my 914 leaks oil badly after a drive-what is most probable source
 

The driver side heat exchanger is covered by oil on the driver's side only. The car had new seals and push rod oil return tubes done recently as well as new main seal. I see oil dripping down from the center lowest point of engine (not surprising since gravity feeds that point.) Are valve covers the main suspect here?The oil leak was there before the main seal was replaced so at first I suspect the main seal was not done correctly but the clutch and flywheel surface were dry (during) before replacement.

Valve covers are common source of leaks, but whenever I do anything or pay to get it done and something is wrong after, that was not before, I look at what I did. GIven this, I would suspect the push rod tubes.

You will need to clean it up, start it and take a look

Do you have the thermostat flaps up on top of the motor? (Major minus points if you answer "no"; if you don't have them the cooling air does not go where it's supposed to go and you'll overheat!!)

Do you have the thermostat itself? (Very minor minus points if "no" on this one. You get extra wear & tear on the motor during the long warmup but no other bad effects.)

How about the pulley that the cable for the thermostat rides on? Did you know that the bolt-hole for the pulley goes through into the sump? It's above the oil level, except of course when you're going around right-hand turns quickly...

This is actually one I didn't learn "the hard way". I learned it through helping a friend clean up the left side of his engine after he figured out his oil leak. :)

Valve covers are almost always suspects as well. It's not that hard to get them "almost on correctly", which results in a pretty decent leak. Make sure that the cover is seated fully on the surface of the head; you may have to pull the wire bail off to check. And sometimes the gasket shifts while you're putting the cover on, most particularly if you wind up moving the cover around while putting it back on. (OK, those I learned the hard way. ;) )

--DD

New thermostat and new wire for the flap actuater. I will clean up and recheck the valve cover gaskets.