Oil starved, odd oil pressure readings

[GinsuGuy585]

I changed my oil a week ago to synthetic (high milage) and now a week later, my engine is sounding oil-starved, and my oil pressure guage is taking longer than usual to drop.

When idle, the pressure is just below 60, and a 2-4 second rev brings it up, but then when the engine returns to idle, it takes longer than usual for the pressure to drop, and as the needle is moving down the movement isn't smooth.

Details:
The oil starved sound is really apparent, there is considerably more high pitched noise when accelerating (rockers and lifters), and I think I remember the 3800 having oil lifters, if I'm right, then the lifters aren't providing enough lift, and making the higher pitched noises.

Anyone know where the oil pressure sensor is in relation to the pump/filter, or have previous issues with synthetic oil?


EDIT: Yes, I checked the oil level, it is right on the full line when cold. Also checked all the other levels, and it's not thirsty for anything.

[GinsuGuy585]

Re: Oil starved, odd oil pressure readings

Anyone have the service manual that can look this up for me? Knowing the flow path would help a lot.

[auto666]

Re: Oil starved, odd oil pressure readings

what wieght did use

[ssms5411]

Re: Oil starved, odd oil pressure readings

Using RP 10w/30 and no problems, fires up to above 60psi at start and when hot drving around 30-40psi and 60psi WOT.

[GinsuGuy585]

Re: Oil starved, odd oil pressure readings

10w-40 Valvoline max life synthetic.

Before that I was running mobil1 10w40.

Usually I idle about 1-2 needle widths below the middle mark (middle = 60) and around 2k it moves about 3 needle widths above 60 (around 70 I'm guessing)

now it's moving up smoothly to a little past 60, and moves back down in 2 jerky steps. (drop, pause, drop, pause, drop)

I've never seen something like this before, but I can definitely tell the lifters aren't filling properly, the telltale rasp, and sluggishness past 1/4 throttle.

If ANYONE knows the oil flow layout of the 3800SII please tell me. I don't want to buy the service manual for this.


EDIT: not throwing any codes, and all other engine stats look within range (obd2 pro-scan reads everything, even does mpg stats based on fuel trims)

[ssms5411]

Re: Oil starved, odd oil pressure readings

I would check all your vacuum lines to make sure their fine.

[auto666]

Re: Oil starved, odd oil pressure readings

you could have an oil pressure relief valve acting up a motor flush might be in order

[GinsuGuy585]

Re: Oil starved, odd oil pressure readings

Where is the oil relief valve?

I'm going nuts... still trying to find the problem.
Vacuum -fine
Plugs/wires - fine
Gaskets - seems fine
Oil system - still something amiss, but no free time to do a major tear-down. (8th week of class)


Again, if anyone has a detailed 3800 diagram I would really love to see it.

[95 l-32]

Re: Oil starved, odd oil pressure readings

if its making a squealing/squeaking sound it sounds like your loosing your main bearings and the pressure building and not dropping means a bearing has spun on the crank and is blocking the supply hole , when the roller lifters go they tick and clack andif they stick in the bore the ussually stick in the open position causing the motor to backfire or miss, and if they stick in the closed position they will break the camshaft .