New to M35, getting started, where am I leaking?

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Karl kostman

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You have an interesting issue with this one replacing the pan gasket is a good place to start. Since its only leaking when underway and under a load my first thought is the Turbo oil lines, if you just sitting running the engine your building no pressure hence no leaks. The amount of oil you talking about is way to much for anything that would normally come out of the slobber tube and your oil seems to be getting much higher than the bottom of that tube anyway, but just to help isolate things I would attach an extension to that tube just to eliminate it. Now here is another thought, I do not know what that piece of material you found when you dropped the pan is but lots of very smart folks here who will likely know what it is. I dont know this but it could be something that is causing lots of blow by in the engine and that excess blow by could be coming from your slobber tube hence the extension on it. I am very interested to see what you found in the pan, it might be something and it might not, trust I am tuned in to see and good luck!
Karl
 

cattlerepairman

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So, your engine is "making oil". That is one thing to address, through changing some important o rings.
Diluted engine oil causes leaks.

The broken part...I was staring at it and it vaguely looks like a piece of oil pickup tube. You'd see that on the bottom end more or less straight away with the pan off. Others may have better ideas.

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cattlerepairman

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From the TM....this is was I was thinking for the curved tube. It has two 90 degree bends in it, one downwards and one to the right, the opening pointing to the passenger side.
Maybe the pipe came loose from the brackets and was whacked by the rotating crankshaft? The fractured part would be located towards the rear of the engine on the driver side. It is the oil scavenging tube for the rear sump. Did you, by any chance, find it in the rear sump?

Screenshot (13).png


The illustration is from TM9-2815-210-34-2-1, page 3-164
 

fleetmech

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So your engine is using/ losing lots of oil, but you drained over 7 gallons? If I have that correct, then you have some other problems than just the leak. "Making oil" is not an unheard of occurrence when internal fuel system seals go bad and start dumping large amounts of fuel into the crankcase. I have actually seen it so bad that large volumes of liquid will pour out of the crankcase breathers, carried by the vapor. How did the oil look/ feel when you drained it? Was it thin, shiny black... does the whole truck (or the oil) smell strongly of fuel when its running..? At this level it should be extremely obvious, so I'm not convinced this is it.

With that in mind... is your dipstick correct? Just throwing out the possibility that someone, somewhere could have installed an incorrect stick/ tube that is reading low, making it appear to you that you have to put in more oil then it needs, thereby overfilling the engine and causing leaks? Don't laugh... I've seen this too...

As for the piece that came out, what material is it? Plastic, soft metal, steel, rubber etc?

Heres one to throw at the wall... Is it possible an extremely incorrect "previous owner" mod or severely broken part is allowing boost from the manifold into the crankcase? I can't think of any real examples at the moment, but since the turbo only builds boost under load, IE driving not while free revving, that would explain why it can run in the driveway no problem, but goes to heck on the road...
 

clob mcstrunk

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The broken piece is solid round bar, not tubular. It is steel. Piece was found in bottom of front oil pan sump. No other metal shavings, particles, etc. on the magnet in the oil plug.

Dipstick appears stock/correct, but I'm open to info on how to confirm otherwise.

Oil pressure gauge has always jumped instantly to 60psi as soon as I flip the switch, before starting the truck. This is on my to-do list (possible bad grounding?) but thought I should include that info here to help with diagnosing.

Oil is very thin and pitch black. The exhaust from the truck smells very strongly, though what is considered normal is beyond me (the last diesel I owned was a '81 Mercedes ha!) It has smelled this way since I got the truck. Exhaust smoke is visible at idle, a light grey.

First 4 drives were just around the neighborhood for shakedown runs. Approximately 6 miles each. No leaks after these drives. Fifth drive was about 45 minutes, including extended 5th gear running. After this is when I noticed the leaking. Sixth drive, after degreasing and inspecting the undercarriage for leak source, was about 6 miles only to then find the same coverage/amount of leaking when finished.

I am tempted to reinstall the pan and filling with the correct amount of oil, buttoning everything up and firing her up to see if the leak persists. Other than the cost of oil/gasket/time is there advice against this?

I appreciate the input and help, please let me know what other details I can add or look for that might help further.
 

cattlerepairman

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No, do not do that without at the very least addressing the diesel fuel getting into the oil (hence the huge volume you drained). You need to
- bypass the FDC
- change the O-rings sealing the hydraulic head and shutoff
- check or eliminate the flame heater
- check/change booster pump seals

If you do not, you are risking just wasting 22 more quarts of good engine oil and having persistent leaks as the oil gets thinned out with diesel fuel.

As for the broken part...bummer, it really looked like a pipe on the pic. What else is solid and curved like that? Bearing cap?
 

clob mcstrunk

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FDC was already bypassed...?

I got the flame heater yanked today, will have to get plugs tomorrow for intake elbow.

3-seal kit for hydraulic head ordered; the viton rings? Big Mikes has this kit for the HH and then a kit for the booster pump with an o-ring, washer, snapring, and a collar/washer. Should I do both of these?
 
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M37M35

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Drained over 7 gallons of oil. This is after pissing at least a few pints out (if not more) during the last two drives. :shrugs:
From memory, the engine holds 5 gallons, so you're getting diesel in the oil. That could very well be why things are leaking.


It is solid, not a tube. When doing an initial inspection, I cant see where it might have broken off from. Can someone please tell me what it is and more importantly that isnt something that is going to make me want to cry?
Maybe a broken valve spring? It might be possable it could have made it's way into the pan from the valvetrain. It's easy enough to pull the valve covers and have a look.


