Cat 345 B Leaking hydraulic fluid in engine oil

Spencer-auto · Oct 21, 2013

Cat 345 B 1997 Leaking hydraulic fluid in engine oil? Have had a mechanic here for 2 weeks trying to fix problem with no luck.
Changed the pump for hydraulic fan twice... (Brand new)
This cat has a 70r Labounty shear on.it
We are at a loss , Any ideas ?

trackdoc · Oct 21, 2013

Thats a strange one, the fan pump seemed like the correct repair.
You sure it's hydraulic oil ?
Is the bell housing dry?
The pilot pump is inside the bell housing, and I guess it could gain oil from there through the rear crank seal.

Spencer-auto · Oct 21, 2013

yes we had that analyzed it is Hyd.fluid. Bell housing was dry But took it off and replaced the pump any way., And the rear main seal was also replaced

Niall · Oct 21, 2013

hyd fluid in engine oil?(tricky one, but you do hear of unknowing maintenance guys)
or
engine oil in hyd fluid?(from rear main into pump but the bellhousing is dry....stumped)

any chance that hyd oil cooler/"radiator" might be playing with you?
sorry, i don't know that piece just tossing ideas

Spencer-auto · Oct 21, 2013

These Guys are from The Caterpillar Shop. Not cheap mechanics. So I would have assumed they would have known how to fix this LOl There not supposed to be shade tree mechanics . The hyd. Fluid is getting in the engine oil.
Not sure how its getting in there. Thinking these guys are stumped to. Trying to figure this out Before This bill is astronomical .. This has a Shear on the stick. Radiator?

stondad · Oct 21, 2013

Sorry for sticking my nose in but you never know.

Could there be a stacked oil-to-water heat exchanger where the hydraulic/steering/fan/brake oil cooler is up against the engine oil cooler and leaking across without any getting into the water?

Often a bypass valve is run in parallel with the cooler to limit the pressure in a number of circumstances and if faulty, could cause a crack or even an internal Oring failure.

Hope this somehow helps.

Spencer-auto · Oct 22, 2013

Stondad, There is no heat exchanger. Thanks for the suggestions.

Niall · Oct 22, 2013

been thinking and durn... yea i was thinking there could be a remote engine oil cooler fiddling with the hyd oil cooler..... now i have had the crank/main seals inside spring pop off during installation but you replaced the pump as well so that seals new.... mmmmmm now how bad is it: is it raising your engine oil level? is it just tested to have hydraulic fluid in it, how much? a "drain and fill" oil change could leave residue I suppose could get picked up by testing equipment. I'd say try an engine flush oil change, monitor the level/color, and trust that as long as it doesn't turn clear with black specs you should be well lubricated, i just hate dirt and grit

Niall · Oct 22, 2013

granted thats a nice piece of equipment and this might be a little shade tree

Spencer-auto · Oct 22, 2013

yep changed the oil every time they change a part.. Tested it for fuel and hyd fluid. came back just hdy fluid in oil. Gains 1 to 2 gallons of hyd fluid in about 15 minutes of using the shear.. I have over 850 dollars in oil changes as of now. changed oil 4 times so far. This is getting real expensive just in new oil.

Niall · Oct 22, 2013

wow... that much gain sounds like the pump... i'm at a loss hopefully another gent has an idea

02Dmax · Oct 22, 2013

Man that's a lot of gain. Theres not by chance another aux pump mounted on the front cover of the engine is there? My only idea.

Sent from my SPH-L710 using Tapatalk 2

Spencer-auto · Oct 22, 2013

No Aux pump on the front of motor. Keep the suggestions coming.. Maybe we can figure it out together. Tomorrow they will be here with a relief check valve for the hyd tank? we will see if this works

02Dmax · Oct 22, 2013

Hmmm. Maybe they think its building to much pressure in the tank. Theres an air line that goes from the engine to the hyd tank, basically it puts turbo boost into the tank to pressurize the hyd tank. Theres no place I know of that the hyd fluid could enter the crankcase through that hose but you might follow that line and make sure. I think it hooks into the intake manifold somewhere but haven't been around one of those machines for awhile.

Sent from my SPH-L710 using Tapatalk 2

Spencer-auto · Oct 22, 2013

checked that line its 12lbs that is what they said it should be . Good thinking ..

stondad · Oct 22, 2013

Oh man.

You threw me big time with this in the scraper section, so I musta sounded pretty silly talking about brakes/steering etc.

Your clue is that it happens when the shear is operated.
Was the shear only just fitted? Or has the fault only just occured after previously operating ok?
Has the shear been piped up to an aux spool in the control valve, or what used to be the bucket spool, or is there a seperate, electric control valve fitted?

I would love to see the hydraulic circuit for the machine.

Cheers. M.

stondad · Oct 22, 2013

Ok. I should have read all the posts more carefully.

I just googled Labounty, so now have an idea of what you have.

Does your rotate motor have a case-drain line?

FMD · Oct 23, 2013

Spencer-auto said:
Cat 345 B 1997 Leaking hydraulic fluid in engine oil? Have had a mechanic here for 2 weeks trying to fix problem with no luck.
Changed the pump for hydraulic fan twice... (Brand new)
This cat has a 70r Labounty shear on.it
We are at a loss , Any ideas ?

Does the shear have a rotator on it. If so, it could be the rotator.................

Spencer-auto · Oct 23, 2013

Yes it rotates, And this shear has been on there for over 5 yrs. Model 70 r . Rotate

stondad · Oct 23, 2013

Does the motor for the rotator have a case drain line ?

Cat 345 B Leaking hydraulic fluid in engine oil

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