N14 engine. My car uses alot of oil and blows out smoke when accelerating hard, theres also some suction when I remove the oil cap when the engine is running. The car has 114k miles and has had one valve cover replacement as far as I know. The valve cover has about 35k miles

 

The suction is normal, don't remove the cap/dipstick while the engine is running as it will stumble and its designed to run under a vacuum and throw codes. Its kind of hard to tell, you can get oil from bad valve stem seals also which create the blue smoke at take off. Most people just change the valve cover and then check if the blue smoke disappears, if it does not then its the valve stem seals. On the N14 engine the valve is integrated into the top and not a quick change like N12/N16 or N18

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