Porter Cable Air Compressor Leaks Air

Published Categorized as Porter Cable 23 Comments on Porter Cable Air Compressor Leaks Air

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Air leaks can be a significant source of wasted energy on Porter Cable air compressors. They will cause pressure drops in the system, as well as resulting in additional costs. This article will provide why your Porter Cable air compressor leaks air, and the most likely locations if you’re looking to diagnose and fix the issue!

Table of Contents

Why Is Air Leaking From My Porter Cable Air Compressor?

Porter Cable air compressors leak air for a number of reasons. It could be that the fittings are not sealed, the hose or pipe has a crack or a compromised component that needs replacing. Here’s a list of the most common components that may be causing your Porter Cable air compressor to leak:

  • Condensate traps
  • Couplings
  • Cylinder rod packing
  • Disconnects
  • Filters
  • Fittings
  • Flanges
  • Hoses
  • Lubricators
  • Point-of-use devices
  • Pipe joints
  • Pressure regulators
  • Shut-off valves
  • Thread sealants

To help you locate your Porter Cable air leak, you typically have 3 methods; listening and feeling, applying soapy water, and using an ultrasonic leak detector. Listening and feeling for air leaks is the simplest method, but not always the most accurate. Applying soapy water to an area where a leak is suspected is a reliable but time-consuming method.

The best method for detecting compressed air leaks is this ultrasonic leak detection, which has quickly become a standard method in the industry. For more information on how to find and fix leaks on your air compressor, visit our guide!

Useful Pages on Air Compressor Leaks

FAQs (Frequently Asked Questions)

How do you fix a leaking Porter Cable air compressor?

To fix a leaking Porter Cable air compressor, you first have to locate the source of the leak. You then may need to tighten connections, repair or replace components, or swap out the hose or pipe section that is compromised.

Reader Questions & Responses

Porter Cable Air Compressor Leaks Air – Portable Air Compressor Troubleshooting


I have a CGBN125A-3 Porter Cable that has developed a leak and removed the cover to inspect which makes it impossible to run the unit to test for leaks. The hoses look good but did notice the metal tube attached to the cylinder head has a lot of play.

Could that be the problem, says Stan from Hardeeville S.C.


Well, Stan, it’s a bit hard to tell from here. Is air leaking from that fitting? If not, then no, probably not the problem. Makes me wonder how you know that the compressor has a leak?

I’ve tried to find an image of the Porter Cable CGBN125A-3 compressor but have been unable to do so. Perhaps you could upload a photo?

Porter Cable Air Compressor Bleeds Air From Cylinder Head


The compressor comes to full pressure, shuts off correctly then leaks air from a pinhole in the cylinder head near where reed valves are located. Is the pinhole supposed to be there? what is supposed to keep air from bleeding out there?

Porter Cable C2005 air compressor
Porter Cable C2005 air compressor


Mike, once the air compressor shuts off, there is no way compressed air is supposed to bleed out anywhere for more than a second or two.

The tank check valve is supposed to keep the compressed air in the tank until you open a downstream airline to an air tool to use the air. So, if the air is bleeding out anywhere, then I would surmise that the tank check valve is fouled or failed.

I cannot locate a photo of this compressor to confirm it, but here is what I surmise. Assuming that the pinhole is not a structural failure (and I don’t know that) then it may be there simply to bleed air off the cylinder head, may bleed air all the time when the compressor is running but since it’s a small hole, more air goes into the tank when the compressor is running than out the hole.

Then, when the compressor stops, the left over-the-piston air bleeds out the hole, and the compressed air in the tank stays there unless you use it, and unless the tank check valve is wonky.

Porter Cable C7510 60-Gallon compressor Hissing Air Between Cylinders


Ok, you said there were no dumb questions, so here goes.

I have a Porter Cable 60 gallon compressor.

There is a copper line connecting the 2 cylinders. In the fitting into one of the cylinders, there is a small nickel diameter valve – it leaks a short squirt of air with every stroke of the cylinder. It has a small needle that pops out of it. It leaks air from the minute the compressor is activated (even with zero pressure at the start) and continues until approximately 100 psi, at which point it stops emitting air, seals up, and the compressor continues to run until it reaches 120-126 psi and the compressor stops.

I don’t think it takes a particularly long time to come up to pressure and the compressor seems to work fine, but this bugs me. Is this the way this compressor is supposed to work? I cannot find anything about this valve in the parts schematics that I find online. If you are standing in front of the compressor the valve that I am talking about is on the cylinder to the right, ie the cylinder furthest away from the motor. Does anybody have any ideas?

Thanks, Greg


Greg, I’ll take a stab at it, and invite anyone else with this Porter Cable c7510 air compressor to join in.

What I think you are seeing / hearing is the PRV in the line between cylinders. That suggests to me that you are getting back pressure in the line between the two cylinders, causing the PRV to pop open intermittently, and that suggests to me that you may have an intake valve issue on the second cylinder.

