Hi Everyone!

Friday the temp here went over 90 degrees and I had to run the A/C constantly just to stay on the warm side of comfortable. The A/C used to be so cold that I would have to turn it down, so I got to wondering if I had developed another leak in the A/C.

Car History:
The car has had A/C leaks before. I had a garage convert it to R134a and fill it with dye. That leaked out in 2 days but they found the source of the leak (can't recall now - think it was a fitting or something). Then it leaked out again 2 weeks later - this time a rotten O ring on the evaporator coil under the dash. Since then, the A/C has held for 2 years.

Today:
Since I've been getting frustrated with other issues on the car and am getting close to wanting to replace it, I didn't want to take it to the garage again. So I bought a $20 A/C gauge to measure the low side system pressure.

Based upon the outside temp of 77 degrees this morning, the chart that came with the gauge said the system should register between 35-45 psi when the ambient temp is at 75 degrees. When I measured it, it was around 32-33 psi. In retrospect this was probably a dumb decision, but I went to Autozone and bought a 12 oz can of R134a with the Dye pre-mixed in with the refrigerant. My goal was to get the pressure up to about 40 psi.

With the car running on Max A/C, I followed the instructions on the packaging by first connecting the canister to the gauge but the valve in the off position, connected the gauge to the low side connector port on the A/C line, then adjusted the valve to puncture the top of the canister, and then began to open the valve to allow the refrigerant to flow into the system.

According to the instructions, you're supposed to agitate the canister while the refrigerant is flowing into the system. But what I found odd was then when I agitated the can, the pressure on the gauge spiked into the 40s, but immediately dropped back down to the upper 20s / low 30s as soon as I stopped agitating the canister and remained at that pressure by the time I finished emptying can into the system. (Don't know if this matters but while emptying into the system, the canister became cold and condensation formed on it.)

The Problem:
The pressure on the low side port now reads at 28 psi instead of 33 psi like it did this morning.

My Question:
Since I had pressure continually through the process of emptying the refrigerant into the system - even when the can emptied out - I presume that my connector was in fact properly connected to the A/C line. So is it safe to conclude that I do in fact have a leak in my A/C system that just doesn't hold pressure about 33-35 psi?

Any thoughts on whether this indicates a leak or if I did something wrong this morning?

Thanks in advance,
Jonathan

 

Did the gauge you bought measure the high and low side pressure?

 

Just the low side pressure. It was the same gauge as found in this kit, but I didn't buy the kit:
Quest/32 oz. of refrigerant and 4 oz. of Sub-Zero booster A/C recharge kit (322) | Freon Charging Kit | AutoZone.com

 

One of our members have posted this somewhere in the forum as a general rule. When the car is turned off for a while and the a/c pressures on both sides equilibrate, the pressure you read in psi for the low or high side should be about the outside temperature (77 psi when it is 77 degrees out). This is a quick check on the system pressure and by no means a measurement to charge the system.

There are more readings to figure out if the a/c system is charged properly on a Honda.

Here are the readings that you would need. This is done with the car out of direct sunlight. Make sure the a/c condenser in front of the radiator is clean. A/C turned on full blast set to recirculate. Windows closed. Take measurements with engine running at 900 rpm.

Outside air temp
Temperature of a/c blowing at the two corner vents.
Low pressure reading
High pressure reading


Never blindly add R-134a to the a/c system. You really need a manifold that measures both high and low pressures and a thermometer to properly measure/charge the a/c system.

 

Thanks for the replies! I plan to go pick up a thermometer tomorrow during lunch - had one but it didn't appear to be displaying an accurate temp, so I won't post the numbers from it.

Is there anywhere I can borrow one of those gauge sets instead of purchasing? $90 (what Advanced Auto charges) is more than I had been hoping to spend . . .

In all honesty, my main goal was to just determine - do I have a leak? I know that I can't repair it myself and I've been thinking about getting rid of the car as it's not in the greatest shape (paint has hairline cracks all over it, trunk leaks due to rust, struts should probably be replaced, manually tranny doesn't shift smoothly even after a rebuild, the car doesn't accelerate smoothly - hesitates a little during acceleration, etc. I live in an apartment so I can't fix all this myself very easily either.)

If it was in fact a leak causing the low pressure and causing the system not to increase in pressure after adding refrigerant, then I would start thinking about buying a newer car. That's why I was hoping to not have to pay a lot of money. I was just hoping that I could keep the car going until next year.

Anyway, I'll get a new thermometer over lunch and post numbers from that tomorrow. Meanwhile if anyone has any suggestions on how to get my hands on the gauge set without buying it (renting etc), that would be great. But if I need to bite the bullet and buy it, guess I can do that too . . .

 

Well, I purchased a manifold gauge set over lunch today and tried to attach the hoses to the manifold, but apparently the thing is defective as those hoses wont screw onto the manifold (too big).

So all I can provide are the A/C temps in the car. Even with the fan running on high, the A/C kept cycling on and off, so the temps at the vents varied a little:
Outside Temp: 79 degrees - Dew Point 69 degrees
Right Corner Vent: 45-48 degrees
Left Corner Vent: 41-44 degrees
NOTE: I expected the right corner vent to be colder than the left since the evaporator is on the right, but that was not the case.

Are these temps normal? If so, is it worth still testing the pressures with the manifold gauge set tomorrow?

Thanks,
Jonathan

 

Not sure if autozone, carquest, ect rent out ac manifold gauges or not, you will have to call them.

Since you have dye in the system, have you seen/found any leaks?

 

Sounds like you picked up the wrong set of manifolds.
There are 2 types
R12 and 134a

I thought most manifolds came with the adapters so you could check either system.
I am not very knowledgeable in a/c systems so someone else will have to chime in on solving the rest of your problems.

Good Luck!

 

I just read your post again and one thing I do know is most A/C systems are only able to produce temps 30 - 40 degrees lower than ambient temps, which it looks like yours is doing.

 

Just ran the UV light over the visible portion of the A/C lines and I see no sign of leakage. Although, the last time the system leaked it was at the evaporator coil which I cant see since it's behind the firewall under the dash.