My oil psi is always between 40 and 80, i use 10w-30 regular oil, if i put 10w-30 synthetic or 5w-30 will it make my oil psi go down. The reason i was asking is because i read on another thread that the oil psi being that high most of the time could make my oil pump go out, or could the psi be that high because its brand new oil pump?
Thankx

 

I don't think it would affect it enough for you to notice.

 

If its a stock pump, with the stock pressure relief spring, it shouldn't reach any higher than 60psi. The spring will open the port and dump the excess oil. Is it a stock volume and/or stock pressure pump? Have you verified the actual pressure with a mechanical gauge?

As long as the last number in the oil's viscosity rating is "30", its going to have basically the same viscosity at 200*F. Doesn't matter whether its 0W-30, 5W-30 or 10W-30. The "30" tells you how "thick" it is at 200*F. The "-W" number tells you how thick it is at 0*F.