The gasket that I removed was the single-piece style and did have a spot that looks like it could have been letting oil past, though not as big as I would have thought. The new gasket from Memphis Equipment is the mult-piece style, and one of the end sections is a different material than the other three. The thickness of all pieces is the same; should I be concerned? I've used RVT on plenty of applications in the past and have found conflicting reports of using it here. What about if RVT + paper gasket? Thoughts?
I would use #2 non-hardening Permatex on the gasket.
When I replaced a piston and head gaskets on mine, I didn't even use a pan gasket. I just used Ultra Black RTV.


So, your engine is "making oil". That is one thing to address, through changing some important o rings.
Diluted engine oil causes leaks.
This.


Oil is very thin and pitch black.
Yup, I can almost guarantee you're leaking diesel into the oil.


I am tempted to reinstall the pan and filling with the correct amount of oil, buttoning everything up and firing her up to see if the leak persists. Other than the cost of oil/gasket/time is there advice against this?
It won't hurt anything as long as you don't run it much with diluted oil. Will just cost you time and the oil.


- bypass the FDC
- change the O-rings sealing the hydraulic head and shutoff
- check or eliminate the flame heater
- check/change booster pump seals
You need to do these things. I had to do them on mine when it was making oil.

If you want to keep the flame heater, get 2 inline shutoff valves for the ice maker water line on a refrigerator and put them on the main and return fuel lines on the flame heater. You can keep them shut off unless you need the flame heater. Mine had this mod on it when I got it. One of these days I'm going to replace them with electric solenoid valves that activate with the flame heater switch so it's all automatic and keeps the flame heater from leaking.




FDC was already bypassed...?

I got the flame heater yanked today, will have to get plugs tomorrow for intake elbow.

3-seal kit for hydraulic head ordered; the viton rings? Big Mikes has this kit for the HH and then a kit for the booster pump with an o-ring, washer, snapring, and a collar/washer. Should I do both of these?
Yes.
The booster pump is a pain, but probably needs to be done. That's where mine was leaking from. Replace all the seals and you won't have to worry about them for a long time.

See above on flame heater. You can also leave the nozzle and sparkplug in place and just cap the lines.
 

Menaces Nemesis

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FWIW, when I took delivery of my truck it had 8+ gallons in the pan, but was NOT making oil (new HH o-rings, FDC bypassed, manifold heater disconnected, etc)...
Previous owner kept the truck parked on a steep driveway, pointed uphill, and I believe he just pulled the front pan plug, half-A$$ drained it, and dumped 5-1/2 gallons more on top of what was left in the pan. Because he didn't pull both plugs, and probably was too impatient to let it completely drain, it wasn't close to being drained, and then he way overfilled it by dumping 5-1/2 gallons more in.

AS FAR AS HAVING THE RIGHT DIPSTICK...
Click and expand the text in the post below to see the page from PS magazine (Compliments of Frank8003 from many moons ago)...
 
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clob mcstrunk

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Is it possible that there is a leak on the back/top of the differential that could be spraying that one area?

I know that doesn’t account for it making oil...booster pump seals and hydraulic head seals arrived today. Hoping to get time in the next few days to start on those.

Flame heater removed. Pan sealed with ultra black; maneuvering that thing solo with tacky RTV and not making a mess....

By the way, I was expecting the parts for the booster pump seal to be a bit more substantial for the price than what they turned out to be. Ouch.
 

gringeltaube

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.... Can someone please tell me what it is and more importantly that isnt something that is going to make me want to cry?
To me that looks like a piece of a valve spring. If it's hardened steel (a file doesn't grab) and little over 3/16" in diameter, then it is...

Now, for the second part of your question - if the first is confirmed then you may want to pull both covers and make sure all twelve springs are intact. I guess they are and that this is no reason to cry...:giggle:




Edit to add: just saw M37M35's response (hidden in post #30), so that makes two of us, same theory....
Maybe a broken valve spring? It might be possable it could have made it's way into the pan from the valvetrain. It's easy enough to pull the valve covers and have a look.
 
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gringeltaube

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Well, M37M35 and gringeltaube, yall were right....broken valve spring, third valve back from the front.

Hooray.
Aha... so I wasn't right when I said all 12 should be intact... 😕
I only based my assumption on what you said initially, the motor running "solid" - and the fact that a cylinder with a shattered valve spring would make an engine run rough and under-powered, at least...
 

clob mcstrunk

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To be clear, this is my first MV, first M35a2. I'd never driven one before buying so my understanding of how it was running was less than educated. Now that I know this, the difficult start up makes a bit more sense.

I have done a fair bit of TM searching for a lead on the process from here, but if there is something in there specifically that I should focus on, I'm all ears (eyes.)

What damage am I likely to find when I pull the head? How much damage might I have done by driving it like this. Engine has not been opened in quite some time, so there's no telling how long this has been broken.

Current thought is to pull the head, replace spring (or all springs if it would be advisable), and button everything back up. I've come across a variety of reports about what, if anything, to have done at the machine shop, but if I dont need to go that far, then I'd love not to have that added cost.
 

gringeltaube

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I'd replace the spring and eventually do a compression test first, before going through all the work of pulling the head.
(No big deal to replace a spring, with the piston at TDC. It's a one-man job and can be done with no special tools.)

Yes, the valve may have touched the piston occasionally, but if you are lucky it didn't get bent and still seals well.
 
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