Leaking coolant from a cracked intake manifold gasket is an extremely common problem on most GM vehicles made from the late 90s to the mid-2000s. Most experts agree that the problem stems from GM's 'DexCool' coolant which erodes away at the intake manifold gasket
There are over 225 complaints on CarComplaints.com related to excessive oil consumption from Chevrolet engines. Many owners of Suburbans, Avalanches, Prizms, Silverados, Tahoes and Aveos are claiming they need a new quart of oil every 1000-1500 miles without any visible leaks. In addition owners are claiming their vehicles feel like they’re driving through mud, or being bogged down.
What Causes Chevrolet’s Oil Problem?
All engines require oil to lubricate and protect the moving parts of an engine from wear. These parts include cylinder walls, pistons and piston rings. When a piston moves down its cylinder, it leaves a thin film of oil on the cylinder wall. This tiny amount of oil partially gets consumed by the combustion process and therefore it’s normal to see a small amount of oil reduction is the engine.
What’s not normal, however, is to see the rapid and extreme oil consumption of some Chevrolet engines.
According to a Chevrolet service bulletin, the most common cause is stuck oil control rings. Generally the stuck oil control rings are the result of excessive oil on the cylinder walls and this excessive oil can come from the PCV system and/or the AFM pressure relief valve in the oil pan.
Upon inspection of an engine experiencing this problem, you will typically see an oil-fouled spark plug. Although excessive oil may also show up in the intake manifold.