More problems. Finally got the car running and now my oil pressure pegs out when I start the car. I havn't driven it yet for fear of blowing seals. Can anyone tell ne how high is too high? 90 RS, 305 TBI, running 20w50

 

First, I wouldn't believe the factory in-dash gage. The sending unit is prone to failure. Hook up a mechanical gage and verify what you have - or, just replace the sender and see if that changes anything.

Pegged = zero resistance. Also check any possible wire grounding (shorted) for that circuit.

And, there's no good reason for running 20W-50. That could cause high pressure when cold, but not pegging the gage. Switch it back to 10W-30, in any case.

 

With 20w50 oil you will peg the 60 lb gauge when you start the car, when the engine is cold. Why are you running 20w50 oil? Switch to a 5w30 oil and see how it operates. As far as causing problems the higher oil pressure will not cause any damage unless it gets over 100 PSI where it could burst the filter.

 

Mine always seems to be pegged when the car is cold (10w40 oil). It only comes down to "normal" when it's fully warmed up.

 

That's good advice. . . Mine is always pegged when I first start it. . . After warming it up for a bit, and drive a mile or two, it's fine. And I only use 5W-30 or 10W-30.

 

I run 20w50 in my car, oil pressure is 45 when cold and 30 when warm.
I am running thicker oil since I have almost 200K miles on the motor and it runs 25psi and 10psi on 10w40 oil.

 

Let's say in a mechanically sound stock engine, there's no good reason to use 20W-50.

If you have to use it to "fix" something, it's a crutch.

 

It seems to use oil when I run 10w30. Replaced the sending unit and it's now at about 45 at idle and yet again above 60 when driving

 

Maybe a dumb question, but did you put too much oil in?

 

I run straight 30 weight mobile 1 , 50 psi cold 35 -40 hot . It dropped to 0 and I had a heart attack but quickly pulled myself together and realized the car was running fine so I changed the sending unit and all was fine for about 6 months when all the sudden it shot up to over 60 and it's been there for 4 months , I'll fix it at the next oil change , never completely trust the factory set-up it's just a good reference .

 

My factory gauage reads in the red on the low side, and it has been that way since I got the car. I got a sending unit, it worked and then broke again, and it's back in the red on the low side. I agree, those guages are just a reference.

 

in my new 350 TBI im running 10-30 and i get about 45psi at idle and about 55psi while driving with my foot on the gas, in my old worn 305 before it blew, also with 10-30 i got about 30 psi at idle and about 45 psi while driving.