It cold be a head gasket leak if it shows no leakage outside, i'm sure it's not a cracked block or anything like that. It also depends on how many miles are between when you add oil. If it's a thousand miles don't worry about it. There is a tsb on debris entering due to air cleaner not sealed but it's to late for that on your car due to age. The only other way would be to do a leakdown test on each cylinder see if it's coming out through valve seals or piston rings.
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Tuesday, October 6th, 2015 AT 12:16 PM