2023 Suburban engine failure 16,900 miles 1 year and 1 week old

Jeff Minnesota · January 7, 2025

My 2023 suburban engine failed with 16,900 miles. The dealership said on the screen by screen analysis of the computer said the coolant temperature was over 300 degrees then engine temperature was almost the same. Would it stand to reason the same cooling system that cools the engine cools the transmission? GM warranty division said to replace the engine but not the transmission. When I try to trade off the suburban the dealership doesn't seem to be interested in wanting to trade. I have tried for 2 months to get help from GM to no avail. Have asked to talk to supervisors and they never call back with any help. Does anyone have any ideas?

Bruin19 · February 10, 2025

Here is the thing. There is a transmission temperature gauge. Did you see the gauge? I always have mine showing along with coolant temp. If you knew there was an overheat you needed to stop driving it. The dealerships argument would be you should have stopped driving it. If you disagree with the decision you should talk to the service manager. Ask him why exactly it will be denied. If still no traction you can take it to arbitration.

Edited February 10, 2025 by Bruin19

asilverblazer · February 10, 2025

On 1/6/2025 at 7:33 PM, Jeff Minnesota said:

My 2023 suburban engine failed with 16,900 miles. The dealership said on the screen by screen analysis of the computer said the coolant temperature was over 300 degrees then engine temperature was almost the same. Would it stand to reason the same cooling system that cools the engine cools the transmission? GM warranty division said to replace the engine but not the transmission. When I try to trade off the suburban the dealership doesn't seem to be interested in wanting to trade. I have tried for 2 months to get help from GM to no avail. Have asked to talk to supervisors and they never call back with any help. Does anyone have any ideas?

Were any transmission temperature codes logged? It may not have overheated the transmission.

What was the failure from the overheat?

What caused the overheat?

JimCost2014 · April 20, 2025

I am impressed the engine would even run up to 300 degrees before it checked out. Nothing as far as obvious signs when it was getting that hot, pretty sure your dash was lighting up like a Christmas tree.

truckguy82 · March 21

So when you boil a pot of water on the stove, it’s 212 degrees. The water cannot possibly exceed that temp. The act of boiling actually cools it down. The more heat you throw at it, it just boils faster, but it does not increase temp.

it is possible to increase the boiling temperature by pressurizing the liquid, but it is not possible to exceed it. (Hence why if you heat up a closed container of liquid and it can’t escape. Instead of boiling, the pressure will just keep increasing and raising the boiling point, until it explodes)

i don’t think it’s actually possible for the coolant temp to reach 300. With say a 15psi cap, and coolant, both of which raise the boiling point, I still don’t think it’s close to 300. Maybe 250-275.

Sounds more like the sensor value maxes at 300 and that’s what they are telling you.

Not sure where the sensor for that is though. I suppose the block could hit 300+ and heat up the sensor without any fluid.

Edited March 21 by truckguy82

davester · March 21

Most likely the o.p.'s sensor was reading 300F because coolant was below the sensor, and the sensor was reading the temp of the air/steam.

And the o.p. seemed to be mixing up engine coolant temps and transmission temps. While the transmission goes through a heat exchange w the transmission, the transmission also has a separate temp sensor, and they would get a separate warning message if trans temp got anywhere near 300F.