adamdrives

Hey, my name is Adam and this is my first post here. I've had my 97 civic for about 4 years now. It's high mileage, 220k, but I've put a decent amount of work into it to keep it up to speed. It's a good car to get around in and gets awesome mpgs. It's the five speed, no PS, etc.

Recently, the original honda compressor died. It had worked great up to that point, putting air out at around 40 degrees. It was almost too cold, I never had the fans above speed 2. Immediately after it died I replaced it with a brand new compressor, expansion valve, high/low pressure switch (also called binary switch, located on the receiver/drier) and the receiver/drier. Since then I have had nothing but issues.

After I had the system bled and installed all the new parts, I took it to a local shop (I'm visiting my sister in FL and not familiar with any mechanics here. Normally I go to my dad's shop in NY) to fill it up. I was expecting my new AC to blow ice cold. That was not the case. the compressor cycled on and off like crazy at idle, and was hardly better at speed. I didn't use it because I was afraid the clutch would wear out. The guy said it could be the spacing on the AC clutch, I dug around and found out the clearance should be about 0.02". I wasn't able to find a definitive source, just relying on references from forums. I measured the clearance in my compressor and it was closer to 0.04". I took the clutch plate off and removed a 0.02 shim, so that the clearance was now correct. It seemed to function better, but would still cycle like crazy after coming to idle after being at speed. I took it to get a second opinion, since this was going nowhere. The Firestone down the road was having an AC diagnostic special for $10, so I figured what the heck. Let them look at it. 15 mins later, the tech came out and told me the system was overcharged. They took about a pound of freon out of the system. The relief valve on the compressor had also blown, shooting freon and oil all over the block and cat. I don't know how I didn't notice that. Anyway, that was why the compressor was not working properly. Now it ran smooth and constant.

Only problem was, the system didn't get much cooler than 60 degrees. The guys said that I should replace the condensor, since the fins were starting to break (it is original) but said everything else checked out (good high/low pressure, etc). Here's my problem with that: before all this happened, on my original compressor, original drier, original expansion valve, etc, the AC worked great. This was less than two weeks ago. Now, with all new parts, fresh freon and oil, it hardly blows lower than 70 degrees in the sun. (It hit 60 once). It's hot in Florida, but still. Something ain't right. I'm pretty much at the end of my rope with this one. Chances are the condensor is not working as well as a new unit, but I don't see how it would deteriorate so quickly. Can anybody school me? I appreciate. Sorry for long post, I wanted to make sure I got all the details.

TL;DR AC system blows 65 deg air after full overhaul.

ezone

Why didn't you return to Firestone as soon as you figured out it still didn't cool worth a darn? You paid them to figure it ALL out, right?


What was the exact nature of the failure?

What sort of compressor was installed?



Make sure the heater water valve was not disconnected and its lever still moves when you change temps from cold to hot to cold.


What are the high side and low side pressure readings at idle, and at 2000 RPM? Also note your ambient temp and a rough guess of your humidity.

adamdrives

When I returned to Firestone, they reiterated that the condensor didn't look good and that was what they recommended I do next. I suppose I could have pushed for more, but this was near the end of the day and I was tired from running around. Plus, they solved the issue I came in for--the system was overcharged--so I didn't have much leverage. As far as they were concerned, I brought in a car with issues, and they fixed what I paid them too. (AC diagnostic). Since the readings looked good and the condensor looked old (it's original) that was what they suggested.

The old compressor started to get noisy and I suspected it was the bearings. I got over ambitious and decided to try to rebuild the compressor. Once I got it out I realized that it would make more sense to replace the aging compressor with something new rather than try to replace any bearings and seals. I got a TCW compressor off of Amazon. I checked the heater valve and it is entirely shut. I don't have a proper manifold gauge to get readings. Tomorrow I am going to get one.

I've also looked at the chart that goes along with the performance test (page 22-24/5 in the manual) and I am having a hard time interpreting it. Tomorrow I will post back with H/L sides and temp/humidity. I'm visiting family in FL at the moment and it is very humid and warm.

ezone

What did you do about OIL in the ac system at this point?
Did the new compressor come pre loaded with oil?
Did the new compressor arrive empty of oil?
Did you add oil to the system? How much oil?
Correct type of oil?
Did your cans of refrigerant contain oil too? How much was used?


