Oil leak in CAT ?

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Oil leak in CAT ?

July 21, 2016, 01:25:06 pm

Went to check fluids after a trip up north. Found what appears to be engine oil on the rear frame member. All fluids seem fine, though a slight amount of engine oil is down (1/16") Looked up and down, but can't see the point-of-leak. Could that be hydraulic fluid from the pump? I'll have to get my four-volume service manuals out, as I have no clue where to check the fluid. Any clues?

Re: Oil leak in CAT ?

Reply #1 – July 21, 2016, 01:54:48 pm

Mike,

Hard to tell the source as a couple of drops of oil can really spread out.

With a white paper towel, wipe some of it up. You will have to take this with a grain of salt because residual dirt will "color" the results:

If the oil is black, it is from the engine-- again dirt on the cross member can "taint" your color readings.

If clear, it is hydraulic.

Same oil in both: Delo 400 15-40.

You can also look behind the pulley for the hydraulic pump to see if the main shaft seal is leaking.

Brett

Re: Oil leak in CAT ?

Reply #2 – July 21, 2016, 02:11:04 pm

Quote from: wolfe10 – July 21, 2016, 01:54:48 pm

You can also look behind the pulley for the hydraulic pump to see if the main shaft seal is leaking.

I have a sneaking feeling it's the shaft seal. Where do I find the filler, so I can top her off and get up to Flagstaff for service?

Re: Oil leak in CAT ?

Reply #3 – July 21, 2016, 02:12:25 pm

The big black tank is the reservoir at back of engine room. Again, Delo 400 15-40 is the correct fluid.

Re: Oil leak in CAT ?

Reply #4 – July 21, 2016, 02:17:14 pm

More information:

New Hydraulic fan pump and fan motor 8/1/04 (see Barnes #), new filter & fluid. Change oil & filter 6/1/07. @ gov RPM cold: max 2200 PSI. Summer: Mountains 1,500, Other 1,000 PSI. Winter: 350 PSI. 0 turns=1500. - 1/2 turn= 1325. -1 turn= 900. -1 1/8 turn=700. -1 ¼ turn= 500. 4/6/12 -1/2 = 1325.

Barnes Hydraulics/Haldex 800 572-7867. 815 398-4400. Pump: 1800465. 09JAN2002 pump build date

Re: Oil leak in CAT ?

Reply #5 – July 21, 2016, 02:38:44 pm

Quote from: mike leary – July 21, 2016, 02:11:04 pm

I have a sneaking feeling it's the shaft seal. Where do I find the filler, so I can top her off and get up to Flagstaff for service?

I would probably not be in a big rush to fix the small oil loss. As Brett said. Clean it up and see if it repeats?

The older cat mechanics thought that the yellow epoxy paint cat used held in the leaks....

Re: Oil leak in CAT ?

Reply #6 – July 21, 2016, 03:42:55 pm

Quote from: Caflashbob – July 21, 2016, 02:38:44 pm

I would probably not be in a big rush to fix the small oil loss. As Brett said. Clean it up and see if it repeats?

The older cat mechanics thought that the yellow epoxy paint cat used held in the leaks....

Yup, not to 'jack my own thread, but another thing would-be buyers would want to check out with the "paperwork". We joke about "Coach Bucks", but a little deal like mine could eat one.

Re: Oil leak in CAT ?

Reply #7 – July 21, 2016, 04:09:00 pm

What I thought was an oil leak was actually a fuel leak at the intake manifold. Local garage repaired it for a small fee. It was dripping below the engine so I too thought it was an oil leak.

Re: Oil leak in CAT ?

Reply #8 – July 21, 2016, 04:09:25 pm

Mike,

Let us know what you find. There ARE shops that work on the pumps. Do not assume you have to replace with new unless the pump body and/or shaft truly is worn and not just a seal.

Re: Oil leak in CAT ?

Reply #9 – July 21, 2016, 05:16:41 pm

[quote author=wolfe10 link=msg=239875 date=14 Let us know what you find. There ARE shops that work on the pumps. Do not assume you have to replace with new unless the pump body and/or shaft truly is worn and not just a seal.[/quote]
Yup, which is nice to have these "quandary" situations sort of figured out, before hand. Being full timers makes for a not-so-much fun stay unless all the options are covered, and, most importantly, are (ALL) parts available, now?

Re: Oil leak in CAT ?

Reply #10 – July 21, 2016, 06:58:37 pm

To avoid further mess you could attach a piece of pig mat or another absorbent pad to that cross member

Re: Oil leak in CAT ?

Reply #11 – July 23, 2016, 12:30:11 pm

As per suggestions, I checked the color of the oil on the frame member, BLACK. But we just got back from a long trip and it could have been road oil color mixed-in, as well. The reservoir ? in pic one right next to the air dryer (like to know what THAT is) shows dark oil, full. Pic two, the large one on the left rear, shows pretty clear oil, down a tad, but not serious. I'm going to make up a piece of cardboard and stick it under the pump and run the coach to see if I can spot the leak. Dinking around with a flashlight showed me no point-of-exit, however, as a ex- home-restoration contractor, I know fluids can come from a place not even close to where the leak surfaced!

