Hey guy ... my belt from the ac comp. spins freely.....but when i put the a/c on....the pulley on the compressor turns then stops turns then stops....i put one 12oz. can of 134a...got cold for a minute then it started doing that pulley stoping crap....i need a/c...its so hot in texas...please help!

 

Vaccuum the system out, then recharge. Could be a bad compressor, but I doubt it.

 

You think it may be not enough coolant?

 

Just got the system vaccumed....recharged it with 2 12 oz. cans....there are no leaks....temp is only at 80-82 degrees ....compressor still does the stop and go thing sometimes...after a while of having th AC on....its fresh but not cold!!

 

im going to say your compressor is about to go out.....i had a similar problem on my buddys 2000 ex coupe....

check your electrical connections to the ac comp and check the tightness of the belt...if u have some ac manifold guages, check your pressure, i believe if u have a HIGH low side and a LOW high side, thats a sign of a bad compressor....

 

Well.... looks like I was wrong, change your compressor.

 

well i checked the pressure.....LOW end has low pressure...ad the HIGH end has high pressure...

 

When u vacuumed the system did it hold vacuum at -28 inHG for a few minutes?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nightrider93ex &raquo;</TD></TR><TR><TD CLASS="quote">well i checked the pressure.....LOW end has low pressure...ad the HIGH end has high pressure... </TD></TR></TABLE>

ok so when u checked the pressure your readings told u that you have a low pressure readings on the LOW side and high pressure readings on the HIGH side?

so you have a low-low side and a high-high side, which could indicate a possible plugged accumulator caused by water, dirt, possible orifice tube or thermal expansion valve....

now rather than plugged accumulator, ill have to gues that your civic has a receiver drier as civics dont have accumulators last time i checked.....

 

yea it has a drier.....the temp in the car is at 79-80 degrees....feels alright and fresh but i really want ice cold

 

Can you be more specific with your pressure readings?

1. Did you use a manifold gauge set?
2. What were the exact pressure readings of the high and low side?
3. What was the ambient temperature when you took the pressure readings?

You have a 93 Civic EX with a retrofit to R134a, correct? I just want to be certain that you are not supposed to be using R12 refrigerant as OEM.

When you evacuated the AC system, what means did you use? When you recharged the AC system with refrigerant, did you also instill compressor oil? This would be PAG or POE for R134a retrofitted systems, or mineral oil for R12 systems.

You also stated,
I doubt it is the pulley which is turning then stopping. It would be the compressor clutch. These are different. There exists an air gap, usually from 0.025-0.035 inches, between the compressor clutch and the pulley hub. This gap normally prevents the compressor from pumping because the clutch is not engaged to the pulley. The pulley spins separately from the clutch when the AC is not switched on.

When the clutch coil is energized, it magnetically attracts the clutch to the pulley hub, thus causing the compressor to spin at the speed of the pulley (which itself is spun by the engine). This causes the compressor piston, rotated by the compressor shaft connected to the clutch, to pump the refrigerant throughout the system, thus coooling the vehicle.

Usually, the clutch will cycle on and off when there is a low pressure in the system. This is caused by a low pressure cutoff switch located on the low side of the system, which can be anywhere from the evaporator to the suction inlet of the AC compressor. This switch is normally closed but opens when the pressure in the system falls under a certain level. This prevents compressor damage. AC system's are closed systems; therefore, theoretically, they should remain at consistent low and high-side (not equal, mind you) pressures when running at normal capacity.

In other words, a steadily decreasing pressure while the AC is running would indicate that you have a leak. A leak not only exhausts the supply of refrigerant but also of compressor oil which is carried by the refrigerant throughout the system. Wherever the refrigerant goes, so too goes the oil. The oil is necessary for lubricating the compressor. It doesn't take a big leak to cause compressor damage.

You may also feel along the AC lines.

From your evaporator to your AC compressor should be cold. If it's hot anywhere along there, then it means there is a pressure increase. A pressure increase would indicate an obstruction. The pressure before an obstruction increases, and it decreases after the obstruction. Simply imagine a kinked water hose.

Gay-Lussac's Law (also known as the pressure-temperature law) states that the temperature of a gas is directly proportional to its pressure when the volume remains constant.

And, in closed circuit AC system, the volume in fact remains constant. If you instill 15 oz. of refrigerant and 4 oz. of oil (for example), there should always remain 15 oz. of refrigerant and 4 oz. of oil. That will never increase (such an event is impossible). However, it may decrease, and that is by a leak.

