Does a 2003 WIndstar engine have a low oil level sensor?

Early this year I swapped a very low mile 2003 3.8L engine into my 1999. Trying to track down an oil leak from near the top rear of the pan. Have heard the low oil level sensor can leak, but can't seem to locate it.

If there is a oil level sensor, it will be in the oil pan itself. Are you maybe thinking of the oil pressure switch? They can leak pretty bad, since they are under pressure. I'm not excatly sure where they are located on your van, but a parts store may be able to help with that info...

Thanks - I do plan to check the oil pressure sender but thats located above the oil filter in front - leak is in the back. The low oil level sensors are in the pan on the 1999-2000 Windstars. Should be large enough to be hard to miss -

That SORT OF sounds like a rear main seal leak. Pretty common from what I've read (mine included). Does the oil pan have oil all over it but not really dripping onto the ground?

I don't remember seeing an oil level sensor on my '99 3.8l during a rebuild.

The rearward face of the pan is damp with oil up pretty high, about to the mounting flange. The portion of the pan that is stepped up, as it approaches the front main seal region, is dry. It is enough that it seems to be running down onto the exhaust and has a burnt oil smell (faint but enough to be concerned). This reached a peak when I had parked the vane on a steep uphill driveway.

I had set the engine on its pan w/2x4 blocking in order to transport it, move it around the garage, and wrestle with the rear main oil seal r&r (I used the Felpro Teflon, and helped hold the engine up using a crane for this portion). So there is a chance that the weight of the engine compressed the silicone sealant used at the pan/block interface. I have tried slightly over-torque-ing the pan to block bolts and thought the small leak slowed down significantly (will have it back on stands this weekend to look again and swap on new front rotors).

Thank you all for your suggestions.

I don't know if you will have the same experience: I use Felpro gasket sets all the time (in fact, I am using a set just now for an Escort head repair) .... but for some/many reasons, I have never been satisfied with a Felpro rear shaft seal. Yes, I have tried the more costly Teflon ones also. More than once the engine had to be separated from the tranny a second time to again replace the seal ... a lot of work!

The solution for me: Allways buy a Ford OEM replacement rear seal for the crank. Felpro for the rest of the engine is OK ... but the Ford crank seal is thicker/stronger than the Felpro and has never failed me.