Hey guys, it’s been quite some time since I’ve been on here. But I have another 7.3 question for you.

background on the truck is it a 95 crew cab Auto. Had new injectors about a year ago from Rosewood we installed. In general the truck has never given an issue whatsoever outside of blowing up a few transmissions. Has ran great every day fires up and -20° weather, etc.

So here’s what I ran into. We have nine of these trucks for our Forestry business. My guys came home. Truck ran great parked it. Next morning doesn’t start nothing out of the ordinary simply did not start hooked up a computer to it. Everything checks out buzz, sensors, etc. However, high-pressure oil pumps shows zero oil pressure. so jumping the gun, I order new pump we throw the pump in fill up the reservoir fires up for about three seconds shut off. Inspect the reservoir it’s empty again fill it up same thing.

mind you when we replace the pump. The reservoir was dry, which was also odd.

So we throw a gauge down on the 1/8 npt port of the filter housing and have nothing there. Zero psi. Inspected the check plug and spring on driver side of the head. Everything looks good. At this point we know we are not making anything for low oil pressure verified by gauge and inspection. all I can think of that’s left are the low pressure oil pump. We pulled that it looked absolutely fine, still throwing a new melling I have on the shelf in it, since it’s off. Secondly, possibly a cracked pick up tube in the pan. I find this hard to be the scenario since it just seems odd. It would just crack and completely fail overnight. Rolled the truck outside had it on a steep slope, also jacked the rear end up with the truck over full probably 3 to 4 quarts still made nothing for oil pressure during this period of time. (Poor man’s tube test?)

We actually took the filter off to see if anything was squirting out of the filter housing and still had nothing. So this leaves me at the last possible scenario. I’m not quite sure how oil could be bypassed directly into the pan off the filter because the little 8th inch npt plug had zero oil behind it or pressure(dry behind it). I do know there’s the regulator valve inside the oil cooler filter housing.

is this possible that that’s hung up? I only thought of this is because of about a year ago my buddy shop resealed the cooler and the dip **** who did so forgot to put that valve in the original housing. They had to replace the entire housing because the truck was making zero oil pressure.

so my question to you is I find it hard to believe that the tube is cracked or fell off with the truck that was running 100% perfectly fine it’s parked next morning there’s nothing so I’m trying to find the culprit of our low pressure oil issue. I’m gonna pull the cooler tomorrow, since we had a radiator for the low pressure pump but I guess I’m still trying to make sense if the relief valve or regulator valve inside the filter housing

Can it actually do that? Are the mains getting fed oil? If it is stuck open or are we ruining the bottom end right now from starvation?

I’m going to drop the oil and throw a camera up in the pan as well but I do not believe this is going to solve or allow me to even see anything if I’m lucky.

Coolants clean no codes I’m just not making low pressure oil and this is a first I’ve ever seen this on Truck

 

I recall a while ago that someone was having trouble with low oil pressure even after installing a new oil pump. Turned out he had a scored front cover where the pump runs against. If I remember right, he had to install a new front cover. The valve in the oil filter housing can't fall out unless the filter housing is removed. I suppose the spring in that valve could break and cause no oil pressure, but I don't recall that happening to any one. I have heard of some one having a hell of a time getting a new oil pump to prime, but that might have been the guy that had the scored oil pump housing in the front cover.

 

thank you front cover isn’t scored.

new pump made no difference

 

Bumping your thread back up to the first page. I'm curious to see what the culprit was here. Hope moving the thread back up top will get some more visibility on it and maybe a helpful suggestion.

I see you have a separate one going on the 99-03 forum. Any luck with the issue yet?

I don't really have anything useful to add other than I think I read in some other thread about the filter bypass getting hung up in the housing. But I would think that would cause either normal pressure and just bypass the filter, or an excess pressure, and I believe that's what happened in his case (blew out cooler o-rings).

This thread, somewhere around post 136: https://www.ford-trucks.com/forums/1...ispreloading=1

Good luck getting to the bottom of this issue.

 

95 can lose a valve when changing the oil filter

The oil cooler can do it as well if the internal regulator gets stuck

what to look for
https://www.ford-trucks.com/forums/1...***-valve.html

 

I had little bit of visible oil in coolant in my 95. Figured it was oil cooler. Rebuilt oil cooler with new tube and orings. Put it back together. Went to flush cooling system and upon startup noticed large amount of oil in coolant now!!! Thought I rebuilt it wrong or ring ripped. Pulled it apart and realized it was a damaged bypass spring valve in rear head unit where oil filter and block heater connected. Purchased a new one. Put it back together again. Then went through a 3 day long flushing process to evacuate the oil contaminant in my cooling system!!! What a chore. In my case the valve was damaged and didn’t keep the oil separated from the coolant. The original orings were not damaged or ripped.

 

I wanted to follow up on this thread. I pulled the oil pump put in a new mailing front cover was not scored pulled the oil cooler. The relief in the oil cooler was not misplaced.

we ended up pulling the motor front cover and oil pan. Pick up tube was fine and when we popped the front cover of the relief valve that is right after the outlet of the low pressure pump was sitting in the cover I’ve pictured this below it specific to 96s. Hopefully this will help somebody else out, but yeah, motor had to come out all over this little **** plug, I check the valve in the top of the cover, which was fine






so in six hours, she was out resealed fixed and back in

 

Thanks for posting the cure to your problem.

 

6 hours? That is movin’! Glad you got it fixed

 

Thanks for posting the resolution. Forgive me for not knowing. But what does that valve do? I've done a lot of reading on these, but don't recall much mention of this valve in the timing cover. Is it just some kind of a one-way check valve? And any idea how or why it would have come loose and worked its way out?

Thanks again for sharing. Glad you finally got this resolved.

 

That would have taken me a week. Good job.

 

Yes I have done this many times before :-) started at 6 with an assembled truck when I got home. Stopped at midnight when driveline was complete. but its not completely done, want to blast it with the hotsy and replace the body mounts on the core support. Steering gear has leaked for years, so that's nice and easy right now.

I've never seen this before though!

Its just an old logging work truck. Goes to work every day, the frame has been broke in half before between the leaves, (fishplated and been solid for 4 years since)

Just an old beater ford, literally drove home and the guys parked it, never started the next morning or again...effn plug fell out.

 

Yeah its a one way check with a ball/socket/drain orifice. This one only exist in the 96s if I am not incorrect. I do not know why they were put in. After we put it back together I should have just thrown in a plug, its red lock tightened in now...I don't anticipate it ever coming out again.

 

You do it enough you get better and better.