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Another 7.3L Phantom Oil Leak - Please Help!

8K views 38 replies 11 participants last post by  Para_Bellum 
#1 ·
Hi All,

Long time reader of the forum and have finally joined hoping you all can help me. I have a 2003 F250 with the 7.3 that I recently bought and have been addressing all the small things it needed.

My issue is a slow oil leak that I cannot find to save my life: the leak is just enough to drip off and make a mess on my driveway, not a puddle by any means but it's annoying and I don't like leaks - the drip is coming from 2 points - the bottom center of the bell housing (running down from above) and the two steel lines below the starter (passenger side, to the right of the bell housing).

I've already looked all over the forums and checked about everything anyone has said to check - the HPOP is good (already serviced), the turbo and pedestal are dry, valve cover gaskets are good, oil galley plugs are dry, dipstick tube and oil pan are good, rear main is good, oil pan gasket is good, no oil in valley (so none running down from there).

Based on what I've read and looking at the truck, this looks like a leak somewhere on the passenger side, rear of the block, running down to the bell housing then as the drip hits the bell housing it's running around and dripping off the bottom. I've looked with lights, mirrors, etc and can NOT find the source of the leak - even when running I cannot see any actual leak (so it's not obvious when under pressure) - but at the same time, if I clean up the bell housing and starter, then park it for a few days, I'll have a few drops again in the same spot, so it seems that it's not a leak under pressure, just a very small leak. I thought it would be the oil galley plug/o-ring based on the location of the plug and running down to where my leak is, but the plug is dry.

I'm starting to lose my mind looking for this- any help would be GREATLY appreciated.

Thanks!
 
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#2 ·
I would do three things -

First, I'd clean it to within an inch of its life - brake cleaner, degreaser - whatever you have to do to make sure all old oil is gone.

Second, get a vial of fluorescent oil dye. Carefully pour it in with maybe a 1/2 quart new oil and run it for a few days.

Third, go out after dark with a UV light and a pair of yellow glasses (you can rent them at Autozone) and start looking. Your leak trails are going to be glowing.

I suspect you've got a few pan bolts loose in the back. That's actually pretty common and will cause that drooling around the back, especially behind the starter distribution.

One thing to keep in mind. The "joke" that these trucks like to mark their territory has a basis in fact. I'm not sure any of us don't have that same exact stain in our driveway. You learn to live with it....
 
#4 · (Edited)
Thanks RT I have already cleaned it as you suggested, which was a huge help in identifying my other leak at the HPOP, I did wonder if my pan bolts are not properly torqued, I can see a VERY small bit of oil on several of the bolt heads so I will check that - would loose pan bolts at the rear cause the rundown leak at my bell housing and starter though?
 
#3 ·
A spot that loves to leak in that area are the high pressure oil rail plugs on the backs of the the heads. You'll need a inspection mirror to see them, they have a 1/2" square recess in them to remove them. There are also the same plugs on the front of the heads for a total of 4 of them.
 
#6 ·
Thanks Bugman, I read quite a bit on those and had hoped that was the issue (because it seemed like a cheap and simple fix) but I've checked the plug both cold, hot and while running with lights, mirrors, and rags and it is NOT leaking, almost seems like the leak is somewhere below that, I may need a smaller inspection mirror that's easier to maneuver, mine is a Kobalt LED lit mirror which is really nice but a tad larger for some of these spaces I'm trying to check out.
 
#8 ·
Update - here's a photo I just took, I inspected this while running and hot last night with no luck finding the source, wiped down the lines and bell housing when I turned it off last night, been sitting since and you can see in this photo the drop at the bottom of the bell housing and on what I think are transmission cooler lines - the oil on the lines I believe is dripping off the starter onto those lines where is collects until it's enough to drip off onto the ground.
 

