Ford Powerstroke 94-98 7.3LDiscussion of 94-98 7.3 Liter Ford Powerstroke Turbo Diesels
Hello. I have a 96 PSD with a 5 Spd and have a slight problem I have not been able to get fixed.. The truck as absolutely no oil pressure coming out of the LPOP. I took the oil filter off to see if the ... JOIN NOW TO REMOVE TRACER
Hello. I have a 96 PSD with a 5 Spd and have a slight problem I have not been able to get fixed.. The truck as absolutely no oil pressure coming out of the LPOP. I took the oil filter off to see if the pump was even moving any oil and did not have a drop come out. I took the oil pump off and looked it over, didn't have any excessive wear or any problems. So I put that back on and jacked the cab and the engine up so I could get the pan off and get to the pick up tube because I was told that those sometimes crack or come off. I have it out and I looks perfectly fine. There are no holes in it anywhere and we put some soapy water on it a covered the two ends and hit it with some air and there were no signs of any leaks. So now I am at a loss. I have no idea what else to check. I have checked all the usual stuff that goes wrong with these and have it narrowed down for sure that there is no LPO. Does anyone else have any other ideas? Also I was looking for the specs on the clearances on the oil pump to see if maybe it was worn too much and I just couldn't tell but I can't find them. Does anyone know what they are or where I could find them?
Since it was driving down the road when it quit, and now there is no oil coming out of the oil filter housing, I have to wonder if there isn't a component somewhere in the oil system that can bypass or relieve all oil flow back into the oil pan. After getting it home, he filled the HPOP reservoir and it ran fine until it ran out of oil in there. While it ran, he noticed there was no engine (LPO) pressure and that is what led us to finding that the LPOP is not pumping any oil at all.
Any help you can provide with the low pressure oil pump specs or low pressure oil system design / components would be greatly appreciated.
The oil pump and front housing look so beautiful and clean we didn't want to just replace a good part... There are no gouges or marks in the gears or the housing. The truck does have just over 300K on it. But I wouldn't think it would just stop working all of a sudden like, thought it would be more of a slow wearing out?
We found it!!!! But now how do we fix it? . . . .
Ok, thanks so much for the replys and info! Now for all the questions:
We got the LPOP out and it looks great. My boy even went to Ford and looked at a new one. This one shows almost no wear so I say use it again (Especially as easy as it is to change.). The housing and front cover look great too! So then we proceeded to pull the pan to see what the pickup tube was like. Before we got it out we thought it had a crack in it's side. Just jacking up the engine isn't enough to remove the pickup tube. We had to jack up the cab about 2 inches. Then jack the engine up higher (As far as it will go against the fire wall!) and you can drop the pan far enough to snake the pickup out of there. The pickup is fine (Just as he stated above). So we have been trying to find what failed. While I agree with replacing worn parts, so far I don't think any of these are worn enough to warrant replacement. The other aspect of this I had a problem with is that this was a sudden failure. The day he was driving it everything was fine (Except for a possible sensor or wire issue). Then it suddenly had no oil pressure and of course won't run anymore. This is why I said we were looking for a failure and not worn parts.
We can't seem to find any repair manuals on this. He went to the library and all of their books show what I would describe as a conventional gas engine oil pump located in the oil pan and driven by a shaft. I don't understand what that is all about. I wouldn't think that we have the only one made this way! (If I need to post pics of how this pump is made, just let me know! We would be glad to do so!)
So, we got the idea of using compressed air to test the oil passages to / from the oil pump and oil filter. When he hit the oil filter inlet as I was trying to block the pump outlet passage, I saw oil run out of the block just in front of the front main bearing, on the drivers side. When I got a light to see up in there, I could see the threads on a plug that was about 1" in diameter. I could also see the center of the plug was drilled out and had a one-way spring clip holding something in it's center. I had him hit it with air again and saw the oil splashing / bubbling from near the bottom of the threads of the plug. I reached up in there with my small finger and the plug LEFT!!! I tried to get it out with a grabber tool and a magnet and it won't fit out between the block casting and the front cover.
I feel that this is a pressure relief valve (Or whatever it is called!) and so it would be good to know where it goes and if there is any installation procedures. I would not want to pull the front cover of the engine to find out it wasn't necessary. As best as I can tell the cover has to come off to re-install this plug. But I would sure like to hear from someone that knows or has a book to read the pictures in!
Anyone have any ideas / advice?
Oh, we marked the pump gears; but, how could you install them wrong? Just looking at it, it looks to be fool proof (Unless that is the gear that is marked 'Out' on one side. Only one gear was stamped this way.).
The other question I came up with was have any of you ever seen a cracked pickup tube? I have heard of some, but when I mentioned the above to my professor, he had to wonder if that isn't what was wrong with his brothers. It would loose oil prime if it sat for a few days. It it ran each day it would work fine. I think this plug could have been backing out and become very loose. Maybe it hadn't just fallen out yet. . . . I don't know.
Last edited by millco; 05-25-2010 at 12:08 AM.
Reason: Automerged Doublepost
Truthfully, I have had pretty good luck cleaning well and re-sealing with gasket maker (the style the OEMs are using originally now days anyway). There is enough room to be able to clean in there and get it re-sealed. I think from what we have to do to it so far, that this will be one of the easier pieces to the puzzle.
I don't know: As I get older, I do like to do the best job I can but I also look for short cuts too. Seems like there is less time to be able to get all these things done. I just did injectors on my Cummins and a guy suggested I leave the fuel lines attached to the common rail and pull the them all as one assembly. That was good advice! Saved me quit a bit of time vs. having to deal with each line individually.
Since I have had good luck with re-sealing pans in the past I would recommend to anyone that it would be better than having to pull the engine out. Like I said, only because it can be done fairly simply and will save quit a bit of time. I would never recommend something if it didn't have a good chance at success though. It just isn't worth going through most things to find out that it won't work. I don't know why; but, I have a real strong dislike for having to redo something. Always have and most likely always will!
I know very little about what is involved with doing this repair.
For me, a decision is seldom black and white. I always try to consider the risk/reward.
If you are working on your own stuff and think you can do it by cutting corners, consider the reward if it works. If it doesn't work, are you really risking that much? What you learn by being wrong or right may be worth the risk alone.
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