Arts and crafts: Honda Air conditioning repair

As I mentioned previously, the AC on my Honda is not working.  I tried adding refrigerant and that blew right through and failed to maintain pressure.  That was actually good news since it meant the compressor was fine.

So I invested in a bottle of leak detector and the UV detector light and spacial colored glasses.  I spotted the leak coming from that silvery pipe in the center of this picture, on the side where it is touching that black Plastic gizmo on the Air supply conduit.


So, I ordered a new aluminum line on-line.  $50.  Pre-bent and from a OEM Honda parts dealer. If I were from Cuba, I could probably have brased that pipe and sealed the leak without even removing it from the vehicle.  If I were from Alabama, I could have done it with JB Weld.  If I were particularly skilled, I would have used some fresh aluminum tube and bent it myself with tube bending tech, and added flanges on one end and brased the fitting on the other end.

Maybe next time.

So, I gathered the pieces together. including some specialty tools.  I got The vacuum and manifold gauges for free by borrowing them from AutoZone.



And since I will be working outdoors in the Virginia summer, I also planned for refreshments.  I cannot stress enough how important it is to maintain hydration.


… And…  um.. Electrolytes.


Since I have the system already gas free (from the leak, not because I hate Gaia and vented my refrigerant to the air), I am going to replace both of the gas valves too.  The old ones are 15 years old and likely to fail some day.  If you are working on your AC, ensure the gas has been removed first and there is zero pressure in the system. Mine is because of the huge hole in that pipe.


This little kit comes with a tool, but you can also use a tire valve core puller.  In this case, the tool did not quite fit and I have to file it down to make it fit.

Now Ready to get started.  To remove that pipe it is secured at one end by a 10MM bolt and on the other by a flange fitting.  The bolt is on the AC dryer unit  and the flange fitting is near the firewall.  They both come loose easily.  Be careful when working with this pipe.  It is soft aluminum.  Overtightening it will easily strip it.


In this picture of the top of the dryer, you can also see a silver label on the car frame.  That label tells you important information about the AC system, like how much R-134 the system will need to refill it.  It goes by weight.  Then you read the labels of the cans to determine how to get the right amount.  Don’t forget to use the kind with PAG oil in it, but not too much.  My repair manual tells me my system needs 2 OZ of PAG oil, so those cans with 3.5-5 oz will be too much and the cans with only .5 oz will be too little.    You will notice in the picture above that I am using two different brands of R-134.  This gives me the best combination of ingredients that are closest to what my system needs.  The picture below also shows the location of the High side valve fitting.


Now that the pipe is disconnected, you may need to remove some other odds and ends to give yourself room to work.  This pipe easily went in AT THE FACTORY, and since it have no moving parts, was expected to never need to be replaced.  So, it will take form creative puzzle solving to get it back into the same space. I removed the battery, battery stand, the top of the Air handling hose, and a few brackets that hold the AC lines.


So, I got out the offending pipe.  Here is what it looks like.  The longitudinal cut is the leak.  The lateral cut is from bending the pipe while removing it.


Before I put the new tube in, I install the new o-rings I bought with it.  Then looking at the part, I discovered that it is already equipped with O-rings, and the ones I paid $5 for, would not have fit anyway.  This is odd since I ordered these parts from the same place, and using the same diagram.


Fitting the pipe back in is challenging.  It takes a bit of care to not bend the new tube and fit it back into it’s original position.  It makes me wonder why some smart guy hasn’t replaced this part with a flexible tube by now.  I suspect it is because bending aluminum tubes is cheap and easy.


I did get my part in though.  In the interest of saving time, I then skipped ahead a little.  I hook up the manifold gauges (blue to low side, red to high side and yellow to the vacuum).  Make sure all the fittings on the gauges are tightly sealed and the valves are closed before you hook it up.  Then open both sides, red and blue valves and turn on the vacuum.  Then let it do it’s vacuum thing for about an hour.  During that time, you can put your car back together.


You should see the left gauge show vacuum all the way down to -30 after just a few minutes.  But that doesn’t mean you are done.  If it doesn’t, then you have a leak in your system, or the valves aren’t open.  Remember, there are two valves on the gauge cluster and another two valves on the ends of the red and blue hoses.  All need to be open at this point. Keep vacuuming for a full hour.  This will help remove all the air and any moisture in your system.  Both are bad for your AC.  And don’t neglect to check your vacuum pump oil supply.  This one I borrowed drank that stuff like a backyard mechanic on a  hot day with a jug of blue sports drinks and .. um… electrolytes.


When you are satisfied that the vacuum has done good service, it’s time to erase all that hard work and put stuff into the system.  You should be able to turn off the vacuum and not see a change in the vacuum level on the blue gauge.

  1.  SHUT OFF THE HIGH SIDE VALVE ON THE GAUGE CLUSTER.  Leave the valve at the end of the high side hose open.
  2. Shut off the Low side valve on the Gauge cluster.  Now your yellow hose is isolated from your system.  disconnect the vacuum from the yellow hose.  If your blue side gauge goes back to zero, you failed to follow steps one and two.  Reconnect the vacuum and let it run for another hour with all valves open.  Then try again.

image3.  Assuming you still have -30 on the blue gauge, connect your first can of refrigerant to the yellow hose.  Puncture the seal at the top of the can, using the special valve that comes with the gauges.

4.  Start the car, turn on the AC to full cool.

5.  Open the blue (low side) valve on the gauge cluster.  Your high side should be still closed on the cluster and both valves that connect to your ports should still be open.  If you did this part, your gauges should look like this after only a few minutes.


After about a minute, you should hear your AC compressor kick on.  It wouldn’t before because it has a safety shut off circuit if it has low pressure.

Shake the cans once in a while until all the contents are in the system.  Shut off the blue valve on the cluster to change cans on the yellow hose. You will be able to tell when the can is empty because it will feel like an empty can.

When you are done, close off all the valves, remove them from your car ports.  Enjoy your cool air.


About No One

I am totally non-threatening
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3 Responses to Arts and crafts: Honda Air conditioning repair

  1. JN says:

    Nice writeup.
    I had an issue with my car where the ac sticker was actually wrong. It said 1.8lbs when it should have been 2.3. Had to spend hours tracking down that info just to get the mechanic to put an extra .5lbs in so it would work properly. (Compressor died at 205k miles)


  2. Pingback: Adventures in Commerce |

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