Re: Oil leak in CAT ?

Reply #12 – July 23, 2016, 01:27:26 pm

Mike,

Both are hydraulic reservoirs.

The smaller one on the passenger's side near the air dryer is for the power steering.

The larger one on the driver's side is for the hydraulic fan (driven by the pump that has the separate belt on the passenger's side of the engine.

Being hydraulic systems, if either has anything but clean oil (Delo 400 15-40) it is way past time to change the filter and fluid.

But, I don't see either reservoir contributing to the oil lead on the front engine support, since they are both well away from that area.

Re: Oil leak in CAT ?

Reply #13 – July 23, 2016, 01:50:31 pm

Quote from: wolfe10 – July 23, 2016, 01:27:26 pm

Being hydraulic systems, if either has anything but clean oil (Delo 400 15-40) it is way past time to change the filter and fluid

Thanks, Brett, as per usual great advice. Mite have to go back and modify my thread about what to look for when buying a used coach.

Re: Oil leak in CAT ?

Reply #14 – July 23, 2016, 02:31:46 pm

Heck, Mike, it takes me several hours to do a coach mechanical inspection and I have been doing them for a long time.

These things ARE complex-- lots to keep up with.

Re: Oil leak in CAT ?

Reply #15 – July 23, 2016, 03:42:46 pm

Everybody knows Cats don't leak! : )

Re: Oil leak in CAT ?

Reply #16 – July 23, 2016, 05:22:17 pm

No, they purr😀

Re: Oil leak in CAT ?

Reply #17 – July 27, 2016, 02:31:25 pm

Cleaned the frame rail up and felt underneath the lower area: oil ! Fired the coach and let her heat up, no sign of leakage, but, no pressure like truckin' down the road, which we're not doing until we head north to a shop we've been happy with in Flagstaff. Anyone had this happen? I'd be curious to see what parts I may/or may not need.

Re: Oil leak in CAT ?

Reply #18 – July 27, 2016, 04:49:58 pm

Quote from: mike leary – July 27, 2016, 02:31:25 pm

Cleaned the frame rail

Mike,

Very impressive; how did you get it so clean?

Trent

Re: Oil leak in CAT ?

Reply #19 – July 27, 2016, 05:10:51 pm

Quote from: TulsaTrent – July 27, 2016, 04:49:58 pm

how did you get it so clean?

Re: Oil leak in CAT ?

Reply #20 – July 27, 2016, 05:15:43 pm

Mike,

Clearly, the engine front mainshaft seal is clean and dry.

Have you looked behind the hydraulic pump pulley to see if its shaft seal is leaking.

It could also be coming from forward on the engine and is being blown toward the back of the coach.

Again, with it cleaned up, the next time it happens you should be able to tell if it is hydraulic oil (clean/clear Delo 400 15-40) or engine oil (same oil, but BLACK).

Re: Oil leak in CAT ?

Reply #21 – July 27, 2016, 05:25:53 pm

My hydraulic pump leaked like yours for a couple of years before I finally decided to get it fixed last year. It was a very slow seep that made a mess but never affected reliability. I tried a Lucas hydraulic additive for a while and that seemed to help but did not cure it. While in the Caterpillar shop in Houston for a valve adjustment, they quoted ~$4k to install a new pump that they were going to buy from Foretravel. Foretravel would have sold me the pump for around $2k. They initially said they did not recommend trying to fix the old pump because the seals were not a replaceable part. When they looked up the price they changed their mind and suggested I try to have a hydraulic shop look at it, just in case. I took the pump to a local Houston hydraulic shop and I think they fixed it for about $180. That was to tear down the pump, check all internals, replace all seals & gaskets, and clean the pump. This did not include the cost of oil or any labor for removing and replacing the pump, which I was able to do myself. I also had the luxury of not needing it done quickly so the Hydraulic shop was able to keep the pump for a week. So far it looks and works like new. Depending on your specific pump and your situation, a new pump might be better for you but, for me, the repair was a great option.

Re: Oil leak in CAT ?

Reply #22 – July 27, 2016, 05:38:55 pm

bdale,

What hydraulic shop did you use?

How long ago?

Always good to keep a list of good shops.

Re: Oil leak in CAT ?

Reply #23 – July 27, 2016, 05:45:29 pm

Quote from: wolfe10 link=msg=240496 date=146965414 Have you looked behind the hydraulic pump pulley to see if its shaft seal is leaking.[/quote

I can't tell. Others have posted (correctly) that the fluid leak could be coming from up front and blowing back. All fluids show no drain, so it's not a big deal. However, if I was in (name the worst place to have a problem) my concern would be serious, given "Bubba's R.V. repair' is the only one within 100 miles.

Re: Oil leak in CAT ?

Reply #24 – July 27, 2016, 06:08:16 pm

Mike,

Indeed, one quart of oil will make a HUGE mess for several thousand miles-- amazing what atomization does.

If no significant loss of fluid in any of the systems (engine, power steering or hydraulic fan) really no short-time issue.

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