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Small oil leak at the alternator shaft
I tightened the 6 or so hex nuts that hold the assembly together. I assume this needs further attention. Not sure if its related but my left prevost gauge shows nearly 28 v which is max scale.
Wave
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25 Replies
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There is a kit to replace the seal on a 50DN. It is not a big job to replace the seal and seal issues are common.
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I don’t remember seeing one that didn’t leak. A constant problem but seal kits are cheap.
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Let it be and watch it. When we bought (2015) our current coach, we thought after pDI, we’ll have Marathon replace our 50DN because of a small seep. Fast forward to present, after three more rebuilds, one lasting only 5000 miles, we wished we had left the original alone until it had major issues. We have a local 50DN rebuild shop but every time one of theirs fails, I take it back and new one has less and less warranty and it’s never their fault, we have to pay S and S for removal and replace, and we provide parts trans port. So,no our recommendation unless catastrophic leak, leave it be.
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+1 on Jim’s recommendation…then switch to air cooled. My experience with new and reman oil cooled 50DN’s was terrible. My air cooled unit now has over 100K on it.
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I suppose its all sealed and not able to add oil? If it fails while driving what would be the result?
Wave
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If you have oil in the motor that 50dn has oil, it feeds from your motor
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Joel is right, get an air-cooled and be done with it. I went through 4, 50 DN re-built’s and the air cooled I replaced them with is reliable, easy to install and it doesn’t contaminate the engine oil, no seals to replace, etc,etc.
Fred
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I had no idea it used engine oil. That is good news because its not using any oil between stops.
Wave
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JOel,
How difficult is it to change out to the air cooled? Where did you have it done.
I am am pretty well done with the DN50 as well. next sign of a significant leak and it’s gone.
Bill
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Oil leaking where it should not is annoying to me. But I have reached the point where the cost or effort to make an annoying leak go away is disproportionate to the benefit my attitude is to just buy an aerosol can of brake cleaner.
A cost of $5 per can for 2 or three times a year use to flush away oil is an acceptable alternative to the cost and effort to repair or replace some items. I appear to have a rear oil seal leak on the engine which shows as oil on the oil pan driving me nuts every time I change oil, but the alternative is a cost and time involved disproportionate to the benefit.
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Bill: The air cooled is manufactured/remanufactured by Penn-Tex and is basically an oil cooled 50DN modified to function as air cooled. As such, it is bolt-in. The installation kit (optional) includes plugs and caps as necessary to eliminate the oil supply and return.
I did encounter a problem (as far as I know, I’m the only one) with the top 2 bolts on the alternator bracket to engine failing possibly due to increased vibration due to elimination of the large drain hose. I fixed it easily by drilling the bolt holes out to 1/2″ and installing grade 8 bolts. Might also be a good idea to install the detroit S60 timing case cover braces if your coach doesn’t already have them. I believe all 2007’s have the braces factory installed.
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This is just an observation and might influence some decisions.
The oil does serve a purpose and it is primarily a means of controlling alternator temperature. The flowing oil is pulling heat from the alternator as loads create heat.
Joel has a Liberty and it is highly unlikely his air cooled 50DN is subject to heavy continuous loading. Less load, less heat.
But on coaches without OTR, and on which A/C units are being operated on inverters as opposed to a generator when the coach is in motion the alternator is under load. The loading is less on a 24V coach, but tends to be substantial on a 12V coach. Just a single A/C draws a running current of 130 amps on 12V and 65 amps on 24. That does not include all other electrical loads ranging from other inverted loads to battery charging to headlights, and other power requirements.
As with almost everything on our coaches heat is the enemy and the life of a lot of our components and fluids is shortened as heat rises.
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True, but, but, but…
My alt is rated at 24 v and either 300 or 330 amps (??). Don’t know at what ambient temp they rated it or if that’s continuous but
I regularly park discharging my 6- 8D’s, 4- 31’s and 2- 27’s (all hooked together) to about 12-12.1 volts and let them recharge on the alternator which starts out at a very high load (150-200 amps as I recall, I’d have to go back and look at my gauge) and tapers downward over the roughly 3 hours of charge time. In addition, it’s not unusual for me to run OTR A/C 8-12 hours straight…I believe it uses about 50-70 amps to keep all running.
Of course, don’t forget, I’m cooling my alternator with maybe 160F air (under summer conditions) while you’re cooling yours with 190F oil.
The final straw came for me when one of my oil cooled remans bolts holding the two halves together came loose and dumped a few quarts of engine oil. I was lucky to catch the problem without serious engine damage.
I’m now approaching 100K miles on my air cooled. If it failed now, I would still replace it with same.
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Jon,
Your oil leak may not be the rear seal. Check the rear cam cover. They are notorious for leaking and look like a real seal leak.
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Ditto what Mikee said, you’ll have oil up high above the compressor and it’s hard to see with the alternator in place, you have to crawl in there with a flashlight to see it and you’ll have oil run down the rear side of the motor under the alternator mount. That was one of the reasons they came out with the stiffener kit for the accessory case on some years, suppose to prevent needing a diamond seal, an expensive repair. The accessory case moves slightly and will cause the oil leak.
1999 XLV X-6872, liberty #440
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