hi i'm bill
first how many miles in that 3 months? if it was 3000 (average) you are ok that equals less than 1 quart in 1000 miles which is perfectly ok for any car or truck you have a problem when you use MORE than 1 quart in 500 miles. if you are a heavy driver and put say 6000 miles in 3 months your oil useage just jumped to 1 quart in about 2000 miles which is great.
the spec for oil usage in a new engine (under 50,000 miles) is 1 quart in 1000 miles or better, any engine over 50,000 it drops to 1 quart in 500 miles.
now with that said, if you are in the range of needing to have something done, any oil leak will cause you to lose oil and you may not see anything at all on the driveway you need to look under the car anw wet spots are oil coming fron somewhere a dye added to the oil will pinpoint it. ok the engine is dry then you need to go in the engine looking for worn valve seals worn oil control piston rings or a bad valve guide, all of which are very uncommon UNLESS you are NOT changing the oil according to the MINIMUM (5000 miles between oil changes) spec set in the owners manual the prefered interval is3 months or 3000 miles between oil changes WHICH EVER COMES FIRST
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