No Oil Pressure on 7.3 Idi

[Paulalanrade]

NO OIL PRESSURE
1988 F-250 NA 7.3 Idi

Hey, first time on here, but the info seems very useful. Disclaimer, this truck has been daily driven for a year, before that, it sat in a barn for over a decade, it was my grandpas, and he parked it only because he got a new truck.

First off, I have an aftermarket electric oil pressure gauge in my cab, yes electric, there’s no oil line that runs to it.

I have this electric gauge on a T fitting in the stock oil pressure sender location, in addition to the stock dummy switch.

I have also verified with a mechanical gauge that I do have no oil pressure.

The story: I was about to leave for the airport and saw my check engine light was on, I thought, eh, it does that sometimes because the switch is kinda junk/bad ground, but then I saw on my aftermarket gauge 0 oil pressure. Oh boy, “Maybe my aftermarket gauge isn’t working” I prayed to myself, and left for the airport at about 1:30 am. Oil level was perfect, and no large oil leaks. I made it to the airport and on the way my gauge got up to 10 psi, at 2800rpm. Once back to idle, I had nothing. In the parking garage I thought heard a small ticking sound.

I enjoy my trip, and get back to my old gal, fires right up after a week, and still says 0 oil pressure. On the way home, I get to about 8 on the highway, then once I’m just cruising through town, back to basically 0, and I think I heard a small tick.

I get it into the shop and yeah, a mechanical gauge says 0 psi.

I overfill the engine by 4 quarts, check for oil pressure, nothing, then I jack the rear up a foot, still nothing.

I next drain the oil, no signs of a bunch of metal, and I can see the pickup tube is still there, and solid by poking with a screw driver.

Then I take the filter off, and yes the bypass valve works hard, and the pressure valve spring deal is not stuck.

I now have the oil cooler off, and somewhat taken apart, I did not pull the engine for this.

The passages for the oil inside the cooler are a tiny bit rusty, this truck sat in a barn for 14 years, and there is some rtv or something blocking a couple of the passages, just a little. With it apart, the pressure valve deal pushes in, to allow the holes to align up for passage, and springs back shut.

I feel that the tiny bit of rtv is not causing 0 oil pressure, hard to believe. I don’t know what to do from here.

 

[Paulalanrade]

Photos of pressure valve thing

 

[IDIBRONCO]

Right off the bat, did your grandpa put a new engine in it or have someone do it? I ask for a simple reason that has a complicated answer. I'll try to keep the explanation relatively simple for now. There's two oil galley plugs at the front of the block, right above and slightly to each side of the camshaft. They're pressed in from the factory and they get held in by slight deformations of the metal that surrounds them. A lot of rebuilders, even really big companies, will remove them and not realize how they're actually held in. If not held in like the factory did it, one or both can and probably will fall out eventually. Oil pressure pushes them out of their holes. When that happens, there goes your oil pressure.
Your back story made me think of this right away. The only way to access those plugs is the remove the front engine cover that's behind the water pump. Not a quick, easy fix.
Also, you're right. A couple of tubes being blocked by RTV won't make you have no oil pressure.

 

[Paulalanrade]

Right off the bat, did your grandpa put a new engine in it or have someone do it?

This engine has never been opened internally and has not had any amount of rebuilding. It has 127,000 original miles. He bought it new.

 

[Nero]

So lets clear the air here... How many miles did you drive with the gauge showing zero oil pressure? Because if it was more than one, you would have had a glitter bomb in your oil pan, spun bearings, and potentially a locked up engine.

How did you verify oil pressure with your mechanical gauge?

 

[Paulalanrade]

Out of 200 miles, my electric aftermarket gauge said about 2-3psi for probably 60 miles, it’s hard to judge since the gauge goes up to 60 psi. I never checked with a mechanical until I got it back to the shop, I threaded it into the stock location of the factory oil pressure switch, and the gauge did not go up at idle or at high rpm

 

[Paulalanrade]

Also, if I don’t thread anything into the stock Location for an oil tester, and I start it with nothing threaded in, not a drop of oil sprays out. I certainly have low oil pressure, last year when I got this running, a lot of oil would come out of that area if I unthreaded the oil pressure switch

 

[franklin2]

Also, if I don’t thread anything into the stock Location for an oil tester, and I start it with nothing threaded in, not a drop of oil sprays out. I certainly have low oil pressure, last year when I got this running, a lot of oil would come out of that area if I unthreaded the oil pressure switch

Even with low oil pressure, you should have something coming out of that hole with nothing screwed into it.

Let's see if the guys on here know of another port you could undo to check for oil pressure. I think there is another one somewhere that they use when they add a turbo. Maybe you could check for oil there.

You would think if you truly did not have any oil pressure, you would have heard it and the engine would have eventually locked up.

 

[WMO4IDI]

Also, if I don’t thread anything into the stock Location for an oil tester, and I start it with nothing threaded in, not a drop of oil sprays out. I certainly have low oil pressure, last year when I got this running, a lot of oil would come out of that area if I unthreaded the oil pressure switch

Sounds to me like the oil passage is gunked up.

I'd try a bit of Sea Foam & a pipe cleaner to get the big stuff out of there, then put the rest of the can in the oil, run it a few minutes and flush it. I'd clean out the sensor as well...

Then comes the possibility of finding new oil leaks.

 

[WMO4IDI]

Let's see if the guys on here know of another port you could undo to check for oil pressure. I think there is another one somewhere that they use when they add a turbo. Maybe you could check for oil there.

There's a port on the oil filter head, I forget if it's 1/8" or 1/4" npt.

 

[IDIBRONCO]

Let's see if the guys on here know of another port you could undo to check for oil pressure. I think there is another one somewhere that they use when they add a turbo. Maybe you could check for oil there.

The most common location is on the bellhousing part of the block right behind the oil filter. It takes a 9/32" square socket to remove it IIRC.

 

[Nero]

It sounds like you're testing it right, I second the port is probably plugged internally.

Try this other port here, see if you get different results. I bet you have oil pressure. With only 3psi your engine would have been toast after a few days of driving.

You must be registered for see images attach

 

[Paulalanrade]

Alright, I will try a different port, and clean out the engine the best I can. I first have to order some new seals and o rings to put all the junk I tore apart back together.

 

[IDIBRONCO]

Try this other port here, see if you get different results.

At least you have an engine on a stand to take a picture of the plug. Each time I mention it, I wish I had a picture to post.

 

[Black dawg]

If you end up not having good pressure at the other port, put some air (with a rubber tip blowgun) to either one of the ports (with the other plugged) and you should hear if an internal plug or piston oiler fell out.