Hey guys it has been a while since I have posted here. Anyways my issue seems to fall back towards my AC not getting as cold as it once was in my 98 Civic LX . I noticed this just the other day when riding in a friends car and was practically freezing and then driving my car I could really feel the difference into comparison of another.

So today I go to Autozone thinking I can do it myself with some A/C Pro. Get the car running and plug up the gauge that comes with the A/C pro and to my surprise it reads at about 45 PSI which was in the green so I didn't add any Freon. I check around the vehicle and this is what I conclude. The compressor cycles on normally on and off, for instance it will cycle on for 5 seconds hitting 45 PSI then cycle off and it will keep repeating itself about 3 times and then will cycle in longer intervals. The high pressure line is extremely hot however the low pressure line is hardly even cold where it honestly just feels like the ambient temperature. Now one thing I did notice while checking the PSI is the my low side stem valve had alittle leak due to it not being tightened down and I am unsure how long that has been like that. Following the low side into fire wall I will place my hand on the evaporator core and even that doesn't feel cold at all. Last year I changed both the evaporator and the expansion valve as well at the temperature sensor after getting it evacuated and then putting the new parts in the shop said they evacuated it again and then recharged it. The condenser fan works and kicks on and the condenser has no damage or bent fins. When I do have the A/C on I can feel an ever so slightly difference in the cabin but not enough to counter the Texas heat

In short my compressor cycles on and off reaching 45 PSI. Evaporator, expansion valve and temperature sensor have been changed last year with proper evacuation and recharge. However following the low pressure line after the condenser it is neither cold or show sings on condensation like most vehicles I have seen and the fan does kick in when turned on. Inside the cabin the evaporator is not even cold and every now and then you can hear the expansion valve do normal hissing sound for a second or 2. The high pressure line valve was slightly leaking due to it not being tighten properly. I also don't ever recall changing out the drier

Is this the sign of a bad condenser or air in my system? I plan on taking it pep boys or so to do one of those $30 A/C diagnostics but I just don't want to be given the run around of having to evacuate the car and replace parts over and over again and recharge it to be something else or something simple I am missing. Thank You!

 

You should not get any cycling until the evaporator is cold enough to have the thermostat turn it off. Rapid "cycling" you're seeing may actually be the high side switch tripping on over-pressure. You can work on it yourself but don't try to without proper tools.

Reasons for excessive high side would be:
condenser fan doesn't work
Overcharged with refrigerant
Overcharged with oil
Air contamination (didn't evacuate before charging)

 

Thank you, I will go grab the set of guages that will tell me my high side pressure

 

Most common problem on Honda Civics is the expansion valve, one of the symptoms is hot high side lines, [compressor is working] and not cold low side lines, [expansion valve not working properly].94

 

Took my car to the shop to get one of those $30 test and after pressure testing and placing uv die in it they showed me where my discharge line (compressor to condenser) had a leak. Had it evacuated so I can go replace line and drier and they said that the machine counted less than an ounce of refrigerant in the system. Going to get it fixed when the parts come in but as a general question how does this cause the a/c to not produce cold air. I do understand I was extremely low on refrigerant but I thought that the compressor would not even try to engage if it was that low? Thanks guys

 

Ac diagnosis

Does the ac fan turn on all the time when the ac button is illuminated? If yes continue down trouble shooting list

Does the compressor clutch engage and spin with thr pulley?

If the compressor is clicking on then off then there is a pressure problem detected by the switch. When taking a pressure reading the gauge shows acceptable pressure before the switch turns off the compressor the switch could be at fault. It pressure readings indicate that pressure is spiking there could be too much freon in the system. If pressure fails to display there is not enough freon in the system

Take a pressure reading on the low side. If compressor is cycling with engaging and disengaging clutch there is an issue with too much pressure if level rises over 50 psi on low side

Is the ac cool and any pressure over 25psi result in the pressure shooting too high and compressor cycling, most likely expansion valve failure

Is the ac pressure good, the compressor and fan function flawlessly, could be drier or system contamination. Evac and recharge system and re diagnose system. If new freon in the system and ac blows cool not cold drier replacement is reccomend ed

 

With only an oz of refrigerant, the compressor should not have run, I think the shop was giving you a story, it may have been low on refrigerant, but not that low, [if compressor was running]

It is also possible the pressure switch is N/G, but still, a hot high side line indicates a fair amount of refrigerant.

Lets see what happens after the repair the R134a charge on your car is 23oz.

