oil pressure question on a 6.2L

[tehbald]

hey all, i have an 83 GMC 1500 with a 6.2 n/a with a 4 speed stick. since i have gotten the truck the oil pressure guage has been fluttering up around 80psi. however, the pointer never stayed in one place. all of a sudden the other day it kinda crashed and now when i run it, it sets right around 20psi and sets steady. i have looked the pressure up on alldata and it says that normal pressure is supposed to be around 36psi and i am not quite reaching that except for when i first fire it up. i am currently running 15w40 rotella oil. i have not yet had the chance to put a mechanical guage on it to see what it is truely running but i was curious as to if anyone has experienced this before. best i can tell this is a bit of a high sludge motor but i have been doing early oil changes along with some ocational BG products to help eliminate this problem. any insite on this would be appreciated.

thanks,
scott

[tehbald]

well just to update, i have put a mechanical guage on it and i am getting roughly 60 psi out of it. installed a new pressure sending unit and still less than 20 psi on the guage. so i guess this means that the guage itself is bad. has anyone else had this happen? is there a way to correct this diriectly or do i just need to get a seperate guage?

[ksukats57]

well just to update, i have put a mechanical guage on it and i am getting roughly 60 psi out of it. installed a new pressure sending unit and still less than 20 psi on the guage. so i guess this means that the guage itself is bad. has anyone else had this happen? is there a way to correct this diriectly or do i just need to get a seperate guage?
IIRC the 82 has seperate gauges (not all in a cluster like on newer s . tuff) that you would be able to just slap a new one in its place. Asuming your wiring is all good from there to your sending unit, id just try that.