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#10 · (Edited)
I learned after many years that my oil drain plug would often drip...
So now for each oil change I replace the drain plug washer
I buy a pack of them at the parts store, and use them for each oil change,,
Simple solution solved drips on the garage floor

Oh, and an easy way to change a leeky drain plug washer is to put a rag
Over your oil filler tube on top of the engine and take a shop vac
And push it down on the filler tube,,,
This creates a negative pressure in your crank case so you can actually
Remove the drain plug and replace the washer, with no oil leaking out,,
PS...needs 2 people to do it,,,
 
#12 ·
Thanks Graupp, unfortunately the leak I'm hunting for is not from the drain plug but somewhere higher and towards the back - I've heard of the shop vac trick, so you put a rag over the top of the filler tube and have someone hold the vac flush against it and that's enough suction to stop the oil from pouring out when you remove the drain plug?
 
#13 ·
Next place to look over there is the oil dipstick adapter. Oil from there will also get blown back behind the starter.
 
#16 ·
Thanks RT -the Dipstick is dry.

I pulled the starter off since I found that the oil was leaking from the starter area, down to the low center of the bellhousing. The photo attached here shows what I think is part of the EGR (is that right?) and you can see a wet spot in the "corner" of the block near what looks like an exhaust gasket - near what looks like an exhaust manifold that goes back up towards the turbo and has a foil wrap around that pipe, it's NOT the exhaust down pipe but it looks like there may be some oil leaking just above the gasket at the block, with the starter off I used my light and inspection mirror and still can't see where the oil is coming from - some of the bell housing bolts look a little oily and spraying brake cleaner on top of the bellhousing got a LOT of grime off, but I can't figure out where the oil is starting to leak from, anyone have any other ideas? Looking for a solution other than disassembling the EGR/turbo/exhaust from behind to look up the rear of the engine...leaking on the passenger side.

PS - second photo is after I hit that area with brake cleaner, that same "corner" still looks wet but it's the cleaner this time and not just the oil.
 

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#14 ·
Be aware, the oil pans on the 7.3 diesel is prone to rusting out, between the material they used, and the deep draw of the pan shape, makes it rust thru very easily, mine has apparently just enough grime on it, to have kept it safe since it was built, I personally would not like to have to pull the engine, to replace an oil pan, which by the way, very inexpensive compared to the labor to replace it, just passing it on! Bob
 
#18 ·
There is no EGR on the engine so scratch that off the list. That first gasket interface above the pan is the head gasket. It's not leaking oil there, but it may be a conduit or collection point for a leak higher up. Next level up is the valve cover gasket. They can leak and if they've ever been off before, they may not have been torqued down properly. That rear bolt is a pain to get to.


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#19 ·
There is no EGR on the engine so scratch that off the list. That first gasket interface above the pan is the head gasket. It's not leaking oil there, but it may be a conduit or collection point for a leak higher up. Next level up is the valve cover gasket. They can leak and if they've ever been off before, they may not have been torqued down properly. That rear bolt is a pain to get to.
Thanks RT, I pulled the valve cover off when I first bought it as the previous owner told me that a shop told him that was the major leak it had - turned out to be the HPOP o-ring but I inspected the valve cover gasket and re-torqued, that rear bolt IS a pain to get to, in fact someone left their socket on it previously - I'll double check that all the bolts are torqued but I'm pretty sure they are, I spent a long time going over both valve covers because I found several missing bolts after I cleaned all the grime off so when I replaced them all I torqued them to spec...or at least I thought I did. I'll double check.

I really don't think it's my rear main seal, but is there a way to specifically check that seal?
 
#20 ·
No specific technique, but if you put the dye in it and it is leaking there, you'll be able to see a distribution originating there and spinning outwards. The rear main on this engine is so overbuilt that the chance that it's leaking from there is minimal.
 
#23 ·
Checked this morning and had the same leak/drip as before, for some reason it took longer to run down last night than usual. I put the UV light on it and it didn't light up at all so I'm thinking I may just have to do it all again - clean it up, add more dye, run it and check again to find the source. I should be able to do this again this evening or may do it today if I get a chance and park it in the garage with the lights off to look for the leak. I'll provide an update once I run more dye through it.
 