Here's a thought: While it's running, spray water through the front of the car (grille area) to soak the condenser. See if that brings the vent temp down.

ezone

For laughs, this is a condensor I took out of a Honda Fit with about 250,000 miles on it.. The damaged area was all you could see through the opening in the bumper

adamdrives

I believe it came with oil. I wish I could say 100%. The ports were both blocked off out of the box, and there was some oil visible when I took them off. I assumed it had oil, but I did not thoroughly check. I did not personally add oil or freon. I had the system evacuated and recharged at a local shop. I believe it has an automated procedure for adding oil. Interesting about the condensor. I will try that.

adamdrives

My condensor doesn't look great, but it doesn't have damage like that. Some of the fins are starting to flake off on the top, but there is no real "damage"

ezone

I ask about system operating pressures and system oil, because too much oil can cause the system to act overcharged due to reduced internal capacity.

The entire AC system is supposed to hold something like 4-5 ounces of oil, and it's easy to get way too much without knowing it. (I did not look up the actual specs)

Lack of oil can cause the compressor to wear rapidly.
If the compressor overheats and wears, the teflon seals melt and can clog up the condensor.

System pressures can tell one a whole lot about what is happening inside, or at least allow one to evaluate possibilities logically.

adamdrives

I have the results from the gauge: @ 86F and 76% humidity, low side 38psi, high side 225. According to the honda service manual, that seems low for the high side.

adamdrives

Update: I followed the directions more carefully (held at 1500 rpms for ten minutes) and got the following results: At 85 deg F and 75% humidity, the interior vent thermometer read 76 deg F, high and low side 285-290 and 19 psi. This would indicate both the low and high sides are too low, which according to the service manual means clogged or kinked lines.

ezone

Using 76 vent temp, 85 ambient, 85 at the blower intake, and 75 humidity.....and 19/290 for pressures I plugged these numbers into the ac performance application


Low side is low, high side might be ok.


expected low range 28-50
high range 285-325

Possible clogged blower intake (leaves and debris)
Possible moisture in the system causing expansion valve to freeze internally (was the system evacuated thoroughly before charging?)
Possible expansion valve problem (or clogged/restricted lines)


Figure out where all the lines of the AC system are. Run the system, feel the lines for temperature.
The discharge line from the compressor to the condensor should be screaming freekin' hot.
The line out the bottom of the condensor should be 20-50 degrees cooler than the other line (assuming the condensor fan is running).
The lines going in and out of the rceiver-drier bottle should be about equal temperature.

Then at the firewall where the AC lines go through, the small line (high side) should be as hot as it was at the receiver-drier, and the large line (low side) should be COLD if the system is doing its job.



If you have a huge temp difference between inlet and outlet of the condensor then it may be restricted.
If you have a huge temp difference between the 2 lines on the drier, it may be clogged.

adamdrives

Great, thanks for the info. Where is the blower intake located? Under the shroud? When I took the evaporator out there was a fair amount of debris/leaves in it.

The system was evacuated before it was recharged. The discharge line is very hot, so that's good. The drier is new, but I will check the lines. I'm not sure about the high side, but the low side at the firewall is cool (I can see condensation on it).

ezone

Usually in the wiper cowl panel under the windshield.
How cold is it? (anything cooler than dew point will collect condensation)
Is it just a little cooler than your vent temperature, or is it a hell of a lot colder than the vent temperature?



CSB:
I had an 8th gen Civic in the shop the other day, the low side line coming out of the firewall was good and cold like 40* but vent temp was in the low 60s. (THIS was the big clue, the AC on this one was doing its job right and the evaporator core had to be cold)
Found the temperature blend door was not moving to full cold position....pushed on the linkage and the vent temp dropped a good 15 degrees. The car has had mice in it, customer did not want to get into pulling the dash to check for debris inside the heater case.


Yours probably won't be this easy to figure out though.
Was your expansion valve factory or aftermarket?

adamdrives

I'm not sure what you mean by the temperature blend door, but I checked the actuation of the recirc/fresh air vent and it works properly. From inside the car, the interior of the blower motor looks clean.

ezone

The flap inside the HVAC case that is connected to the temperature control on the dash (slide and cable type or dial and servo) is generally known as the "blend door".
Your car also has a cable attached to the blend door operating linkage that goes outside through the firewall to the water valve, to shut off flow of hot antifreeze through the heater core when set to cold.

adamdrives

Oh, okay. Yes, the valve shuts properly.