low oil pressure

[dan]

hey guys im baffled as to why my low oil pressure keeps coming on. did a oil change. has about 5 1/2 qts of oil due to high cap oil filter and when im rolling to a stop, i get a low oil pressure light coming on. i also have an aftermarket oil pressure gauge and it shows the same thing, it plummets close to 0 and sometimes justs reads 0. A few seconds later, it bumps right back up to 15 psi. what do you all think? need new oil pump or clogged oil galleys? the block was rebuilt about 5 years ago or so.

[DerekTheGreat]

Me thinks clogged galleries would lead to higher oil pressure. Could be you need a new oil pump or stuff is just really loose in the bottom end or cam bearings. When it hits 0psi do you end up hearing valvetrain noise?

[dan]

valve train noise has been going on for almost 2 years since i got the top end redone ( refreshed and ported heads). While cold the block is at 60 psi and when warm ranges from 10 - 30 psi in idle and while driving 35- 60 psi depending on how warm it is. I also forgot to mention i hear a clunking noise while decelerating from the engine bay. new motor mounts so maybe the oil pump might be loose?

[DerekTheGreat]

Sounds like the top end wasn't done right and needs to be done again, noise is no bueno. You could try replacing the pump but being that it's been driven with 0 psi and noisy I'm willing to bet it's rebuild time and that if you were to dissect the oil filter you'd find metal shavings.

[dan]

i still have the oil filter from the last oil change. i can probably dissect it later and see what i find. how would i go about to dissect it? just pry it open?

[DerekTheGreat]

Cut off wheel or hacksaw should do, right at the seam. Pull the filter media out and then open it up to see what's in it. Post pics. If there's metal in it you'd see it right away in good light, would glimmer like metallic paint.

[dan]

will do thanks. i also have a video of the motor running , not sure if i can upload it here. you can kind of hear the rattling on it.

[dan]

https://youtu.be/-rdTTK53jTE link to YouTube for the video

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[VicCrownVic]

Looks like a '90 or '91 if I'm not mistaken. How many miles on the bottom end? Also, what weight and type of oil are you running?

[gadget73]

Sounds like bad bottom end bearings. The pressure when cold, no pressure at hot idle is exactly what mine did when I got coolant in the pan and didn't change it before driving.
Vague possibility the pump is failing, but honestly I have never actually seen a V8 with low oil pressure that had a worn out oil pump. Its two gears that spin against one another inside a housing. Unless you run sand through it, there just isn't much to wear out.

[dan]

10w-30 and odometer doesn't work so not sure on exact miles. And the sound has been going on for almost 2 years, I'd assume if it was bearings, the block would be toast by now unless I got lucky and have a magic block? Lol

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[dan]

https://youtu.be/jDcPCQuMiro took this video right now after dropping my girl off at work

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[Tiggie]

At a highway speed cruise in OD, do you notice if the oil pressure changes with engine load vs coasting at the same speed?

[dan]

No stays at 40 but once I start slowing down to a stop is the only time it dips

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[DerekTheGreat]

...Vague possibility the pump is failing, but honestly I have never actually seen a V8 with low oil pressure that had a worn out oil pump. Its two gears that spin against one another inside a housing. Unless you run sand through it, there just isn't much to wear out.

This is what I was thinking. IMO the pump either works or it doesn't lol. I've seen videos where people slapped new pumps on but I never held much faith in their repair. Pumps move volume, pressure is generated from the resistance of the volume moving. Sloppy, worn out bearings will allow more volume through and lead to a pressure loss.

10w-30 and odometer doesn't work so not sure on exact miles. And the sound has been going on for almost 2 years, I'd assume if it was bearings, the block would be toast by now unless I got lucky and have a magic block? Lol

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I've heard stories of these things soldiering on long after the battle has been lost.. You can toast bearings and still have a good block. It's only when they crack or a rod makes a window through the side of said block that you've bought the farm so to speak. I'd try throwing the thickest oil possible at it, that Valvoline 20w-50 goop perhaps. Can't hurt at this point and I have been running it in my Fury for years.