piston" isn't a story I like to hear. I would be very wary of a simple compression test determining health of the engine initially... knowing the long term damage that most likely will occur in the valve guide even if the head of the valve does manage to stay in tact.

After my stint in NHRA, I guess I think in terms of a broken valve spring or retainer/lock when pushing an engine past 7000. At those piston speeds, you don't get a chance to salvage any portion of a dropped valve. Maybe 1200-1500 rpm is different as I've never dropped a valve at such a low rpm, so I honestly wouldn't know. But in my experience, a dropped valve usually means a complete rebuild with a new piston and head work.

Most here have no idea what you mean....

 

[gonatee]

My gm service manager/friend told me to stay away from new gms for now. Too many problems, no parts, no customer service.
Shame on gm.

 

[gonatee]

Hi, I bought the fully loaded options 2021 Denali end of July as it came off of the transporter. So far, no issues and I have almost 7,000 miles on it. I drive over a curvy mountain to and from work. I still have my 2003 Denali also and have over 250,000 miles on it. Still runs fine. May need a new transmission coming up. A couple of my favorite features are now gone: can’t move the gas pedal toward me so now I have to move the seat closer which I don’t like; they got rid of the dual visors and left a gap for the sun to get in to the far left of the visor, so as I’m driving over the hill to work, the blaring sun gets me on alternating curves. Also, you can only use your right hand to pull the visor out because the well to pull it out of its recessed spot is on the right; gas mileage -need a gas tanker behind you... The other thing I miss is hands-free calling through Onstar. I haven’t mastered the car play and voice controls but it seems I have to take my eyes off the road to do so many things related to the phone. I try to get everything set up before I set off for work but sometimes I still need to adjust. The thing I am most upset about is the lack of a 2nd visor, which I used all of the time in my 2003. I didn’t buy the car for the luxury aspect, Although amazing, but I tow my trailer and wanted a new reliable transmission and newer features with the times. Other than those things, the car is a dream to drive and has so much space! Seats are so easy to fold down with the push of a button. Love the larger roof slider. I feel safe for sure.

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So they got rid of adjustable pedals on the 2021 ? Is it an option now, or just gone?

 

[Duke40]

2021 Denali with 2000 kms. Started getting gas smell when stopped at lights or any time idling. Took to dealer he said any smell was normal and they found no fuel leaks.
Since the weather has turned cold it cranks for 5-7 seconds plus to start plus fuel smell is getting more pronounced. Took it back today and at least they now agree it smells like fuel. Not sure what the diagnosis is going to be. A new vehicle with issues sucks. Kinda like being nagged when still on honeymoon....just shouldn't happen.

 

[B520044]

I have over 7500miles on my 21 Yukon. My advice is to stay far away from them. Its currently at dealer service for the 4th time and I sit here at the end of the day wondering if I can pick it up or not; never get a call when it's done. Always calling them to check on status.... Customer service at GM sucks.

Scotty Kilmer is right! Stay far away from modern day GM products.