deadeyejedi

wondering if i could get some advice on my oil pressure gauge ? i have the factory oil pressure guage in my 1976 cutlass supreme 455.it generally runs around 70 lbs of presure at startup when cold, then will settle back to around 40 lbs once warmed up but, with the needle boucing back and forth .in gear, warmed up, in traffic,at a stop light it will drop to around 30lbs.ive noticed when i shut the car off the needle will stay at 40 lbs until i turn the key on again, then it will drop to 0 until i start the car again.do you think this is a sending unit issue ?or is the gauge itself failing ?or possibly wiring to the gauge issue?this bouncing fluctuating needle is driving me batty .thanks in advance.

MDchanic

Staying put when you turn off the car is normal operation for factory gauges.

Varying between 30 and 40 psi with RPMs indicates good oil pressure.

I'm not sure I understand what the problem is.

- Eric

oldcutlass

I would be more worried if it drops to 0 and stays there while its running. Its like the fluctuating fuel gauge, As long as its moving your good.

deadeyejedi

thanks eric . wasnt sure if the staying put was normal at shut down. i assumed it would drop to zero at shut down .so i guess the biggest problem is the needle bouncing all over while driving .it does settle in at times but ,then starts jumping .

deadeyejedi

so i guess i wont worry about it too much then. thanks Erics!

MDchanic

You could always put a mechanical gauge on it and see whether the pressure really does jump around.

A bad connection is not out of the question, but nothing you said above sounds odd.

- Eric

deadeyejedi

Will do

cwb442

My aftermarket gauge(auto meter) moves in direct correlation with the rpm and at idle after oil comes up to temp it will actually bounce around with cam lope. But as mentioned as long as it's moving should be ok.