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Air Dryer Leaking Moisture???
Checking the underside of the bus today and seems that I have a moisture “leak” around the air dryer. Is this possible?
I’m almost certain it is the air dryer that I see. It’s in front of the drive axle on driver side between center of bus and drive tires.
So my question is…..does the air dryer have any fluids in it that could be leaking? I know it isn’t water because bus has been parked since the last seminar and inside storage facility.
System is holding pressure good when operating. It cycles and I can hear the spit when it tops off the tank. I know it needs to be checked/repaired but is this something that should not be driven or will possibly put me on side of road?
Thanks for input.
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11 Replies
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The air dryer removes water from the air system. That is what it is designed for. However, if the air compressor is wearing out, engine oil can also appear in the output from the compressor. This would be visible under the dryer as some of it gets exhausted with the water each time the dryer goes through a purge cycle. Not all the oil will exhaust though.
Oil will eventually cause the dryer to become inefficient. It is another good reason to change the cartridge often to keep the air system as dry as possible.
I wonder if you are seeing some oil drips under the dryer…..
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The fryer filter was changed last February. Yes, I did see 2 or 3 very small drops of what appears to be oily fluid on the garage floor.
So I know I need to get it repaired but should I trust driving from SC to ETLC?
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It may be leaking at the Purge Valve, not shutting off after the sneeze. If it’s a small leak and doesn’t require the compressor to continually cycle it should be OK to get to Jeff’s. Check with Jeff.
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Jacky,
If you are seeing what Mark says is oil (maybe water also) he is probably correct.
I believe you have the Haldex dryer and like mine and I change my element every 2 years and see no oily residue near the purge, nor do I ever see moisture or oil from the wet tank.
If you can verify you are seeing oil you may have a compressor passing oil and given the recent service interval it would be worth checking. Oil passes every compressor, but not to the extent that you would see it in such a short period of time.
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Thanks for the replys and information. I’m checking more today and attempting to drain wet tank (with jack stands and jack under frame as stressed by Jon any time working under bus). Looks like a trip to our beloved ETLC Resort where the great minds and donuts are.
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Well looks like good and bad news. Was able to get under the bus and it appears that I do have an oil leak coming from the dryer area. Good news is that both the wet tank and primary tank had no moisture of any type when I opened the valve for about 2 seconds. Will be heading to Jeff’s Resort for repairs soon.
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You can check with Jeff about how bad the oil seems to be. There always seems to be a small amount, but if it gets too bad, it will screw up the cartridge so it won’t work very well to get rid of the water.
I have a small amount around my drain, but it does not seem to be getting worse, and it has been there since I got the coach. I also have no moisture in my tanks, but I change out the cartridge pretty much each year. I am willing to spend a bit to keep the air system as clean and dry as possible.
The air compressor is kind of pricey if I remember…$12000 give or take. Jeff will know for sure as he has replaced some.
Good luck…hope you don’t need the compressor replaced yet….
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As Mark pointed out, a small amount of oil is normal, I’ve never had a coach or truck that didn’t produce tiny amounts of oil at the dryer or wet tank.
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Jacky, did you ever get to the bottom of your issue? Did you need a new compressor?
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Yes and no Andy. Jeff replaced the compressor last November and I thought things where good. However I just checked under the coach today and I still have a sizable amount of oil residue sprayed around the air dryer and bottom of bus. I did a quick drain of all the tanks and had no moisture from any of them. I’m going to call Jeff to ask if he thinks the air dryer may be bad. I just don’t think there should be this much oil moisture coming from the dryer.
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Generally speaking oil will pass through compressors, with the amount increasing as the compressor ages.
The cartridges in the air dryer end up collecting the oil because it coats the dessicant and as it does so it reduces the effectiveness of the dryer. That is why dryer elements need to be changed.
There are two clues to the reduction of effectiveness of the air dryer cartridge and they are visible coating of oil in the area around where the dryer purges and indications of moisture in the wet tank.
The oil visible on the coach frame could be residual in the dryer from the previous compressor. As long as the wet tank shows no moisture I believe that is an indication the dryer is not in need of service and that it is doing its job.
I have been changing dryer cartridges every two years and on that schedule I never see moisture in any tank, and I do have a trace of oil residue around the dryer purge. I check tanks every 5000 miles.
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