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Engine & cooling

2021 Cadillac XT6 Engine problems

Owners have filed 6 complaints about the 2021 Cadillac XT6's engine & cooling with NHTSA - 29% of all its complaints, most recently on October 20, 2026. Stalling, loss of power, oil consumption, overheating, head gaskets, timing chains and engine failure.

Complaints
6
Recalls
0
Crashes
0
Fires
0
Injuries
0
Deaths
0

Engine complaints

Engine & cooling

I noticed a water sloshing sound behind the dash when first starting out for about a month. I didn't get any warning lights or notice anything leaking under the car but when I checked under the hood the coolant reservoir was empty. I made appointment at GM dealership and they found I had a leak along the side seam of my radiator. The car only has 61k miles! I found online that GM has noted a structural design issue in my XT6. The radiators were engineered with tight thermal break tabs. If they stay locked in place...

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they trap immense physical stress during engine heat cycles and force leaks along the seams. This appears to be what happened. If it had occurred while we were on a trip and totally failed while on a highway, I can imagine the result could have been catastrophic. I have contacted GM.

Filed Incident EngineNHTSA 11772504
SteeringEngine & cooling

DTC P0128 engine coolant thermostat to open at a lower temperature than intended. The Check Engine Light appeared, a Steering warning appeared on my information screen, and the engine cooling fan continued to run excessively after turning off. I understand there is a Special Coverage N252508350 for this exact issue, however, GM is refusing to cover the cost of repairs.

Filed Incident Steering · EngineNHTSA 11770960
Engine & cooling

The contact owns a 2021 Cadillac XT6. The contact stated that while sitting inside the vehicle, the vehicle felt unbalanced. Upon inspection, the contact noticed that the H-pipe was leaning more to the right side. The H-pipe was not centered as intended. The vehicle was not taken to the dealer or an independent mechanic. The vehicle was not repaired. The contact stated that in the past, while the vehicle was serviced, no one had noticed that the H-pipe was off-center. The manufacturer was not notified of the failure. The failure mileage was approximately 37,000.

Filed Incident Engine and engine coolingNHTSA 11709237
SteeringEngine & cooling

1)The display on dash reads upon start up, "Steering Assist Reduced". 2)There is no Engine temperature readout displayed on cluster. 3)When the vehicle is turned off, the coolant fan stays running for a few minutes at full speed. All of these issues are correlated. Also, many XT5's & XT6's have had this issue in the past.

Filed Incident Steering · EngineNHTSA 11639372
Electrical systemEngine & coolingFuel system

Car started and ran at idle for 5 minutes. 10 minutes later when attempting to restart, the engine churned for several seconds then ran for about 2 seconds and cut out. "Press to Start" button remained showing green and would not respond to being pressed. The car was stationary in my garage; this would have been extremely dangerous if it happened on the highway. It seems to be a complete failure of the fuel system on a 2021 model with under 27,000 miles

Filed Incident Electrical system · Engine · Fuel / propulsion systemNHTSA 11617101
Engine & coolingFuel system

The vehicle's check engine light came on late afternoon and then started with a delayed turn over, but not actually starting thr following day. The vehicle had to be towed to the dealership. The technician and service advisor commented immediately that it is likely the fuel pump control module. With the commentary about the likely cause was that this is a widespread issue among GM vehicles. Thankfully, the vehicle was at home when it stopped starting but the transition from check engine to stopping operation was almost immediate.

Filed Incident Engine · Fuel / propulsion systemNHTSA 11559826

Cadillac XT6 engine complaints by year

XT6 engine problems, every year

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Source: U.S. National Highway Traffic Safety Administration (NHTSA) complaints and recalls, checked . Complaints are owners' own reports and are not verified. How we use the data

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