When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hi. I have a 1994 Honda Civic CX. I have been having trouble with getting my A/C cold. It probably blows out 65 deg. air. It comes out a little cooler on passenger side vent compared to the driver side vent. I just recently changed the expansion valve, granted the evaporator didn't look amazing but I could still see through it and even cleaned it and washed out the fins. The compressor is fairly new, maybe 2 or 3 years. The drier is brand new and the short line coming off of that is new. Whenever I vacuum the system out, the low side gauge doesn't seem to hold the vacuum exactly. It SLOWLY drops. But I vacuumed it out about a week ago and charged it, and when I opened the system today, it seemed like all the refrigerant was still there. I vacuumed it out today after the expansion valve change and added another can of refrigerant. On the can gauge, I brought it up to the highest point right before it would of went into too much refrigerant, but it was still in the "FILLED" range. When I checked the pressure on the High Side, it was 200 psi, about 75-80 deg outside. I cant seem to get it any colder out the vents, and not sure if that is because of maybe an apparent leak or because of the high pressure. Any info or what a step in the right direction would be greatly appreciated. Only thing I can think of, is that there is a blockage somehow in the system, the evaporator is just bad, or the connection in the front line in front of the radiator coming from the drier is leaking. I have opened that up once but I can't remember if I ever really checked the o-ring if there was one.
Thank you for any suggestions on where to begin.
Sorry for the late reply.
@ Freedo, I'm pretty sure we bought the gauges at harbor freight. My dad keeps saying that "shrink and swell" is why the gauge isn't holding steady, yet everywhere I see, people say it should hold steady. Also the sticker on my car says it takes 19 oz. yet one 12 oz can seemed to do the trick. I have a regular filler hose but the latest time i charged it, i tried the filler hose that has the gauge on it, and if I put anymore than the 12 oz it would of been "overfilled" according to that. The can was brand new when I added it so 12 oz.
@ mueller how would a block in the system cause the pressure to drop? Because it builds up pressure against the blockage but slowly leaks past it into the rest of the system? Other than the UV stuff is there a way to check where the leak is? I did the UV stuff maybe 2 years ago, and that stuff is still in the lines, so I'm assuming I would see it if it was because I have checked. I won't be home for a while, maybe 2-3 weeks, so I won't be able to check the pressures vs temp etc.
@ saywhat I'm recovering it.
Based on your comments, there's a refrigerant leak that must be fixed.
But start here:
Charge system by refrigerant weight.
Then, properly measure high and low side pressures with A/C set to max cool, both doors open, and engine rpm held at 1500 rpm in the shade.
Post both ambient temp and temp from center vents.
Also, I forgot to add, the latest time I fooled around with the system I did this. It was't really in the shade, but I added the proper amount of refrigerant, outside was around 75 deg. and I used the infrared thermometer on the vents and they were blowing out 65 deg. air, never got any colder than that. High side pressure was 200 psi, Low side was 35 psi
Doing the test in the shade is crucial because direct sunlight will substantially raise the ambient air temperature and thereby invalidate interpretation of the test results.
If you already have dye in the system, look for areas where the dye has accumulated.
Whenever I vacuum the system out, the low side gauge doesn't seem to hold the vacuum exactly. It SLOWLY drops.
how would a block in the system cause the pressure to drop?
FYI: Losing vacuum means the pressure rises not drops.
Because it builds up pressure against the blockage but slowly leaks past it into the rest of the system?
Because the hypothetical blockage prevents the deep vacuum from removing all air and refrigerant from the blocked section of the A/C system.
Yes sorry I said that backwards about the pressure thing. Yeah I understand being in the shade is important, but the baseline fact is that it isnt blowing cold air, It was in the morning time when the sun wasn't as strong. I can't remember if it was directly heating it. but it was pretty much blowing room temp air and I am trying to solve the issue. Plus I point the laser down the vent, not just on what you see on the dash, I pointed it down in there.
And thank you, I believe there might be a blockage because I've never seen the compressor disengage while A/C button is on, so it is probably deadheading somewhere. The expansion valve was definitely one of the issues, I am not sure if the evaporator is the next issue. Its never been changed.
Thanks
Deschlog: Thanks. I already took the evap out so I know how it goes in and out and all the parts to it, airways looked clean, and cleaned any mouse nesting on the housing etc. Just the evap fins are very brittle and falling off so im thinking not good heat transfer.
Mueller: Ill have to look again. as I said the expansion valve is brand new, installed 2 weeks ago, it definitely helped just didnt fix. The compressor is new as of probably 2 years. There could be moisture in the lines. I was thinking of possibly having a professional vacuum it out and maybe use nitrogen in the system and see the leaks. then I am not wasting refrigerant. or just have them try and chase the leak.
There are too many caveats about the manifold gauge test you did, so I would not try to diagnose with your pressure readings.
My recommendation is that you redo the test in the shade and actually measure ambient temperature. It’s also important to know the relative humidity, which should be available on a weather website.
07-16-2019, 02:07 PM
A/C not blowing cold air
