Thanks Ted,i'll check the tube out of the oil pan.
I got an oil pressure gauge from my mechanic,he told me to check the oil pressure before doing anything else.
What oil pressure should a fresh rebuilded engine have @ idle?

20-25 psi oil pressure at a hot idle would be normal on a fresh engine.

Lorena, Texas (South of Waco)

Made the test with oil gauge and had between 2.5 and 3 bar which is about 40psi with engine cold at idle.  At this point i guess that the engine is healthy and bulb is gone!
Bought a mechanical oil pressure gauge to keep everything under control in the future.
Thanks everybody for your help.