Hello  atf,

This oil leak location is vexing me.  I have a '96 F-150 I-6.  On
parking the vechicle I get about 100 drips of engine oil.  Last
September I changed out the oil pan gasket.  Right now I can't localize
the location of the oil leak.

Only the left side (looking foward) of the block has oil coating.
Nothing is leaking out of the tailpipe.  The inside of the exhaust pipe
is pristine.  And I do not see any oil coating or leaking on the right
side of the block.  The oil drips down off the saddle shaped cross
member that spans between the motor mounts and is ahead of the deep
draw portion of the oil pan sump.  The pan is rusty, and I could
believe a hole in the pan would provide a leak.  Furthermore, the
gasket is damp with oil and this is the case *after* I changed out the
old, cracked oil pan gasket, which I thought was the source of the oil
leakage.

I could guess that the oil leak is from the front and rear main seals.
But this engine has 90K miles.  The oil leak started rather suddenly; I
noticed it this past July and it has stayed the same or gotton a bit
worse.  As I have mentioned, I changed out the oil pan gasket this past
September.  However, I can't believe my guess that the main crank seal
is leaking because I have oil dampness on the entire left side of the
block, front to back and up to the elevation of the head gasket but not
above the head gasket.  The motor mount on the left side shows dampness
from the oil.  One more thing, a bit over a year ago I changed out the
oil plug and  o-ring gasket as that was a source of some leakage, and
things were fine from that point until this past June-July.

Right now my oil consumption from the leak is about a quart on every
third gas fill up.  Before this leak started I had about 1/2 quart to
add every 3 thousand miles, ie every oil change.

One more thing.  The side of the engine block that has complete oil
dampness has a long rectangular cover that is attatched to the engine
block.  What is under this cover?  Push-rods?  I could guess that this
is the problem, but the dampness from the oil is both above, ahead,
below, and aft of this narrow-long rectangular cover.

Given how quickly the oil drops off and pools under the engine after
parking,  100 drips/15 minutes then it stops dripping, this suggests to
me that I have a leak from the pressure side of the oil system.  I
could guess the oil pressure sender, but the dampness is extensive in
area.  The oil pan gasket is not on the pressure side of the oil
system; or am I wrong?  What about a plugged PCV?  I don't know where
the PCV is located, on top of the valve cover?  Again, I don't have any
oil dampness from the head gasket on up topside.

Finally, a loose oil filter.  No.  It is tight.  And I change the
filter every 3000 miles on the oil change.  And the oil dampness is
above and in front of the oil filter, but the dampness is on the same
side of the engine block as the filter.  And the other side of the
engine block shows no oil dampness.

Boy, I purchased this 1996 F-150 with 40K miles four plus years ago
thinking I was getting something sturdy and a good runner.  (Very soon
the clutch slave cyl. had to be changed out!  Arrgh!)  And now this oil
leakage problem.   But it is not piston blow by.  No blue smoke.  No
sooty exhaust pipe.  

Thanks for any suggestions.

Rob Mohr