Leaking (?) hydraulic oil

[Johnontheroad]

Did my usual walk around before leaving Durango, CO and all was well. Did note that the hydraulic oil looked full, but no leakages or notable issues. But when I did a walk around on top of Wolf Creek Pass I noticed a rapidly expanding oil slick. On checking, it seemed to be hydraulic oil leaking out of the fill cap. But the oil level was totally full.

Since we only had 20 miles to go I continued to our next stop. Checked again, and no more leakage, and the oil level was still totally full. I had the coach fully serviced in March, so I’m wondering if maybe the hydraulic oil was overfilled and the expansion of high altitude caused the leakage?

Don’t think this is a cause for concern but in my mind any anomaly in coach operation needs research. Any thoughts?
Attachment 1

[garysfb]

I've been up to 9000 ft and never experienced an overflow. Certainly worth a call to Entegra.

[brobox]

I lived in CO for 20 years and have run every pass in the state with a Winnebago or something similar. I have never experienced fluid expansion due to altitude.

[HarleySG]

Nope, currently live in CO and have never seen that. We are currently in Pagosa at Wolf Creek.


Hope you figure it out and report back if it continues.

Cheers

[Gasman 2]

I’m leaning toward it being over filled, and when it came to operating temp it over flowed.
One thing I would check is the oil level of the engine, to make sure it’s not coming from there.
Richard

[LWBAZ]

Also possible the cap on the tank wasn't tight and the steep hills you climbed tilted the tank enough to allow some leakage?

[Johnontheroad]

I’m aware the fluid itself wouldn’t expand enough, but was wondering if their may be an air pocket or something that expanded, pushing out the oil. And it wasn’t engine oil, but thanks for the suggestion. I will check cap sealing, oil levels etc. again this morning when the engine has fully cooled down.

BTW, the leveling system is separate from the engine with its own fluid reservoir. Slides are all mechanical. Brakes are air. So the only use for engine mounted hydraulics that I can think of is the engine cooling fan motor. What am I missing here?

[RayandWendy]

I'm not positive but I think it's also for the power steering.

Later...
Ray

[JJT]

Might want to check the hydraulic fluid level for your leveling jacks. A close friend of ours sprung a pin hole leak in the line that supplies the rear jacks and left a trail of hydraulic fluid behind the coach that looked exactly like yours. They ended up having to call emergency service to ratchet strap their levelers in the up position, as they eventually could not get the jacks to stay up.

[Johnontheroad]

Leveling jacks still work fine and I can see a trail of oil from the reservoir cap down. So that is the likely location, but I will check again just to make sure. Power steering seems logical. Now that you’ve said that I shudder to think what may have happened on my way down from Wolf Creek pass if my steering would have locked up…

I will have to research this much more diligently than I have so far. Thanks for the reply.

[Gasman 2]

Just remember the hydraulic pump for cooling fan and PS drives from the accessory drive on the Cummins. So the two oils are in close proximity of each other. I think it would be remote if the source of the extra oil came from here.
But if there were a seal failure on the pump could that happen, don’t know. I do know there is a suction side and pressure side of that pump.
Look at all possibilities, strange things can happen on these beast.
Enjoy your trip, I still think it was over filled perhaps they didn’t pay attention to the two marks on the dip stick.

Richard

[Johnontheroad]

OP update: last night I cleaned everything and checked this morning, no sign of leakage anywhere. But the hydraulic oil level was now below the ADD level so I better top that off. Then I’ll run it and check everything again.

After that, I will check frequently to make sure the oil level stays up. Still would like to know why it expelled the oil, I’ve been over this pass twice with this motor home and many more times in other MHs equipped with Cummins engines and never seen this before.

[brobox]

Is the ADD mark when Hot or Cold?

[Gasman 2]

Originally Posted by brobox

Is the ADD mark when Hot or Cold?

Chuck,
The marks are marked as cold level and hot level.

Richard