ACCUMULATOR/DRIER 1411616 $14
AC HOSE 4811534 $21.15 both at Performance rad.

Are you installing them yourself? 94

 

Picked up a drier already and going to pick up the discharge line(high pressure). I am going to install them myself and then get the system flushed and recharged again. Should I replace the pressure switch just in case?

 

It only takes 50 psi to close the switch, which will be reached with a very small amount of refrigerant.

The saying is that "you get all the cooling from the last 6 oz of refrigerant"-- until you have enough to push all the way around and get the evaporator mostly full of LIQUID refrigerant, it isn't going to cool.

Replacing a leaky part like this does not require flushing. Flushing should be done when the system is dirty, for example after the compressor blows up inside and sheds out bits of metal. Flushing improperly or incompletely will leave residual solvent, which is worse than not flushing at all.

Also don't be tempted to add a bunch of oil. Maybe add 1/2 or 1 oz for the new dry accumulator. Too much oil is bad.

 

Thank for the info. I just picked up the drier right now. So being that it was a leak in the hose I should be ok with getting it vacuumed and recharged without a flush correct? Also when adding oil which port so I add it into for the drier?

 

Also since the vehicle is evacuated already should I go ahead and just replace the expansiom valve?

 

Your first post said new expansion valve installed last year, so you shouldn't need to change it again. It sounds like a case of simply leaking out, so replace the leaky part and go on.

 

Just add the oil to the new filter before installing it. 94

 

Ok guys took it to the shop. Relaxed drier, discharge hose, expansion valve, and drier. System flush and recharge to Honda specs. The temperature only hits 70 degrees out the vents. I don't know what to look for anymore.

 

One thing i did notice is the compressor will stay on because I guess the temperature sensor inside the car says that it hasn't meet the temperature needed. Maybe it is a compressor issue however when i touch the lines they are really cold. Then after the expansion valve they are not as cold but it seems like the evaporator isn't cold enough.

 

Sounds like a defective expansion valve.

What where the high and low side pressures? 94

 

Unfortunately the shop didnt tell me these things.

 

Look at your condenser. If it is not getting proper air flow it will cause the high side to stay high and the compressor to cycle. Mine was packed full of power steering fluid from p.o. Having a leak. My discharge hose was so hot it melted a zip tie that held the wrap on it. Also when the compressor kicked on the engine would fall on its face. I used nu-brite from grainger. It is industrial strength.
My compressor is going out but the Ac is now cold and pressures are in spec.

 

Laymans Ac system check list. To be the technicians check list really all you need to do is verify that all points on the ac system are receiving 12 volts. Ac fan, ac switch, and ac compressor.

Does the condensor fan turn on when the ac button is illuminated? If no then check voltage at the plug for the fan and if reading is 12v replace fan

Does the clutch engage on the compressor when the ac button is illuminated? If the clutch does not try to engage at all try bypassing the pressure switch on the dryer

If jumping the switch does not result in the compressor trying to engage the clutch, check for voltage to the compressor, the red wire. If compressor is receiving 12 volts and not engaging the clutch, the clutch is bad and the compressor needs to be replaced

Does the ac clutch engage and then after a few seconds click off and dis engage? Check your pressure readings, if pressure reads over 45psi on the low side and climbs until the compressor shuts off you could have too much freon in the system or you have a bad expansion valve. Evacuate the system and monitor high side and low side pressure until they are at specified operating levels, or until clutch kicks off

If after evacuation you add less than the specified amount of freon and the pressure in the system spikes to make the compressor switch turn off the clutch you most likely have a bad expansion valve

 

I just noticed that when i turn the ac on the compressor starts to knock. When i took off the relay to be sure the sound went away. I will have to take the belt off and see if there is any play on the compressor

 

It will knock and buck when the clutch engage if there is too much or to little freon in the system

 

Say what??? 94

 

Any "banging" from compressor points to a bad compressor.

I would also find another A/C shop, a 70* vent temp. after service should never have left the shop without an explanation of what was wrong, the gauge pressures will tell you what the problem is, defiantly any "banging" from the compressor should have been mentioned. 94

 

Find out how much oil they added. Too much oil is really bad in a scroll compressor.

You need to start with a set of gauges that can measure both pressures to DIY this.

 

I will take t on Tuesday to get readings of the high and low side pressures. One thing I do notice now is every now and then my new expansion valve makes a loud/whinning whistle sound for a good 5 seconds. Especially when cold starting.