1987 307 Oldsmobile Engine VIN-9. I found some oil leaks on my new purchase, so I checked the bolts and all were loose. I have a Haynes manual that says the torque on the oil pan bolts are 15 ft./lb. But, the bolts seem too small for so much torque. My engine has 13mm bolts on the front and rear corners of the pan and 10mm bolts for the rest. I didn't want to over tighten the bolts, so I just snugged them with a 1/4 ratchet. Can anyone verify the correct torque for me with a GM Service manual? Also, the engine had no leaks when purchased. Could excessive oil pressure have caused the bolts to loosen on the oil pan and valve covers? My gauge says 55-60 psi, but I can't trust the accuracy of the gauge.