I had a 1.9 that had an orange glaze all over the interior of every sq
inch of the engine.  Also,carbon build up in the usual places. A badly
maintained engine. Check the interior of the valve covers to see if you
have a glaze.

I put in "engine medic" from Gunk.Avaliable at Advance Auto Parts,and too
cheap to pass up.  It is for restoring hydraulic lifters. Removes carbon
build up that causes sticking.Why not put some in for the entire engine? I
did this several times. What I got was chucks of carbon flaking off and
plugging  the small oil passseges, and the oil pick up tubescreen.The
symptoms were the oil light coming on at idle.Never came on before.Got
worse and worse. I put this engine to rest.There is no oil pan on the WBX.

Moral to the story-Dont clean a dirty engine. Make sure the engine you
have is correctly maintained.