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OT- Kubota diesel leak at oil pan gasket.... bolt torque question

Milacron

Super Moderator
Joined
Dec 15, 2000
Location
SC, USA
Officially is a Universal 35 hp marine diesel in a sailboat but the block is Kubota. Pretty bad oil leak at the pan gasket been going on for many months (absorbent mats down of course), just now got around to finding the source... drops coming from gasket about mid way on one side. No way in hell to get a torque wrench in such a tight space or a standard 3/8 socket wrench for that matter, so used a small box wrench (10mm) and tightened all the bolts on that side as best I could.. None were loose and suspect they were already at spec torque but I managed to turn them another 50 degrees.

This helped...alot...but still a small drop leaking every 50 seconds. So the question is, given the PITA factor of getting into that cramped space, should I try with longer wrench to get them even tighter still or is any further leak reduction probably not going to happen ?

(And yeah I know, ultimately it really needs a new gasket....but replacing the gasket would be a major PITA given the fact that the pan could be lowered but not removed...probably would require raising the engine a few inches. Also the boat is for sale, which is the only inspiration to do what I've done ! :leaving: )
 
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michiganbuck

Diamond
Joined
Jun 28, 2012
Location
Mt Clemens, Michigan 48035
One can go to the grocery store and pish the weight scale with one finger, two, and three. You may find 7 pounds. 14 lb and 30lb then compute to the length of your wrench.
It is crude but it works in a pinch with nothing other to be the gauge.
 

Garwood

Diamond
Joined
Oct 10, 2009
Location
Oregon

I don't know what's in this shit, but it's what Ford used to glue the oil pans on the 7.3 Powerstroke without a gasket.

I've seen a friend use this stuff on pressurized oil leaks on large engines by cleaning very well and smearing it over the leak then letting it dry overnight.

I have used it to seal the front of the head to the timing cover on a D8N Cat dozer when a square ring rubber coolant seal blew out. That fix was years ago and still working everyday.

Clean well, apply liberally, let it dry. The shit can do miracles. Until the next guy has to take it apart of coarse.
 

eKretz

Diamond; Mod Squad
Joined
Mar 27, 2005
Location
Northwest Indiana, USA
Yep, gonna have to get it off of there. Turning it further is unlikely to do much more, and risks stripping the hole or snapping the bolt. Getting everything completely clean and using silicone RTV for a gasket is about as good as it gets. Probably just sell it like it is. If they notice it just say you never got around to fixing it. Smearing sealant on the outside is unlikely to do anything.
 

Milacron

Super Moderator
Joined
Dec 15, 2000
Location
SC, USA
Yep, gonna have to get it off of there. Turning it further is unlikely to do much more, and risks stripping the hole or snapping the bolt. Getting everything completely clean and using silicone RTV for a gasket is about as good as it gets. Probably just sell it like it is. If they notice it just say you never got around to fixing it. Smearing sealant on the outside is unlikely to do anything.
While I personally would be fine with it as is for years, if the boat surveyor sees even one drop (which he would on the absorbent mat) after sea trial he will make note of it and the buyer will fret thinking it could be something more serious. I would just hire someone to change the gasket but nearly impossible to get marine diesel guys around here in less than 3 months out. The "good one" told me late fall... which of course really means, middle winter... LOL
 

eKretz

Diamond; Mod Squad
Joined
Mar 27, 2005
Location
Northwest Indiana, USA
I use silicone RTV on the bolt threads too. Ultra Blue works really well.

Not sure what else could be done to stop it leaking short of dropping the pan if the tightening didn't do the trick. If it's a drop every 50 seconds it's not likely coming from the fastener threads, anyway.
 

Garwood

Diamond
Joined
Oct 10, 2009
Location
Oregon
Smearing sealant on the outside is unlikely to do anything.

I know it works. I have seen it done more than a few times. That stuff I linked to will do it.

First time I saw it used was on a 1970's Peterbilt log truck with a Big Cam Cummins. There is a seal between the transmission adapter and the block at the rear that seals the main oil galley. This truck was spewing oil out of that seal at the rate of a coffee can every 5 minutes idling in the parking lot. 2 cans of brake clean, some wire brushing, a wipe down with wax and grease remover and that Ford sealant carefully troweled over the entire seam stopped the leak. That was years ago and that truck is still out there hauling logs.

This isn't the right way to do it, but it does work if you prep it to perfection, apply carefully and let it cure overnight.
 

mnl

Cast Iron
Joined
Sep 7, 2007
Location
Maryland near DC
Look at the risk reward. If you try and tighten it it might work, or it might not. You could also strip/break a bolt. In two out of three scenarios you will be dropping the pan. But in one of those you will be in a much worse world of hurt. You might have to pull the engine out of that nasty little space.
 

Robert R

Hot Rolled
Joined
Aug 27, 2005
Location
Raymond , CA
given the fact that the pan could be lowered but not removed...probably would require raising the engine a few inches.

Lower the oil pan two inches. Wipe clean the engine block and apply a bead of sealant to the block. Push the gasket up into the sealant. Then wipe clean the oil pan and apply a bead of sealant. The pan is then pushed up and the bolts torqued. The rubber gasket has become brittle and is no longer making a effective seal. Applying sealant to both sides of the gasket will solve the problem

The hazard with this approach is that the rubber (or cork) gasket may break apart when the pan is lowered.
 

DrHook

Hot Rolled
Joined
Oct 8, 2013
Location
Pierre
I don't know about the sealer Garwood is using, but I DO know that Permatex "Right Stuff" (black) will seal up leaks like that. I discovered it on You Tube when my '08 Harley developed a leak around the alternator wires, which my dealer said was going to be a $800 fix... That was 5 or 6 years ago. I have since used it with the same results on other leaks including a couple aircraft. Clean thoroughly with brake cleaner, brushes, compressed air, whatever it takes until no oil residue shows on a paper towel. Press into gaps and coat the outside with a decent layer, and allow it to sit for 24 hrs. Works on Harley Davidson, Continental, Lycoming, Chevy, Dodge, Ford, and counting...:D
 

Scottl

Diamond
Joined
Nov 3, 2013
Location
Eastern Massachusetts, USA
Sometimes the old stamped rocker covers used to seep oil even with new gaskets because a previous owner had overtorqued the bolts so the quick fix was to use cut down Corvair valve cover shims to distribute the clamping pressure.

Perhaps something like that might help if you can get your fingers in there.

Also, Thextonite used to make a gas tank sealer stick that worked well on oil leaks if dipped in gasoline before rubbing on the seam at a leak.
 

boslab

Titanium
Joined
Jan 6, 2007
Location
wales.uk
I’ve worked on the mitsibushi boat engine, same essentially, one a clone of the other, the gasket was good old cork, paint with red gasket compound ( stag over here, stinky red muck) those screws want a bit too but just tightening where the leak is will bend the pan imho, possibly leading to a catastrophic failure along the way, you know the bullet must be bitten sooner or later
Unfortunately, loosing power on a boat has got to be the last thing you need, ( same engine in the digger from memory, also bloody impossible to drop the pan)
Machines, sent to annoy us!
Mark
 

michiganbuck

Diamond
Joined
Jun 28, 2012
Location
Mt Clemens, Michigan 48035
QT (also bloody impossible to drop the pan)
I'm thinking if you can reach the pan screws you might pull them, add some treads sealer, and put them back with an elongated washer...and draw them up to spec.
 








 
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