oil seepage from intake manifold

03 Windstar w/83k. I had the intake manifold gaskets replaced (the lower ones) at 34k a few years ago under warranty. I could see oil seeping down the back of the engine and onto the tranny. I was worried that they might give out, so I took it in to the dealer. I'm still seeing oil (have been even after the fix) that seems to seep out between the intake manifold and the head. Don't know if I should be worried/ concerned. Also, I guess I need to replace my isolator bolts and other relevant parts since I had CEL light on a few weeks ago and the code was bank 1 too lean. What do you think? There has been sometimes before that the engine seemed like it had a vacuum leak, surging at idle, etc. but w/o CEL. (I don't necessarily want to read all 16 pages of the sticky on the first page of the forum). Thanks for any and all input.

ProfKenn

Here is a link to a site that another member put together.
It is excellent....although it shows a 2000 or 2001 windstar......so yours may be slightly different.......for example......your 2003 should have come from the factory with the updated front valve cover.....
http://leckemby.net/windstar/windstar01.html

The genunie OEM lower intake manifold gaskets that the dealership used for the lower intake manifold gasket repair should have been the improved style.....
This means that you should not have to do the lower intake manifold gasket repair again......as they corrected the problems that caused them to fail.....in the new gasket.

It is possible that the oil is leaking out from the upper intake manifold........which replacing the isolator bolts should solve.
I am not sure if FORD corrected the isolator bolt issue by 2003 or not.
It IS normal to find oil in the upper intake manifold....even with the improved front valve cover.
This is because it is NORMAL for oil to come through the PCV line.
The VAPOR that is drawn out of the crankcase can condense....particularly in cooler weather.....and form the oil deposits that you see in the intake.
It is IMPORTANT to draw these vapors out of the crankcase.....as this is removing harmful combustion byproducts that, if not drawn off, would build up in the oil and cause it to break down....and also cause sludge deposits.

One other possble source of leakage, valve cover gaskets?

When I rebuilt my '99 3.8 (... it was not the first time I had dealt with the upper and lower manifold ...) I used new gaskets and seals thru-out, used a torque wrench ...and still had a external oil leak! Then I went thru the upper and lower AGAIN! ... using new seals but reusing the isolator bolts. This last time everything held OK (it seems).

Sometimes unexplainable things just happen!!