Hey guys, I just did a new oil change because I noticed that my oil pressure had been dropping very low when I came to stops. Brand new oil and oil filter and shes still doing the same thing. Does anyone know why the oil pressure would be dropping so low when the rpms drop? Thanks

Two things 1) Have you checked your oil pressure sending unit and replaced it? 2) I had trouble with my oil pressure indicating low until I pulled my instrument panel out and cleaned the contacts on the electrical mating surfaces that feed it. Since then, my pressure has read up in the band. The dash is interfaced with a plug and it can get a dirty contact.

my bosses 89 did the same thing till he replaced the sender

Is replacing the sending unit an expensive job? And is recommended?

no it's not expensive i've done it in my 91 chevy.tk bout 15 mins and i was done. it's rite at the back of the intake below the dizzy.had to buy the speacil socket to remove the sender but that was it.
[sp]

Just use caution and care when removing the sender. The brass fitting that it fits into can easily be snapped off. That would be the piece that you see the hose attached to.

Yes I would try swapping it out. The sending unit is mounted just behind and down below the distributor and the purchase of the special socket m akes it real easy to do. If there is enough room it can be done with a box end wrench, but that is not often found. I have replaced the one on my truck a couple times, until I found the problem with my gauge cluster electrical contacts. A cleaning of the contacts solved my problem.

If it drops to about 20 pounds or so it will be fine, every 350 does it my brand new 350 in my 70 GMC runs 55psi all thetime but warm idling it runs around 20. its because the sender is at the top of the block and all the oil cant get up there.

I posted the same question a few months and took the advice for replacing the sending unit. It was cheap and fairly easy. I say fairly easy because there was a fair amount of stuff in the way.

Problem solved on my end.:metal:

Is the pressure dropping below where it did before or is it just low? A while back, I was a bit concerned with my hot idle oil pressure. The needle would jump right back up when I got on the throttle but dipped very low at stop lights. I asked an engine builder friend of my about this and he said pressure should be around 10psi / 1000 rpm.

10psi at a 1000 RPMs, is not what I would call a strong pressure.....adequate but not great. Now 30 psi at idle is more around my experience in oil pressure and up from there at highway RPMs. Depending on the motor's age and oil pump design, the highway pressure can be 35 to 60+.

These models of truck haave a definite oil pressure sending unit problem and the elctronics is weak in completing the circuit to the driver. When my gauge showed a problem, I hooked up a mechanical pressure gauge at the motor and measured my pressure directly. That way I knew what I had for sure and then worked to get the instrument panel to match.

Ya, mine drops right down after my engine has heated right up, and i have come to a stop at a stop light or whatever. Then as soon as i hit the throttle, it jumps right back up to where it should be - i just thought it was alittle suspicious because i has not always done that

if you have changed out the intake gaskets,and didn't put a rag or paper towels in the lifter valley to catch the carbon or scarping from the gaskets you could have a plugged oil pump pickup [ask me how i know]lol.i paid a guy to change out my gaskets he did a great job but didn't put nothing in the lifter valley to catch the scarpings,all went to pan.i noticed rite away that my oil pressure was low dropped pan plugged pickup.cleaned pickup and changed out pump[seeing i have 310000 miles on mine.oil pressure was back up.so check your oil pickup.