Why did my 5 hp, 20 gallon compressor leak water oil?

[mtc]

let's just say this is not for automotive use, but since you guys are mechanical geniuses , i'd thought i'd give it a shot in here...

never drained it for the time in my possession 3.5 years, i know i know, hard place to access. it's got to be 19 years old and never drained....

this today i noticed after cleaning up the mess, over a gallon of oily watery sludge on the floor, called a firend and he told me to drain it.

so i unplugged it and bled the air out and wrenched the bottom drain plug , and the remaining sludge came out, it was not pretty.

put it back and plugged it in, it started to run and fill... and it holds 175 psi of air, and is working fine


mystery...

what hole allow the ~1 gallon of watery sludge to come out yet is has no holes in the tank since it hold air? no corrosion, no rust

help explain please and thanks

[FJmonkey]

The water comes from the moisture in the air. It will also rust your tank from the inside out. So drain the tank every once in a while. How often? You will need to determine that. The more air the compressor consumes and the humidity of the air will affect how much water gets in the tank. I drain the compressor at work once a month and get about a cup of water. This compressor gets used way more than the average home use. The oil has to come from the compressor, unless your part of Los Angeles has really oily air. 

[mtc]

The water comes from the moisture in the air. It will also rust your tank from the inside out. So drain the tank every once in a while. How often? You will need to determine that. The more air the compressor consumes and the humidity of the air will affect how much water gets in the tank. I drain the compressor at work once a month and get about a cup of water. This compressor gets used way more than the average home use. The oil has to come from the compressor, unless your part of Los Angeles has really oily air.  

maybe the compressor piston rings are letting oil thru, not a bad thing, oil will prevent rust in the tank, i saw no rust in the mixture

but

how did 1 gallon of watery sludge end up on the floor all by itself?

[Pat Conlon]

Ghosts

[FJmonkey]

I see, before you drained it... Whack it with a rolled up news paper and teach it to use back yard.

[mtc]

I see, before you drained it... Whack it with a rolled up news paper and teach it to use back yard.

that would be tool abuse , a reportable offense

[red]

mtc,

If the compressor is difficult to access, most tank drains use standard plumbing threads.  Figure out what you need, to add a few feet of common plumbing pipe (metal, not plastic) to the tank drain.  The new pipe should end in a cap or valve (for draining) that is in an easier location for you.  Remove the current drain valve fitting from the tank bottom, and replace it with the new plumbing.  The new drain piping will make it much easier for you to drain any liquids from the tank on a regular basis.

Just a thought . . .
.

[FJmonkey]

This is what I did when my drain valve failed on my home compressor. Very easy to blow out any water.

[mtc]

mtc,

If the compressor is difficult to access, most tank drains use standard plumbing threads.  Figure out what you need, to add a few feet of common plumbing pipe (metal, not plastic) to the tank drain.  The new pipe should end in a cap or valve (for draining) that is in an easier location for you.  Remove the current drain valve fitting from the tank bottom, and replace it with the new plumbing.  The new drain piping will make it much easier for you to drain any liquids from the tank on a regular basis.

Just a thought . . .
.

genius! would i have to flare tubing and compression fittings? cause it was murder doing it today

[Ted Schefelbein]

No. It is pipe thread, a little pipe dope or Teflon tape will do it. I would guess you don't do any paint with that compressor, or you would have figured this out long ago, because you would have had spoiled paint from the impurity's in the air it delivers.
Single stage compressors make a bit more moisture than two stage units. You can actually buy solenoid actuated electric drain valves, but, in my experience they are troublemakers. Better just to come up with a schedule for tank draining and to stick to it.
I would inspect that tank. 19 years in water is a long time. Perforated tanks aren't funny.

Ted

[red]

mtc,
If the compressor is difficult to access, most tank drains use standard plumbing threads.  Figure out what you need, to add a few feet of common plumbing pipe (metal, not plastic) to the tank drain.

genius! would i have to flare tubing and compression fittings? cause it was murder doing it today

mtc,

I do not suggest using flare tubing and compression fittings.  Common threaded metal plumbing pipe is the answer, easy and  cheap.  Use RTV sealant or pipe dope (Teflon tape) on the threads to help the threads seal at each connection.  The plumbing place can show you how Teflon tape is used.
.

[mtc]

No. It is pipe thread, a little pipe dope or Teflon tape will do it. I would guess you don't do any paint with that compressor, or you would have figured this out long ago, because you would have had spoiled paint from the impurity's in the air it delivers.
Single stage compressors make a bit more moisture than two stage units. You can actually buy solenoid actuated electric drain valves, but, in my experience they are troublemakers. Better just to come up with a schedule for tank draining and to stick to it.
I would inspect that tank. 19 years in water is a long time. Perforated tanks aren't funny.

Ted

yes i felt a pin hole there just now, seal with the sludge, what do i do?

[fj1289]

How big/heavy/bulky is the tank?

Replace it is the obvious answer.   I see them come up on Craigslist from time to time when the pump or motor die. 

One answer you may get away with is to do your best to clean the inside of the tank.   Get a rubber stopper - like the type with the bolt or lever to make it expand into the hole.  Then mix up a quart or more of fiberglass resin and pour into the tank, put int the stopper, and let it dry.   Hopefully it will fill in your pinholes.  And hopefully the rubber stopper will keep it out of the threads so you can replace the drain fitting.   And hopefully there is enough safety factor built into the tank it will serve for many years without an explosive failure.  I don't know where or how the tank is mounted and what the results of a rupture would be.

Or replace the tank.   

[red]

No. It is pipe thread, a little pipe dope or Teflon tape will do it. I would inspect that tank. 19 years in water is a long time. Perforated tanks aren't funny.
Ted

yes i felt a pin hole there just now, seal with the sludge, what do i do?

mtc,

If you have a pinhole due to rust (what else, really?), the welds in that tank are very likely to fail one day, and maybe not very long from now.  Rust attacks the welding.  You got twenty good years on that old tank, so I would not complain.  The oil in the water tells me the compressor itself is getting old, too.  It's your call about rebuilding or replacing that compressor.  Contact the manufacturer, if possible; there may be a rebuild kit available from them for the compressor.  If the compressor is doing what you need, it may be okay as it is, for some time.

As for the rusted tank, by far the best option (short of an entire new compressor assembly) would be a new air tank.  The new air tank does not have to look or mount like the old tank.  It probably does not need to be twenty gallons, either, but that old rusted tank you have can be dangerous.  Just like the drain line, you can plumb up a common iron-pipe connection between the compressor and a new air tank.  Make sure that any new tank is rated to hold the full pressure that your compressor can put out.  I would not attempt to repair the old rusted tank.  Make sure that the new tank has a drain valve to remove oil and water from the tank.  You can install an oil/water separator into the air line that keeps the compressed air from the tank "pure," as in free of oil and water.
.

[FJmonkey]

yes i felt a pin hole there just now, seal with the sludge, what do i do?

The answer you seek is right here. The tank rusted to a weak spot/pin hole. When it was re-pressureized (not sure if that is proper word) the water/sludge was pushed out and left a mess on the floor. Keeping pressure in this tank will result a larger hole. How much pressure it takes to make this hole will determine how explosive the result is. Chances are the area around the pin hole are quite thin and will blow out with out much of a violent result. But the tank is now scrap.

Oil is lighter than water. It floats. So the water will sit at the lowest parts of the tank and corrode it. regardless if oil is in the tank.