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Too Low Vent Temp??

73Wagoneer on Tue February 24, 2009 6:10 PM User is offline

Year: 94
Make: Honda
Model: Civic
Engine Size: 1.5
Refrigerant Type: 134
Ambient Temp: 85
Pressure Low: 20
Pressure High: 200

Im in El Paso, TX, It got up to 85 today so I figure Id see how the a/c is working in the wifes car, I had vent temps of 50, with fan on high, it felt like it didn't really cool the car down, so I got home and put the guages on it. what are your thoughts and am I just being to picky?? I did replaced the evap and desicant cartrigde, end of last summer, and thought it was much cooler then.


TRB on Tue February 24, 2009 8:57 PM User is offlineView users profile

Pressure listed at idle or 1500 rpm?


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73Wagoneer on Tue February 24, 2009 10:14 PM User is offline

1500 rpm

chris142 on Tue February 24, 2009 11:42 PM User is offline

I assume that your saying that you were not happy with the 50*. Thinking that it was too warm?

The 1st thing you need to do on a Honda is make sure that the heater valve is shutting all the hot water to the heater off. Feel the hoses.

Chick on Wed February 25, 2009 7:35 AM User is offlineView users profile

50 on high fan isn't that bad, the air isn't staying over the coil long.. Try lower fan settings, and it is possible you have a leak, the only way to know if your system is fully charged is to recover and weigh it, and then recharge into a vacuum the factory amount. It is actually quicker than chasing ghosts.. Once you know you have the proper charge in there, you can diagnose the system better..Hope this helps..
BTW make sure the condenser fan is running, the condenser clean of dirt and leaves etc.. You do need a clean free air flow....

Email: Chick


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JACK ADAMS on Wed February 25, 2009 3:12 PM User is offline

Would also check for leaks in the system.... This application is known for leaking shaft seals.

TRB on Wed February 25, 2009 4:08 PM User is offlineView users profile

Pressures look in line with the performance chart for that ambient. Checking the hot water shut off is not a bad idea. But 50 on high blower is not that bad. Drop in down to low blower and post the results.


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mk378 on Wed February 25, 2009 5:57 PM User is offline

The water valve is an extremely common problem on those. It needs to be readjusted after a few years.

My Civic, which seemed to be working properly, did not make 50 at idle but it should readily go down to near 40 when cruising.

73Wagoneer on Wed February 25, 2009 8:31 PM User is offline

Wow, thanks for all the replies and ideas, I am the original owner, and I have never checked the hot water valve so checking the hot water valve sounds like an easy/fast first start.

Chris, I was really not happy with 50, because I remember in the middle of last summer (100 degrees) I was getting 40 degree temps, and after driving my 96 Dodge Dakota today I was getting 40 degree vent temps. (outside temp today was 83)

Chick, I will try the lower blowing settings, I have no way of recover and weighing here at the house, I put the charge in last summer when I put a new evap and desicant cart in, I am sure it was blowing colder than 50 then when it was over a 100 outside, so if it is not the hot water valve I am suspecting small leak (uggghhhhh).

Thanks for all the suggestions

Edited: Wed February 25, 2009 at 8:32 PM by 73Wagoneer

73Wagoneer on Wed February 25, 2009 8:56 PM User is offline

Just got back from the garage, well, its not the hot water valve I took the wire off when control was on cold and cold not move the valve any further.

I started the car up, at 1500 rpm, and on the blower on the middle setting the a/c was cycling on at 57 and cycling off at 50, I suspect a small leak, and low on refrigerant.

I will go and pay some $$ to get it recovered to find out how much 134 is in there, the capacity is 17-19 oz, I remember last summer when I charged it, I put a full can in 12oz pulling from a vacuum then started on another can until I got cold vents temps, making sure I did not add more than 1/2 of the second can by comparing that with the weight of a full can. I know this is not the best way to do it, but has worked for me in the past. I suspect because I could not get the exact amount of refrigerant in, and the lose of refrigerant through bleeding the guage lines, I might have been at 17 oz or under and with a very small leak it is just not enough to cool it further.

When I get it home I will pull a vacuum and let it sit overnight.

Thanks again for all the sugguestions


Edited: Wed February 25, 2009 at 8:59 PM by 73Wagoneer

mk378 on Thu February 26, 2009 10:10 AM User is offline

You have the compressor cycling on and off? The compressor only cycles off for 3 reasons: evaporator temperature (the only one that should happen in normal operation), over/under pressure from the trinary switch on the high side, and stall prevention-- abnormally low idle rpm will drop out compressor.

If it's not reheating, it sounds like your evaporator temperature control could be out of spec. Once it starts to cycle the compressor on evaporator temperature, it has decided the evaporator is as cold as it should get. Changing the charge amount, etc. would not improve cooling. Better performance of the refrigerant system will just make it cycle off more.

Generally when a TXV system is somewhat undercharged, the compressor will come on and stay on, but the vent temps will be too high.

Also I'm pretty sure on a '94 model the condenser fan will cycle on and off with the compressor if it's the temperature control doing it; in case of over/under pressure or stall prevent the condenser fan will stay on steady.

Edited: Thu February 26, 2009 at 10:12 AM by mk378

JACK ADAMS on Thu February 26, 2009 10:15 AM User is offline

Have them check the shaft seal real good. We use a shower cap to cove the front of the compressor. This will help keep any refrigerant that may have seeped in this area wile leak checking. Shaft seals can take up to 24hrs to start leaking and then seal it self up.

Good luck....

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