Man, I love my Z28, but I think it will nickel and dime a dude to death sometimes. Over the last week the oil pressure on my LT1 has been eratic. Normally it is....

22psi@800 rpms
40psi@1500rpms
50-60+@3000rpms and up

The oil pressure has started to jump around, mainly going up. I first thought no big deal, just the oil pressure sending unit. Well, I changed it and it has not solved my problem. It is now constantly 20psi higher throughout the entire rev range....

40psi@800
60+@1500 and up...never seems to go above 65psi

This problem has me really worried. I realize my oil pressure gauge could be screwy. I plan on replacing the entire gauge cluster in order to get my trip odometer fixed, so I may have that issue covered.

From what I have read here, I could have a spun bearing. There are many references for low oil pressure, but not many for high oil pressure. Not making my troubleshooting easy...So far it has not made any noise out of the norm. I can't really say it's lost any power because I can't really get into it good due to my ailing T56. If it is a spun bearing, how to find it? Should I just look at the oil or slice open the filter? Could it be the oil pump? Can the oil pressure relief valve in the oil pump get in a position to cause high pressure?

One of the Chevy dealerships has a machine that will completely clean out and flush the oiling system. It hooks up in place of the oil filter(I think). I had it done one time, a mechanic I trust there says its a pretty good cleaning system. I noticed no problems after having it done over 3 years ago. I'm thinking on doing it again to see if it is a clogged hole. The thing that bugs me there is that I have been religious in keeping the oil changed, using AC Delco filters, and using Castrol Syntec 5W-30 or 10W-30 at that.....the holes should have no reason to get clogged......right?

I have yet to check the oil pressure at the Aux oil port above the filter with a mechanical guage. I think I will do that next to see if it my dash gauge is correct......

Has anyone been through this problem? Any advice or opinions are welcome please.

 

well, that has me. i don't know what kind of oil u use, but try some 5 w30 or something really light to get the pressure back down a little.

 

I don't think you should worry so much. Having nice high oil pressure is good. Mine stays at about 60 before the oil warms up. Once it warms, it idles right above the 20 mark, and goes between that and 40 during normal driving, and will go higher at the higher RPMs. I personally don't think your oil pressure seems to be out of wack. You really should worry about low pressure, which is what would happen if something was leaking or clogged. High pressure is def. GOOD. (of course not TOO high)

 

Thx for the responses so far, keep em coming. For over 5 years, my oil pressure has been 22psi @ idle when warm. Now it is 40 psi @ idle when warm. I wished I could believe that nothing was wrong, however, for such a change to suddenly happen, I believe something is wrong...I just don't know what.

 

ttt....anybody else had any experience with high oil pressure?

 

yeah dont trust an 8-9 year old guage. Get a mechanical one screw it into the unused port above the oil filter pad in the block and see what the pressure really is.

 

Right, buy a mechanical gauge and hook it up to the pot above the oil filter, set it where you can see it then start it up and confirm oil pressure, pressure increases because of restrictions.