I've been having an oil leak for some time and getting extreme. I thought it may be the rear main seal, but after doing some reading one here, starting to think it may be the oil pressure switch. My oil light has been coming on when I start my car and usually goes away after I give it some gas. I was thinking maybe my light was coming on due to the oil leak coming from my switch or sensor, whichever may be the proper term. I've tried to track down the leak without much luck. Could an oil leak at the sensor cause it not to have enough pressure on it to work properly until a boost from the engine. I went to put in some oil earlier and it looked pretty bad as far as the leak goes and the light did not go off for a little longer than usual. Any thoughts or help would be great.

 

You should be able to take a look at the oil pressure sending unit and tell if it is leaking from there or not. I don't really know where it is located on an 86 305 engine block, but I would start by looking around the oil filter.
The short answer is yes, a busted oil pressure switch will cause your oil pressure light to come on. However, if the leak is not severe enough, I would expect for the light to come on after the motor has warmed up and is at idle. The higher oil viscosity of the cold oil will minimize the leak and also produce higher oil pressure until the engine warms up.
But I have never heard of an oil pressure sending unit leaking so much. Check to make sure that you don't have a loose oil filter or something like that. You can also remove the oil pressure switch and hook up a mechanical gauge to make sure what the actual oil pressure is.
Non the less, oil starvation is never a good thing if you have been running the car low on oil. How many miles are on the engine? Worn main bearings can cause a low oil pressure condition as well.

 

the oil not leakin until warm is understandable. the light coming on at first starting the car i don't know about. it will stay on for a good while if i start the car and let it idle. the leak has been going on for a long time, just hasnt been severe until recently. its almost 170k miles, a suppposed overhaul has been done. i dont know the extent of the overhaul done although. i guess a little more diggin into the leak will have to be done. if anyone else has any ideas, feel free to comment. any ideas are better than havin to take it to a shop if i can get away with fixin it myself.

 

found the oil leak. i know it's been awhile since i put this up. it was coming from oil pressure sensor, or what i believe may be what its called. it was almost right under the distributor. you could blow right through it. replaced it and solved everything. just in case anyone else might have similar problem.