Black Cannister in Rear Engine Compartment

[JC2]

In the rear engine compartment of our 2010 Newmar Dutch Aire is a large black cannister that I believe contains several gal of hydraulic fluid-as stated on a label-AW 46. Several months ago, I notice a small sauce plate size oil leak on the ground under this cannister. I wiped this up as it did not appear to be leaker further. Several days ago, I took our MH to a Cummins service center for pm on the big engine(425 Cummins) and the 10kw generator. I did not think to have them check for a leak as it had not occurred again for several months. When I picked the mh up and drove back to our winter residence, about 4-5 miles, I noticed that the leak had started again but heavier. After shutting off the engine, the leak stopped and did not start again approx. 15 min later when I retarted and fast idled it for about 5-10 minutes. I checked the dip stick in the black cannister several times and it showed fluid overfilled up to the bottom cap of the dipstick. I also checked the same about 7-10 days before taking it in for service and the fluid level was way high at that time also. I have since suctioned out about a small juice glass of fluid and the level is down slightly below full.
If overfilled, would this cause the fluid to be purge somewhere and drip like this?
Thoughts anyone?????

[Old Scout]

Perhaps....and depending on where you Cummins engine or Allison tranny dip-sticks are located, an overfill situation with them could cause a similar overflow out these dip sticks too.....hydraulic fluid/tranny fluid is reddish in color, engine oil is black....if hydraulic fluid came out the black canister, seems like you would see fluid running down the side of the canister--not really another place for overfilled hydraulic fluid to leak out....

[Tigerfan1]

Originally Posted by JC2

In the rear engine compartment of our 2010 Newmar Dutch Aire is a large black cannister that I believe contains several gal of hydraulic fluid-as stated on a label-AW 46. Several months ago, I notice a small sauce plate size oil leak on the ground under this cannister. I wiped this up as it did not appear to be leaker further. Several days ago, I took our MH to a Cummins service center for pm on the big engine(425 Cummins) and the 10kw generator. I did not think to have them check for a leak as it had not occurred again for several months. When I picked the mh up and drove back to our winter residence, about 4-5 miles, I noticed that the leak had started again but heavier. After shutting off the engine, the leak stopped and did not start again approx. 15 min later when I retarted and fast idled it for about 5-10 minutes. I checked the dip stick in the black cannister several times and it showed fluid overfilled up to the bottom cap of the dipstick. I also checked the same about 7-10 days before taking it in for service and the fluid level was way high at that time also. I have since suctioned out about a small juice glass of fluid and the level is down slightly below full.
If overfilled, would this cause the fluid to be purge somewhere and drip like this?
Thoughts anyone?????

I had a leak on my last coach. Mine was leaking from the fitting on the bottom of the tank. There is a gasket there on the inside of the tank that may need to be replaced. Unfortunately to do that you have to drain the tank.

[10 fan]

One of those hoses should go to a large hydraulic filter (probably down). Check there also for leaks. I replaced the drain plug on the bottom of the reservoir with a easy oil drain plug. Have to drain the reservoir to change the filter so this will make it alot easier.

[JC2]

Thanks everyone for replying. Tomorrow I intend to :

1. Do the search and suggestions given so far in the responses.

2. Start the big engine and run it at high idle for about 30 minutes and see if the leak will start again. Don't like to start the engine and do this but high idle(1100-1300 rpm) should hurt it.

3. If it doesn't leak then will drive it 5 miles or so which was the distance one way to where I had the maintenance done last Wednesday.

4. After the big shutdown from the virus and slowness of cg's to open, we are scheduled to leave down here in south Texas and head back up to just north of KC, Mo on Mon June 8 so won't feel comfortable until I find what the problem(?) is/might be and get it fixed.

[JC2]

Another question I should have asked in my original post is what uses the hydraulic fluid from the black cannister?

[10 fan]

Power steering and a hydraulic fan, on mine.

[10 fan]

I should of added that my reservoir canister has a power steering filter in side on the bottom along with the external hydraulic filter.

[Capt. Bill]

JC2- on my previous coach- 2005 MADP on a Spartan chassis, I had the same arrangement you have. This reservoir holds the hydraulic fluid for the power steering & radiator fan drive. You have to drain the canister & replace the Nelson internal oil filter periodically per the service interval. This involves taking off the lid retaining ring & gasket- I always put on a new gasket to ensure it didn't leak.
Be sure to tighten the drain plug & entrance & exit lines when you perform this service.

Happy Trails

[JC2]

Success, I hope.

Yesterday, using the suggestions provided by those on this forum along with process of elimination steps, and a second set of eyes from some folks and our winter park,I believe the elusive leak has been solved.
YESTERDAY(Sat):
1. All fittings, filters connected to the hydraulic oil cannister in the engine compartment were checked and found to be tight.
2. The big o cummins motor was started and run for about 40 minutes @ 1300rpm and reached about 170-75 degrees.
3. No joy as I noticed about 8-10 "reddish" colored oily feeling on the ground in the same general area as before. Crap!!!!!
4. I had siphoned almost 14oz out of the obvious overfill from the hydraulic fluid cannister before starting the engine so was certain it wasn't that. The fluid also appeared "brownish" in color anyway.
5. ATF trans fluid? Hope not and it wasn't.
(Before starting step #6, we waited an hour or so for the engine to cool)
6. When we dug behind a jumble of wires around the bottom of the hydraulic fluid cannister, a black rubber tube was in the jumble and was an overflow tube coming from the antifreeze tank. It was moist on the bottom opening and just above where a lot of "reddish" liquid has dropped.
7. I then carefully loosened the radiator cap and after the gurgling stopped, I looked in the fill tube and the "reddish" colored antifreeze with the same feel as the drips on the ground, was no more than 1 inch from the top of the fill tube. Maybe a little overfilled. Let it cool over night.
8. Checked this am and the level has dropped maybe an inch. After siphoning off about 3/4 gal, the level seems to be where it should be.
9. Thanks everyone for ur help. It makes owning an rv more tolerable when Murphy's Law pops up.