OnStar Services

See also:

Checking Engine Oil
It is a good idea to check the engine oil level at each fuel fill. In order to get an accurate reading, the vehicle must be on level ground. The engine oil dipstick handle is a yellow loop. See En ...

When to Add Engine Oil
If the oil is below the cross-hatched area at the tip of the dipstick, add 1 L (1 qt) of the recommended oil and then recheck the level. See “Selecting the Right Engine Oil” in this section for ...

V-6 Power
The CTS coupe's standard 3.6-liter V-6 moves this two-door smartly enough, but it doesn't necessarily feel like there's a 304-horsepower engine under the hood. With a curb weight of around 4,000 p ...