Questions and Answers

Chevy Motor Has Zero Oil Pressure Q. I Have a 1987 305 Chevy Motor In a 1977 Chevy truck. When cold it holds about 30 to 35 psi on the oil. After it warms up it drops to almost nothing. I dropped the mains and the rod bearings and they do not look bad, just a little scratched on the mains along with the crank which can be cleaned up with some emery cloth.

Also the lifters where not oiling very good either. The pump screen is very clean. Could this low oil pressure be from just a worn out pump? I plan on putting in new bearings and a high pressure oil pump. Hope this helps?

Thanks,
Paul

A. I would suspect the pump first but I do not know the maintenance history of this engine, do you? The other place to look at is the cam bearings. I have seen one "walk" out of it's bore and just dangle on the cam. This would give you a oil light at idle with usually no knock noise.

You could blow air into the main oil gallery to see if there is a massive leak somewhere. You only get one shot at this as once you blow all the oil out of the bearings it will sound as if all the bearings are bad. Check the pump and it's pressure regulator first.