Check oil level, electronics on used STS
Attempt to invest in a model sold by a dealership familiar with the vehicle, and seek out a unit with full service records available. In particular, be sure the model was treated to regular, high-quality oil changes. Some issues, though somewhat inconclusive, were noted with oil consumption and (possibly related) timing chain failure which is expensive to repair and may result in catastrophic engine damage. A lower mileage engine that’s had religious oil changes is your safest bet.
Check the trunk thoroughly for signs of moisture. If dampness, a mildew smell or rust is present, it could be caused by a gasket leak around the centre brake light that allows rain water to enter the trunk.
Have a mechanic inspect the STS for signs of leakage from the engine, transmission and differential. Also, avoid any model that exhibits a ‘shudder’ through the driveline at lower speeds and RPMs. This could be a sign of a bad torque converter, which is expensive to repair.
Note that issues regarding oil consumption and cooling system glitches on older Northstar V8 engines seem to have been rectified for this generation of STS – though shoppers should still have the water pump checked for signs of leakage.
The Verdict: As with many luxury cars, the driving experience, comfort and looks of the STS are its largest draws as a used buy. Careful shopping and a thumbs-up from a Cadillac-trained mechanic should be considered mandatory ahead of your purchase. Though reliability looks reasonable, higher-than-average repair costs mean the used STS is also a good candidate for any extended warranty coverage available.
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2011 Cadillac STS RWD Specifications
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