25 sounds low , but what are the specs for a 318 stock ? The warning light goes off at 6 -7 psi at idle 10 sounds low , 25 should be okay at 2000 - 3000 , but borderline low , but maybe fine for stock 318 . Best find out what the stock spec pressures are before you start tearing things down. Try another oil , 15-40 ?
How many miles on the motor ?