Ford Repair: 99 for expedtion 4.6 and oil sludge, valve stem seals, piston slap

Question
Hi Mark, I have a 99 expedition 4.6 and I just turned the big 200,000 miles.  I've recently noticed a sludge buildup in the oil filler of the engine right at the cap, and it's burning more oil than ever before.    Probably about 1 quart every 1000 miles or so.  I use synthetic oil and have no problems to speak of, other that a little piston slap on the cold mornings.  It runs fine and it doesn't appear to leak oil.  any ideas as to the cause of the sludge?   Thanks

Answer
you could possibly have bad valve stem seals causing oil usage-a clogged pcv valve could also-worn or sticking rings-

as far as oil sludge if you are changing at correct intervals and using a good quality synthetic oil you shouldn't be getting any sludge from that. i've never seen a sludged 4.6 that wasn't caused by poor maintenance at some point-they have really big oil drains in the heads you might try using a pint of marvel mystery oil about 50 miles before next oil change and try this a couple of times.

make sure your oil isn't contaminated with water-