I have a 91 Isuzu pickup with a 2.6 carb setup. And I just got it running but now the oil pressure light keeps coming on. I seen the oil sending unit has a small leaking drip to it and I was thinking that could be it but I want to be sure. Oh yeah I'm using5W-30 Valvoline.

 

When does the light come on? If it only comes on at idle, and especially if it is worse when hot, the most likely cause is worn main bearings. You don't say how many miles on it. I'd recommend unscrewing the oil pressure switch & screwing a mechanical test gauge in to see if you really have an oil pressure problem or just a light that lies to you. If you truly have an oil pressure problem, and if it turns out to be main bearings, the engine will need to come out. Edited by: Craig