Just my 2 cents worth. Anyone else?

If you have any questions regarding a Porter Cable air compressor leaking air, please leave a comment below, with a photo if applicable, so that someone can help you!

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My 150 psi compressor i can hear air leaking from the fins to the left of the label. Could this be the pump seal?

I had the exact same concerns regarding air leaking out of the manifold.
After reading this post I confirmed it was the check valve that was stuck open.
I cleaned it out and everything works great.

That’s great!
Thanks for letting us know.

Valve on the bottom of tank is leaking . Can I fix this or leave it to a pro?

Probably. You refer to the tank drain valve, yeah? All but maybe some PC I’ve not seen use a quarter inch (pipe thread) drain valve. Insure the tank pressure is zero or very close to it, remove the old valve, and replace with the new one. You can use any wrench that fits snugly. If you have a local big box or HFT, you can get a new one there. Get some pipe tape or dope while you’re at it. Here’s some info on how to do that correctly: https://about-air-compressors.com/fitting/ Pay attention to the pipe size chart if you’re not… Read more »

You might read my reply to Richard Spooner, just below.

I have porter cable pancake compressor that leaks badly from the drain valve on bottom of the tank. I see that the plug has a borehole that could regulate as a valve, yet no matter how much of the threaded bolt is inserted or withdrawn, the leak is continual and loud.

Yeah, those valves suck. It’s almost certainly 1/4 inch pipe threads (about 3/8 actual diameter). Remove it and replace with a ball valve from your local HFT or big box store.

What Doug said. I got a replacement valve on Amazon for less than $6. It’s an easy fix.

I have a similar problem. In the first photo you can see where the air is leaking from the manifold (area circled in red). Behind the manifold you can see a very small pin hole (green arrow pointing to it) that looks machined and part of the manifold. And lastly the middle photo shows what I suppose are reeds. So what happens is the compressor just keeps running and getting hotter without building any substantial pressure and leaks air through this pin hole. Is there a problem with the reeds? Are they supposed to block this pin hole at some… Read more »

“without building any substantial pressure and leaks air through this pin hole.” That pinhole is the “unloader”, I believe. Are you getting air from there when the compressor is off and there is *some* pressure built up? That would mean the check valve is leaking. You may be able to clean it and get it to seal. Which may fix the pressure problem. But I’d start with that, if the other side of the valve plate is in good shape. I don’t think it’s a major problem, but check the slightly raised finger in the middle pic. If it’s not… Read more »

So I cleared the area under what I’m going to call a “reed” (the circular shaped plate, bottom one of the three in the middle picture) and it seems to rest more flatly. I ran the pump and it almost immediately started the leaking sound again but I let it run to build some pressure. The black rubber tubing got warm to hot but eventually as the pressure built the hissing stopped and at 150 PSI the compressor stopped on it’s own with no leaking.. I guess what I’m wondering is whether or not you can adjust the pressure where… Read more »

There are no adjustments, other than the regulator and replacing parts. The check valve is the thing between the tube from the pump and the tank. If you have a c2006 type 2, it’s item 8 on the drawing. Many of the other types have it as part 11. It reduces the load on the pump and motor by stopping back pressure from the tank, and likewise holds the pressure in the tank after the pump stops. If you have air coming from that pinhole unloader after the pump stops, that’s the check valve leaking. The purpose of the hole… Read more »

Mine was doing the same thing. Carefully took the clamp off so that I can reuse it. I then took the check valve off. When I blew through the part where the hose goes in the air went right through. This is a sign that it’s defective. I sprayed some lubricant in it, and gave it a cleaning. It sat for about 20 minutes and then I reinstalled it. That fixed the issue. I can assure you the problem is the check valve. 15 dollar part

I got a Porter Cable C2006 Type 2 Compressor and the cylinder head is leaking air after it shuts off. I thought the cylinder head gasket needed replacement, which I did. The leak did not stop. Is it safe to say that the check valve is the problem?

Where from the cylinder head is air leaking? Is it the cold start valve? If so, you are spot on, it’s the tank check valve that is the likely culprit.

The hole in the lower middle of the cylinder head pic is where it is leaking. I guess that is where the pin hole is located.

That’s the intake. Air should go in there never to be felt again until it comes out somewhere else.
Your valve plate is malfunctioning.
I’d inspect it before ordering a new one – it may just be obstructed by debris or something.
You may be able to repair it if you have the tools and patience and time, or just buy a new one.

Good luck and have fun…

P.S. to the other one:
The check valve should prevent a leak from the intake valve, too, so it may also need a cleaning or replacement.

jt dlest and Bill, I don’t see a cold start valve on this.
But there are two hoses to the tank, either of which could be leaking, but as you say, if it’s from the head it’s probably the check valve.

My porter cable compressor leaks from the cylinder head, is any hope for this unit?

Model number, please and could you upload a photo of it?

Check valve. 100% 15 dollar part