Stuck Thermostat. Vehicle not achieving operating temperature in the correct time. ALL 3 of the people I know with CT-6's had the exact same issue this year.
Engine & cooling
2018 Cadillac CT6 Engine problems
Owners have filed 4 complaints about the 2018 Cadillac CT6's engine & cooling with NHTSA - 33% of all its complaints, most recently on June 23, 2026. Stalling, loss of power, oil consumption, overheating, head gaskets, timing chains and engine failure.
- Complaints
- 4
- Recalls
- 0
- Crashes
- 0
- Fires
- 0
- Injuries
- 0
- Deaths
- 0
Engine complaints
The brake makes a rattling and metal grinding sound, the dealership said nothing is wrong with the brakes, still problematic. The transmission shifts too hard. Dealer said nothing wrong. Yet cat kicks too hard.
My cadillac ct6 (2018) quit working while on the expressway. I was in the middle of no where, in georgia. This made for a very dangerous situation as the car suddenly lost all power going to the wheels while driving at approx. 75 Mph. I was barely able to get around traffic to be able to pull over as there was 0 power. When the tow truck from cadillac arrived we were told we were not allowed to ride in the truck because of covid. We were made sit in the rain in 40 degree weather while I spoke with my home cadillac...
Read the full complaint
dealer as well as the nearest to where I was. Both dealers were extremely unhelpful, my car is still under factory warranty and was just in for transmission work about a week prior (i've taken the car in three times for transmission issues and it still has something wrong with it. I was told by both cadillac dealers that they would not help because they needed to 'diagnose' the car and couldn't until five days later. I was offered an uber ride in a city that had 0 zero uber, taxi or lift services. I was hung up on by these people, they were rude and this was on christmas eve. I had to walk to a car rental company and pay over $400 dollars so I could spend christmas with my family.
My engine light is on and this is the 15th time I have bought my car in for various engine problems like engine power reduced and other problems with this car. The car would just stop in the middle of the ride or jerking as I drive it. I have been on the highway when it has stalled before as I drive. I have had these problems since I purchased the car in 2018
Cadillac CT6 engine complaints by year
CT6 engine problems, every yearSource: 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