#24 ·
In addition to the other things mentioned, there are plugs on the heads that can leak. Where the photo shows oil at starter mount is where RH cylinder head leaks will usually show. The leak will run in the head gasket gap and then down block. Same for a leak at intake fitting (intake manifold as it exists on these). The oil sent through intake from crankcase vent can puddle inside and leak and make a mess. Ditto for the orange connector hose for the intake. Turbo pedestal mount seals or exhaust damper servo need a look. All of these can run via the head gasket gap and not be too messy up top and then show up below. If oil in the valley up top drains it also is not always going to scatter left and right due to the way it runs down the rear main seal adapter plate that is behind flywheel.
7.3 rear main leaks usually cause little mess at block/pan joint but drip out of the hole on torque converter cover/dust shield out of the hole.
 
#26 ·
Update - I cleaned up everything again, put another bottle of dye in the oil, ran it more and finally was able to see the dye with the light - photos are attached. I could clearly see oil all around the oil pan "gasket" (which I know is an RTV type epoxy opposed to a formed rubber gasket) including around the rear main, oil on the cooler lines (passenger side 1/4" steel lines, and a drop running down the starter motor - there was also a drip at the bottom of the starter and bell housing, but both those drops didn't glow in the light.

Photos show:
-the leak under UV light on the cooler lines
-rear main/oil pan drain plug (I need a new washer, not worried about that leak),
-rear main
-valley behind the fuel bowl (just below the wire harness that's in the center of the photo plugged into the fuel bowl you can see the small puddle).

I still see no oil near the turbo or around the pedestal or any of the boots - I still cannot see where the oil is coming from that's leaking down onto the starter but it's not the galley plug, it looks like there may be oil on the rear outer "corner" just about the starter where one of the exhaust or turbo pipes runs along the block but I cannot see it without doing some disassembly. I did find that the small bit of oil in the valley is coming from under the HPOP or fuel bowl - I wasn't able to see the leak but reaching under it my hand came out with oil on it - anyone know what would be leaking on the underside of either the fuel bowl or HPOP?
 

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#27 ·
I was talking about oil using the headgasket to head gap as the conduit to carry oil. Not the gasket leaking. It looks like the blacklight and dye found it.
The sealant is high torque (cures harder than some of the older versions) RTV.
 
#28 ·
Thanks Jimmy - unfortunately even with the dye I cannot find the source of the leak, other than now knowing that I don't have an actual seal around the oil pan. I think I'm going to have to take the up pipe off off the exhaust manifold and turbo to see where exactly the oil is coming from that's behind that pipe, just above the starter. Any experience with this?
 
#29 ·
Cool looking pics, arent' they? So now instead of one oil leak, you're up to four or five. Medium velocity spatter behind the drain plug shows you what I was talking about with air currents moving stuff around. I forgot to mention how pervasive that dye is. Get a little on your finger when you screw the lid on the bottle, and the next thing you know, you've got fingerprints lighting up on every surface on the truck, house, garage, mailbox, keys, tools, - looks like a scene out of CSI...
 
#30 ·
Yeah, I was so lost last night as to where the source is for the main leak I'm chasing (near starter) I started to wonder if I should find a way to trap the oil but am going to continue the hunt to fix the leak(s)!

Near the rear main - I'm thinking that's just the oil pan gasket seeping out oil (since it's doing that all the way around the pan) opposed to an actual leak from the rear main, would you agree?

Any ideas what may be leaking underneath the fuel bowl? I read that most guys found it was the "non-serviceable plug" but I don't think that's it, going to try and dig in today with my mirror and confirm, hopefully will have a long break from work today...
 
#31 ·
It could be the plug, but it could be the mounting gasket. I find that once you identify the area it's coming from - it's better to just rebuild the whole device. So, if you see it coming from up front, just buy the whole re-seal kit for the HPOP and pull it once. If you order from dieselorings.com , you'll see a related products menu with the extras that you'll need to do everything. My 2 cents here - if you're pulling the HPOP, you're right at the fuel bowl so might as well rebuild that as well. DieselOrings: High Pressure Oil Pump reseal kit - 7.3L Powerstroke
 
#32 ·
Pull the covers off the HPOP lines where the dye showed up. That's where mine was leaking. CNC Fabrication has the full set of lines (3) for the HPOP rebuild, just like RT said, do it all when the HPOP and fuel bowl are out and be done with it.
 
