i've found that just about all 4.6's start smoking around the 120 to
doesn't make any difference if they have regular oil changes or not. i
think it is probably related to hours of run time on the engine and the
temp. that the valve guide seal soaks in before it cracks and falls off.
the valve tool varies in price but runs around 60 dollars. you can use
compressed air to hold the valves up or use the old standard rope in the
cylinder trick. if you take your time, it will take about 4 hours with
a coffee break or two. the special tool is the key to getting the valve
knocked down to put the seal in.
on the flip side, it usually only smokes when you let it idle at a stop
sign or stop light and that trail of smoke you leave when you take off.
normally, at 60mph, you don't use hardly any oil because of a
lower manifold vacuum.
got three of those towncars with that mileage on them and had to replace
seals on all of them. that seems to be the only major weak spot on the
maintenance with them.
hope this helps.
knowledge is power - growing old is mandatory - growing wise is optional
"Many more men die with prostate cancer than of it. Growing old is
invariably fatal. Prostate cancer is only sometimes so."