04-16-13, 04:44 PM
Anybody else having problems losing/consuming oil? I have an 07' CTS with 85,000 miles and it wouldn't start this morning, turns out it was only because it was 2.5 quarts low on oil. WHAT?! Check engine light never came on or anything and never noticed any spots in the driveway. Took it to a local shop with a GREAT reputation and they said they couldn't find a leak anywhere. Not sure where to go from here.
I have the same year CTS and the 3.6 is known for eating oil. I use Mobil 1 full synthetic and it helps.
01-15-14, 08:23 PM
The problem is that the CTS doesn't have a PCV valve, thus the oil is being sucked into the air intake (due to the power of the engine). If you take off the container that connects to the air intake, you'll find about a cup of oil in there. That oil gets burned through the system. This causes the O2 sensors to fail or worse the Cats to clog.
You need to constantly check your oil level. If it gets too low, it could cause the ignition coil # 6 to fail.
01-15-14, 10:28 PM
2.5 qts low on oil will not keep engine from starting.
01-17-14, 09:53 AM
If you get into the CTS performance forums you'll find wars on whose "oil catch can" is better - one won't stop oil consumption but it will prevent most of it from getting into the cylinders.