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 ?
Check for a flooded flywheel housing. If there is no plug at the bottom pull the starter and check. Later Bob
Bob, yes its dry.. Looked at that. Put a new pilot pump in and new rear main seal
The hydraulic tank has pressure in it, Can it push it in to the motor oil? Is there to much pressure you think in the tank and blowing it threw the fan motor?
Have seen this happen,two hoses or a hose and steel tube rub and wear through enough to transfer oil but not leak externally. Check the remote engine oil filter hoses first. How did this start, suddenly or was something repaired first? Later Bob
Has the seal on the fan pump ever been damaged or out of place when you have removed/ replaced it ?
Had not checked the oil in a week and when I went to check it, it was a gallon over full. Nothing had been repaired before that. Yes have changed the fan pump 3 times and the seal Brand new cat parts.. They are thinking now Could be a Check valve between the tank and hydraulic fan motor pump.. They will be back tomorrow and we will see how it goes . They are going to change the check valve. Keep the ideas coming in case this doesn't fix it
Have you heard of a check valve not working and forcing the fluid back in to the engine?
Nope, there is a make up valve on the fan motor, not sure how this could be part of the problem though. In that system there is the pump, a relief valve to set the pressure, the make up valve which keeps the oil on the inlet side of the motor at a constant pressure and the motor. What is your serial number prefix ?
I think the check valve they are talking about is on the motor outlet to allow the fan to run down, when the flow of oil stops. Some fan motors have them in the housing. Try prevent exh oil pressure from building if the fan control slows it down. Oil just cycles around inside the motor. Later Bob
serial # Ags00592
Well, if it gains that much in such a short amount of time and none knows where it is coming from I'd pull the fan pump from then engine and do a short run without it installed in the engine but still hooked up hydraulically while using the shear and see if it stops the transfer of fluid. And at the same time keep a close look on the axle seal on the fan pump if it leaks. Have the case drain pressure on the fan pump been monitored?
less than 10 pounds idling cold.. What you sugg is a good idea . They are coming today to install the pressure relief valve or check valve That goes back to the fan motor.
PEr Eriksson We Did what you said did a short run with the turbo Pressure not hooked up (half Hour With shear running and cutting)And its better Not a gallon over full about only a couple quarts. So still not fixed think the pump went bad again because of the shut off valve.. So who knows all along could have been the valve ruining the new pumps.. Job not finished yet
Fixed , Wasn't hyd fluid , It was diesel fuel all along. #5 injector was leaking changed all the o rings and Changed the oil for the (5th time) When they sent in the oil to be analyzed it came back as hydraulic 2 times.. This was bad diagnostics on some ones part Thanks for all of your suggestions ,,, Havent got the bill yet .. But we are happy its fixed
Always good to hear a success story. I guess you'll be changing oil analysis labs soon..? It's unforgivable to confuse a drop in viscosity of engine oil as being caused by hyd oil when infact it's fuel. FFS that's basic oil analysis protocol...!!
Didn't anyone smell the fuel in the oil, even with our dogpiss they sell as diesel you can feel the smell.
couldn't smell it That is why they sent it in to the lab to the professionals.. crazy a month of chasing a hydra. leak to find out it was diesel. Guess this is why we hired a professionals to do the job.. LOl
Not uncommon, I got involved with a 3408 that had fuel dilution one time. Everything but the injection pump had been changed , that was all I had to do then start it up. Needed to use the fuel ratio control from the old pump. When I took it off there was a scum like antifreeze and oil mixed on it. Got a clean pail and cracked the oil pan drain, a gallon of coolant came out before any oil. There was a steady stream coming down from the front liner. That was about 6 incorrect oil samples. The lab swore it couldn't happen. Later Bob
Oil Analysis Labs do a lot of swearing - until the day when you prove them wrong ......!!
At a last resort, witch prob should have been a first . they put dye in the fuel took off the valve covers and There it was diesel squirting all over.. Prob should have done this first would have been fixed on the first day, Not a month later
Well I guess like they say hindsight is 20/20 and always easier to judge a job when you stand back and look at all the clues after the fact. Yes it does seem like it would have been an obvious problem but hey these things happen - every mechanic at some point has gone down the wrong road especially when they are being told - It's hydraulic oil !!!!! - Thanks for the update on what you found cause for me things like this are a great tool to learn from and reminder- keep your eyes and ears open and keep a broad view when t/s strange problems. Whether its an oil lab, the owner or operator they can all lead you astray (non-intensionally) so keep an open mind.