I have a 92 Crown Vic with a 4.6L engine with 135K miles.
But after a trip up north, I noticed that the oil level was still
dropping - not as much as when the valve cover and oil filter mounting
block gaskets were leaking, but still about one quart every 500 miles. I
don't see a leak on the engine - top, side or bottom, so where it is
going? The engine doesn't appear to smell like it is burning oil out of
the exhaust - no blue or black smoke. Do these engines start leaking
internally after a certain time?
=============your first sentence says it all. when the 4.6 gets about 130 to 140k on
them, the valve guide seals give out and fall into the pan. i have
found that it makes no difference if you use synthetic oil or dino oil.
it still happens. i'd have six cars with 4.6 in them. police pursuits,
lincoln town cars, and mustangs, when they hit the number on the clock,
they start using a little oil, and then it slowly creeps up from there.
if you drive on the highway a lot, it won't go through oil that much,
but the city traffic is where you will notice it because it will suck
the oil past the guides from the high manifold vacuum. it will get down
to a quart every 300 in the city over time.
question - ever notice the C.V. taxi cabs with the miles on them. that
puff of smoke on start up from a stop light. that's the tell tale sign.
watch yours after it idles for a while and see if you get the puff of
i've got one right now - a 92 lincoln, with 160k on it and it runs
great, but if you let the engine idle, say with the air conditioner on
this past summer, it will just sit there and puff a little bit and smoke
until he drive off, then it will leave a 10 feet trail and clear up.
they make a tool to replace the valve seals without tearing the engine
hope this helps.
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