#33 ·
Thanks both - I already did the o-rings on the HPOP lines to the heads, that was the main leak when I bought the truck. I agree though that just rebuilding all of it while I have it off is the way to go.

As for the leak around the oil pan gasket - any suggestions here short of loosening the bolts and re-sealing it - could I drop it like 1/8" and put more gasket maker in there to improve the seal without actually pulling the engine and totally dropping the oil pan?

As for the leak over the starter- I'm going to pull the starter off again now that I've got a UV visible leak there to see if it helps, I suspect I'm going to have to pull the up-pipe that runs from exhaust manifold to turbo off in order to see where it's actually coming from - any thoughts or suggestions here?
 
#35 ·
Yes, actually was planning on posting an update as I just made some progress.

Summary:

HPOP is no longer leaking and the valley is dry, seems to have been the non-serviceable plug. I definitely had a slow leak from a bad gasket on the oil pan bolts which has been partially fixed but not completely, I may still have to pull the downpipe and starter to see if I truly have a leak on the rear passenger head/block but it doesn't appear that I do so I'll have to determine that after I completely resolve the oil pan bolts since they may be causing what looks to be a leak near my starter because of the oil running backwards while driving.



Details:

I put in the UV dye and couldn't clearly see the source of the leak, still had a bit of oil in the valley and still had a run underneath - ultimately when feeling around the HPOP the only thing I could "feel" was the bottom side was wet, which other threads indicated it was PROBABLY but not DEFINITELY the "non-serviceable" plug.

I went to our local diesel shop and got a new HPOP gasket (the large metal gasket), o-ring for the plug, and IPR rebuild kit (as this was another potential source) - I ordered a new longer plug on Amazon, only because it was the cheapest and quickest shipping option (I bought THIS ONE).

I used both the Riff Raff Diesel and Diesel O-Rings instructions (free on each site) to pull the HPOP and replace the "non-serviceable" plug - when I pulled the old one it wasn't tight (didn't need heat or much force to break it loose and remove) and the o-ring was blown out, not completely but enough to leak. I followed the procedure and replaced with the new plug with longer threads and after reinstalling and running around quite a bit I have no more leak up top.

As for the leak around the oil pan - I loosened each bolt on the passenger side individually and put some black RTV on the bolts, re-tightened and then smeared a little extra around the bolt head - this helped but didn't completely stop what is now my main leak - from looking at it some more underneath with the UV light I think the main culprit (now that the HPOP isn't leaking) is a bad job of making the oil pan gasket, I need to retry what I already did as there were two bolts I didn't cover very well and they are still leaking just a bit, I'm also going to try and smear some RTV along the existing seam/gasket to ensure it's well sealed.

I THINK the oil leak from the oil pan bolts are what are ultimately causing the actual drip on my driveway, looks that the oil is dripping off the bolts and coincidentally falls right onto the cooler lines (transmission I think) that run on the passenger side and the oil then runs down to the lowest point and drips - I MAY still have a small leak somewhere above the starter but it's not clear at this point if I truly do or if the bit of oil that's in that area is actually running back from the oil pan also.
 
#37 ·
Look in the engine valley. Possible sources are oil smooge leaking out of the boots where they connect to the intake plenums. That accumulates and runs along the head/block joint to the rear. Another possibility is turbo pedestal O-rings, either at the turbo or the pedestal to block connection. Also the EBP piston seal can start leaking. There's a drain hole in the back passenger side of the valley that leads to the flywheel/flex plate area, which can sling oil around.
The previous advice of cleaning everything up and using fluorescent oil dye is what you should follow if you can't find it just by eyeballing everything.

Good luck and welcome to TheDieselStop :smile2:
 
#39 ·
Sorry for the delay, I couldn't get logged into the forum for some reason!

I ended up rebuilding the IPR, replacing the HPOP line o-rings, replacing the "non-serviceable" plug with the longer "serviceable" plug and JUST replaced the pedestal o-rings this past weekend, so I think the pedestal o-rings were the last culprit but I'll know for sure in a few days.
 
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