LOW...L0w...low oil pressure

[sassyrel]

I changed out my test gauge and hooked up a new out of the box mechanical one, and the best I can get out of it is 25 psi at 2500 rpm, 2 - 4 lbs at idle.



Ok, I took the oil filter off and I can see the regulator valve. I think it is stuck open, but not sure from this view what position it is supposed to be in. Should any of the hole in the valve be visable? I gently pried on it and I can't move it any to the left (as seen it the pic). I can move it a little to the right, but not far enough for the steel ring to touch the right side. It just seems to me that the steel ring should be against the housing on the left. Does anyone know from looking at this pic if it is stuck partially open? Anyone doing an oil change and could take a look at the position of your valve..... Sorry for the not so great cell phone pic...

Also, the filter bypass disc and spring (not shown in pic) are gone. From what I have read that shouldn't affect oil pressure, but it would allow oil to bypass the filter, correct?

Thanks alot for all the replies and help, much appreciated!!

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for some reason,,that looks diff, than my bros 89 he had?? buttttttt, if the regulator is stuck open,,you will have some pressure when the oil is COLD,,but zero as it warms up.. the oil is being pushed right out the bypass.. been there. you can get the bypass out,,if its there,,you just "unstake" the stakes that hold it in there.. polish the valve,,with a piece of steel wool, to get off any burrs, then put it back together,,and restake it, in a diff spot......after i did my bros, had wayyy good pressure...i know why his stuck open,,and thats another loooong story..

 

[OLDBULL8]

6.9 -- 7.3 oil flow.. Filter mounting pad showing the bypass, the 4 white dots are the stacking of the bypass valve. the square hole isoil in to filter, center pipe is filter screw on. This may help solve your pressure problem.

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[diezelcrazee]

I may miss-understand you your comment so bear with me.......There is no by-pass valve or spring in an IDI oil filter. The oil filter by-pass is located in the oil cooler header.

I have a 7.3 apart at home.....I'll look at the oil filter mount when I get home and report back.

Dave

Ok, let me see if I can clarify things a little. I am going to borrow oldbulls pic to try and show what I am talking about.

The thing I have marked as "oil filter bypass" in the pic below is what is missing out of mine. Will that affect oil pressure, or is that only letting oil bypass the filter with it missing? I know it needs to have it, but right now I'm trying to resolve the oil pressure issue. I have another parts engine, but it is a van engine so the cooler header is different. I did take the staked washer, fiber washer and spring out of the van cooler to see if it will work in mine. Do you know if I got all the pieces?

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The other square hole is where I can see part of the side of the oil regulator valve, as shown in my pic below. Dave if you can look and see how your regulator valve is positioned as viewed from the filter base side so I can compare it to mine it would be most appreciated.

I dont want to go through the grief of pulling the oil cooler off until I have looked into everything possible. Thanks again.

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Oldbull - thanks for the pictures.

 

[Dave 001]

I suspect that the missing oil filter by-pass parts have "flowed" down stream of the oil filter mount and are restricting flow. The parts are probably too big to actually flow into the block. Get a small magnet, stick it up the hole and to the left (by the oil pressure regulator, as viewed in your second picture). See if you can retrieve the by-pass parts.

Concerning the oil filter by-pass....it has three parts.....a spring, the fiber washer/valve, and a steel retaining ring. Install spring first, then fiber disk, then steel ring (then staked in place).

Concerning the oil pressure regulator....looking at your first picture.....it looks OK to me. Looking up at the regulator valve, the steel part that you see with the hole in it....it does not move. There is a steel plunger within this part that does move (to regulate pressure). Looking at the picture, it looks to me like the plunger is blocking the hole (as is shouold be) and not stuck open. This is why I think the missing oil filter by-pass parts have flowed down stream and are blocking the oil gallery.

I have an oil filter mount with the valves dis-assembled. I can take pictures if it will help.

It is actually very neat how the regulator valve works on this engine. The pressure regulator is monitoring the oil pressure down stream of the oil filter but dumps the excess oil up stream of the oil filter. Dumping the excess oil before the oil filter helps extend the life of the oil filter. The oil filter only filters what is going to the engine, not the excess.

Dave

 

[diezelcrazee]

Dave - that sounds possible to me on the missing by-pass parts. I'll do some fishing around in there and see what I can find. I'm trying to understand how this system works, so if you wouldn't mind posting pics of the disassembled filter mount and valves that would be great.

Thanks again for all your help.

 

[icanfixall]

I think you found the low oil pressure problem... Missing bypass valve parts. This has happened but not often around here. The missing disc, spring and wafer will not get pushed into the oil system. They are too large. My guess is when you changed oil they were sitting on top of the filter in the black oil hidden from view. Find any id engine. Hopefully the engine will be out of the rig so you can get at the filter base. If not just be aware of the oil thats going to be dripping down as you try to remove the staked in parts. A battery powered Dremel tool with a really small pointed burr on it will cut out the aluminum fast. Lay something down on the ground just incase parts drop and you need to start a search for them. You will be ruining the rear oil cooler header for the next guy too. Maybe "fix it" with a hammer so the next guy knows there is something amiss with it. A 4 pounder will do the deed easily. I know you wouldn't want to buy an engine and find out someone ruined the header oil bypass. Thats an easy thing to overlook...

 

[Dave 001]

Missing by-pass parts (as in not in the engine at all) will have no affect on oil pressure. This valve only opens on oil filter differential pressure. It has nothing to do with regulating oil pressure.

The fiber disc is smaller in diameter than the gallery that connects from the oil filter header to the main oil gallery (short passage about 2" long that is perpendicular to the crank). It WILL flow into this gallery. It WILL NOT, however, fit into the main oil gallery (gallery that runs the length of the block). I have a 7.3 on the engine stand and I just tried it.

Why distroy a good oil filter header? Just swap the entire part and forget about grinding and Dremels and making an even bigger mess.

Dave

 

[diezelcrazee]

Had to move the truck out of the shop to do some work on the daughters Mustang, am going to try and put it back in there tomorrow and pull the filter again and see if I can locate any of those missing bypass valve parts. Thanks again for the help.

 

[diezelcrazee]

SUCCESS AT LAST!!!!!!!!11

Thanks to everyone for the help, but I have to especially thank member Dave 001. He took the time to email me photos and detailed explanations of a disassembled filter/cooler head and the disassembled oil pressure regulator valve. It was with his great documenting of the working of this valve and system that I was able to see that the regulator valve was slightly stuck open, and with a pick working from the oil filter head side I was able to get the valve unstuck. Now it has 35 psi idleing and 45 psi at 2500 rpm. Thanks again Dave!!

 

[racer30]

Good job gettin that fixed. Just shows how much help you can get from the guys here on this site.

 

[icanfixall]

Now if that bypass piece is still missing know this... You are sending dirty oil into the engine bearings. Don't do that for long either..

 

[diezelcrazee]

Now if that bypass piece is still missing know this... You are sending dirty oil into the engine bearings. Don't do that for long either..

Yea I know, I bought this truck about 3 months ago, no idea how long that thing has been missing. I have the spring, fiber washer and steel washer I took out of my parts engine. I intend to change the oil and fix the bypass before I get serious about driving it. Thanks