madjap

I have a 95 EX, and the AC really isn't as cold as I think it should be. But then again, I bought a 93 Civic new (back in 93, of course), and the AC really wasn't good on that car either.

I can only get the air down to about 59 degrees at the vent when it is 92-95 degrees outside. In all my other cars, the AC kicks down to about 38-42.

I recently had to evacuate the AC and recharge, due to removing the dash / evap during a wire harness swap. I replaced the filter/drier, but did not do the expansion valve. In retrospect, maybe I should have.

What is the common consensus on this?

TIA


JAP

desync

The ac in my 92 wasn't really all that cold either, but it should still be lower then 59 degrees coming out of the vents.

I checked the FSM and it's useless lol But if you're at those temps, and it's humid, then mid 50's is about right if I can understand the stupid charts right.

Former User

Under what conditions did you measure delivery temp from the vents?

In the service manual, the test is done as follows:




As you can see from the chart below, the delivery temp when it is 95F outside should range from about 60F (at 30% relative humidity) to about 78F (at 80% relative humidity).

madjap

Thanks Ron.

I guess according to that graph, my car is cooling as it should.

I'll live with it. It should start cooling down in a month or so anyways.



Thanks


JAP

Former User

If the way you did your test was different than the test conditions I posted, then you may have an A/C problem. What exactly were the conditions of your test?

AGENT_47

Hmmm I have a 93 SOL and get low to mid 40's in high humidity , I live In Florida (late afternoon yesterday I saw the thermo touch 40 degrees)

In the noon time blazing summer heat my thermo measures at 50 consistently, after a starting temp of 120-130 inside the car

xJDMB16x

My AC stops blowing cold when im in the city with a lot of stop and go but on the freeway it blows really cold does anyone know what could be the probelm... 97 hatch

Former User

Does the condenser fan run?

xJDMB16x

you know what im not sure

madjap

Here are my official findings:

After doing the test to the letter, I got 78 degrees out of the vents at 86 degrees / 68% humidity outside. Not good.

Gauge readings:

Idle: 52 low, 250 high

1500RPM: 35 low, 325 high

I've checked:

Charge level. Correct as far as the amount put in.

Condenser fan, fully operational.

Condenser is clean of any debris.


Ron, what do you think this might be? I'm still pointing towards the expansion valve.


TIA


JAP

Former User

Based on graphs in the service manual and your outside temp and humidity, here are the approximate expected readings:

64F vent output temp (your reading was 78F)
350 PSI high side pressure (your reading was 325 PSI)
42 PSI low side pressure (your reading was 35 PSI)

These comparisons suggest that the refrigerant charge is too low and that more needs to be added to the system.

Duane_in_Japan

350 is way too high, you either have a restriction in the high side, this will depend on where your high side pressure gauge is hooked up, OR, your fan and condensor is not cooling down enough. Again, this will depend on where your gauge is hooked up. Otherwise you have too much freon in the system. Where exaclty is the high side pressure fitting located.

I would want to see the pressures at different periods of time starting from a cold engine, drive in the city, stopping and idling, then go out on the highway. Let us know along the way.

If you get an IR temp gun, the inlet to the outlet of the condensor should drop a good 50 degrees F, if not, the fan is not doing its job or there is a problem with the condensor, such as part of it is clogged up. Spray an equal amount of water all over the condensor front to get it all wet, disable the fan first, turn off the water. Watch the water evaporate from a hot condensor, if you notice an area stay wet longer than other areas, then there is the restriction. Of course water will drip down so the bottom of the condensor will stay wet longer but not much longer. Let us know what you see.

Former User

The chart below from the service manual indicates that ^this statement is wrong:

vitamin_c95

aweseom post and response...gonna check mine too as mine hits about 55 on recirculate on a 100* day with me in it. I thought it was kinda low

Duane_in_Japan

The last bullet of the chart states that further inspection may be required, at 350 PSI, further inspection is always required, lets do some inspecting before we say that 350 is ok because it isnt ok.

You cannot see how dirty the evaperator is without disassebly, you cannot see how much air is in the system without completely recycling the system with a recycle machine or knowing how to service with a vacuum pump and over the counter cans, you cannot measure how much oil is in the system without draining the entire system and refilling with the proper amount in the proper locations. You cannot measure the superheat operation of the expansion valve without special test equipment, I see it was not changed as a precaution nor as recommended MX of disassembly of the complete dash space. Along with some testing I mentioned above.

The chart is nice but its only good in a perfect world, which this car is not in. On a side note with both high pressure on the high and low side, I would think that the expansion valve is working good theoretically, I would lower the amount of gas and monitor vent temps as pressure was released while maintaining 1500 RPM throughout test.

Since you have a gauge set, what are the pressures while doing stop and go city driving with weak cooling, and what are the pressures on the highway with good cooling please. Yes, you have to drive around with the gauges visible from the cabin.

Also, nothing has been mentioned about heater air getting into the mix also to raise vent temps, clamp off the heater core hoses in the engine bay to take that possibility out of the picture. Then there is a possiblility of the hot / cold air door not being fully closed to the cold side. Still lots of work to do but of course the first step is to always deal with the pressure issue.

Former User

Using the OP's posted outside temp and and relative humidity, the chart indicates that 350 PSI on the high side IS within normal range and therefore would NOT require further inspection. Please double check your facts before posting.

The chart is perfectly fine as long as you do the tests exactly as instructed.

mv1luv

mine blows 52 on the driver side vent when its 101 outside, i live in california where it gets hot. i've dumped and recharged 2 or 3 times before i found out my condensor fan and expansion valve were the problem.

Ben Custer

I have swapped out two compressors and my 09 will cool to about 60 when it is 86 out with 51% humidity. I think it used to be cooler. If I take it off max ac it only goes to 70. Any thoughts?

crazyhorse2011

Could be any number of things. We need you to go to autozone and rent their AC gauges and hook them up to both high and low side. Turn the car on, set AC to MAX AC and let the car run for about 10 minutes while you go drink a beer in the house. Come out and report the pressure on each gauge, as well as the temperature outside, and the humidity too (you may have to use a weather app for an approximation)

TomCat39

10 year old thread in the 92-00 section and yer posting about a 2009.....

Thread closed.