# Big farting noise from compressor



## dadbod1954 (1 mo ago)

It's a Speedaire, two stage, 80 gallon from circa 1977. It started making this noise about 5 years ago. A mechanic thought it might be a head gasket.

I turned the pressure down to 125 from 150 since I don't need any more than that anyway. That definitely helped.

The timing of the noise is inconsistent. Sometimes it'll run through a cycle without making any noise at all. Sometimes it farts just a little bit. Sometimes it farts a lot.

I don't honestly need this compressor all that much anymore but I sure don't want to damage it and I don't want to lose it. 

Please advise and TIA.


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## sledman8002002 (Jan 28, 2021)

Welcome to the site dadbod!


dadbod1954 said:


> A mechanic thought it might be a head gasket


It could be but I would think you'd hear it the entire time the motor is running. Easy to check by removing the head, you'd be able to examine the reed valves at the same time. If you do remove the head, keep an for any small locating pins/dowels.
Could just simply be a check or relief valve.
Oil level is good?


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## dadbod1954 (1 mo ago)

Thank you sir. Yes oil level is good. It's been so long since I went into a compressor until I forgot all about them having reed valves and check valves so thanks for reminding me. I may soon be moving this compressor to another part of my shop. I'm mostly just wanting to be sure that it's fit to save before I go to the trouble. Now that you've mentioned the check valve, you've given me the idea to hold my hand over the air intake to see if what I'm hearing is back pressure through the air intake. So I'll make sure about that first and again thank you.


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## sledman8002002 (Jan 28, 2021)

You're welcome. I hope you find it to be a quick fix and well worth the trouble of saving. I get what you're saying, speaking for myself, with the advent of strong cordless impacts, my compressor use is roughly 50% of what it once was.


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## dadbod1954 (1 mo ago)

sledman8002002 said:


> You're welcome. I hope you find it to be a quick fix and well worth the trouble of saving. I get what you're saying, speaking for myself, with the advent of strong cordless impacts, my compressor use is roughly 50% of what it once was.


Actually I'm using it to air-pump water out of an old shallow well that has no power to it. It's really good spring water but extremely slow, so it would burn up a modern pump. I have an old 500 gallon propane tank that I want to move out there, then charge it with a hose from this compressor. Then I can pump water for hours without a compressor running,
especially not stop-start running. This doesn't really have all that much to do with this thread but I guess I just want to tell about it.


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## sledman8002002 (Jan 28, 2021)

dadbod1954 said:


> This doesn't really have all that much to do with this thread but I guess I just want to tell about it.


It's all good dabod, I myself like extra information within a post.


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## Llanboyo (26 d ago)

Hi dadbod simular guess to the previous response sticky non return valve/check valve or could be the safety valve sputtering if one of the heads is going overpressure the Reed valves chalk up and stick over time might be worth giving them a clean just have some instant gasket at the ready because 9 times outa ten it will break hope this helps


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## dadbod1954 (1 mo ago)

Llanboyo said:


> Hi dadbod simular guess to the previous response sticky non return valve/check valve or could be the safety valve sputtering if one of the heads is going overpressure the Reed valves chalk up and stick over time might be worth giving them a clean just have some instant gasket at the ready because 9 times outa ten it will break hope this helps


Thank you sir, I hadn't thought about the safety valve.


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## 4v Shane (16 d ago)

The noise can be misleading but more times then not its a faulty check valve on the tank/near the pump inlet. The split second it fails to seal will cause that noise. I had a similiar occurance happen and carbon/debri had built up in the cylinder area of the valve and prevented it from seating and then attempting to back feed. Probably time for some good service and scrubbing of parts. If you dont already have an ultrasonic cleaner spend the 60 bucks at HF and grab one. Its amazing the results you can get from it.


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## dadbod1954 (1 mo ago)

4v Shane said:


> The noise can be misleading but more times then not its a faulty check valve on the tank/near the pump inlet. The split second it fails to seal will cause that noise. I had a similiar occurance happen and carbon/debri had built up in the cylinder area of the valve and prevented it from seating and then attempting to back feed. Probably time for some good service and scrubbing of parts. If you dont already have an ultrasonic cleaner spend the 60 bucks at HF and grab one. Its amazing the results you can get from it.


Thanks very much. I haven't had time to work on this thing yet. The more I have read, the more I've come to the conclusion that it probably is the check valve.

Most interesting is that I started it recently on a cold morning and it didn't fart at all. I figured right then that it meant that the problem was not inside the internals of the compressor. Now I'm thinking that the cold may have actually helped the check valve to seal by contraction.

I have an ultrasonic cleaner. Thanks for mentioning that.


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## 4v Shane (16 d ago)

dadbod1954 said:


> Thanks very much. I haven't had time to work on this thing yet. The more I have read, the more I've come to the conclusion that it probably is the check valve.
> 
> Most interesting is that I started it recently on a cold morning and it didn't fart at all. I figured right then that it meant that the problem was not inside the internals of the compressor. Now I'm thinking that the cold may have actually helped the check valve to seal by contraction.
> 
> I have an ultrasonic cleaner. Thanks for mentioning that.


The contraction of the material used in the check valve. Typically its a composite cylinder that will expand and contract way before any metalic material. Happy New year and goodluck!


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## dadbod1954 (1 mo ago)

That makes sense. Happy New Year to you as well!


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