​NO OIL PRESSURE

1988 F-250 NA 7.3 Idi

This is also posted on oil burners

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 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.

 

pictures of oil pressure valve thing

 

By the pictures I see nothing that would cause no oil pressure.
maybe there is a piece of rtv blocking the oil pressure sender port?
Where are you drawing oil pressure from, drivers side at the oil filter, or top rear of the block ?

 

Top rear of the block

 

Im curious what is causing this when you find the smoking gun. I think the next step is to remove the drain plug and drain the engine oil. Then shove a borescope inside the oil pan and look at the oil pickup screen and look for any cracks at the oil pickup tube.

 

I would also put a gauge at the oil filter port and see if it has pressure there.

 

Well. Bad news, I tried a plug in the main oil gallery. When I unthreaded it, a little oil came out, and I threaded in my mechanical gauge… started her up, no oil pressure. I ran it for a total of 20 seconds, and idled it up too. (I don’t have the radiator hooked up right now so I didn’t run it longer)

 

Sounds like either the pickup is blocked, or the oil pump said "I don't want to play nice any more"

 

Yeah, and either way one has to suspect the main and rod bearings now, after running without oil pressure.