1999 mercury grand marquis LS has 120,000 miles and is using oild
have your mechanic tighten those gaskets~ the leak will stop~
If your leaking a quart every 250 miles you would notice it on the ground. It would be everywhere thats alot.
could be a loose oil filter, two oil filter gaskets by mistake or a leaking drain plug because they forgot the little copper washer~
My guess with the word "uses" is that it burns oil. Looking at the vintage, I suppose it has a bazillion miles on it and has worn out valve seals, guides and rings. (Bazillion is, of course, a technical term)
At 120k or actualy at 100k the engine should of been taken to a dealership or trusted mechanic an had a routine tune up. If its not being found under the engine. Have the mechanic you trust check for oil sludge along the base of the engine where the manifolds meet the block if nothing there have them also check the upper block near the PCV inlet. Also if have gone from standerd 5w30 to the synthetic you may notice a usage increase as the cars engine if not completely cleaned out of all the old oil an sludge will tend to fight the newer oil. 92 thru 99 are also known for gasket leaks that while not substantial over a day to day period will after around 250 miles or 2 full tanks use eat around a quart of oil.
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