You can feel along the discharge line (from your AC compressor to your condenser) and also along the liquid line (from your condenser to your evaporator/ thermostatic expansion valve). Both should be hot, so be careful. But, if you feel a cold area, it indicates an obstruction. The pressure decreases after the obstruction, and increases before it. If the pressure decreases, so does the temperature, thus causing the line to frost over sometimes or become very cold.

Hope some of this helps. Let me know more information about your problem when you have time. Ultimately, however, if you do not have the proper equipment, I would take it to an ASE certified mechanic. Not that he automatically knows what he's doing, but there is a greater probability.

 

if the clutch cycles on then off on then off, would that also be a sign of a bad ac compressor??????????? i had a similar problem on one of the vehicles i checked, i didnt have time to diagnose it all, but the person vacuumed the system, then recharged it with 2 12 oz cans of r134a, and one 4oz can of ester oil, but it still wouldnt get cold.....i took a quick peak at the ac compressor clutch while the ac was turned on, and the compressor clutch cycled on then off, thats all it did.

i hooked my gauges up and i found that i had a HIGH low side and a LOW high side, which to me could possibly indicate a ac compressor on the verge of going bad........that was my quick assumption as i did not have time to diagnose the whole system.......

i hope the op used retrofit oil when he did the retrofit from r12 to r134a....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MeanGreenMachine &raquo;</TD></TR><TR><TD CLASS="quote">if the clutch cycles on then off on then off, would that also be a sign of a bad ac compressor??????????? i had a similar problem on one of the vehicles i checked, i didnt have time to diagnose it all, but the person vacuumed the system, then recharged it with 2 12 oz cans of r134a, and one 4oz can of ester oil, but it still wouldnt get cold.....i took a quick peak at the ac compressor clutch while the ac was turned on, and the compressor clutch cycled on then off, thats all it did.

i hooked my gauges up and i found that i had a HIGH low side and a LOW high side, which to me could possibly indicate a ac compressor on the verge of going bad........that was my quick assumption as i did not have time to diagnose the whole system.......

i hope the op used retrofit oil when he did the retrofit from r12 to r134a....</TD></TR></TABLE>
Hey MeanGreenMachine,

Personally, I don't trust any person (the one you mentioned in your story), working in a professional capacity (e.g., for a shop and not just doing jobs on the side) who recharges AC systems using the cans and not a charge cylinder and recharging machine.

One cannot get the exact amount of refrigerant into an AC system by means of those refill/ recharge cans sold on the shelf of your local auto store. For example, did this mechanic compensate for the amount of refrigerant that remained in the hose? If your AC system called for 28 ounces of refrigerant, how did this person instill this amount if the cans are 12 ounces of refrigerant each? You know what I mean?

You asked if repetitive clutch cycling can be an indication of a "bad AC compressor." It can. However, internally-damaged compressors usually (not always) emit audible noises which are evidence of the respective damage.

Some vehicles with fixed displacement AC compressors will have a clutch that cycles on and off in order to maintain the pressure within the system and the temperature of the system components (e.g., to avoid an iced evaporator).

In other cases, the clutch may cycle on and off because of a weak clutch coil. Measure the + lead of the clutch coil connector with a DVOM and ensure it is receiving at least 10.8 volts. A clutch may slip if it receives less power than required. A slipping clutch cannot adequately turn the shaft, and a shaft which does not turn adequately cannot reciprocate the pistons. This would cause a low pressure condition within the AC system (bad pump = low pressure). As a result, the clutch will continue to cycle on anf off in order to attempt to compensate for the low pressure caused, originally, by the lack of voltage reaching the clutch coil.

Just some thoughts.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Power of Dreams &raquo;</TD></TR><TR><TD CLASS="quote">
Hey MeanGreenMachine,

Personally, I don't trust any person (the one you mentioned in your story), working in a professional capacity (e.g., for a shop and not just doing jobs on the side) who recharges AC systems using the cans and not a charge cylinder and recharging machine.

One cannot get the exact amount of refrigerant into an AC system by means of those refill/ recharge cans sold on the shelf of your local auto store. For example, did this mechanic compensate for the amount of refrigerant that remained in the hose? If your AC system called for 28 ounces of refrigerant, how did this person instill this amount if the cans are 12 ounces of refrigerant each? You know what I mean?

You asked if repetitive clutch cycling can be an indication of a "bad AC compressor." It can. However, internally-damaged compressors usually (not always) emit audible noises which are evidence of the respective damage.

Some vehicles with fixed displacement AC compressors will have a clutch that cycles on and off in order to maintain the pressure within the system and the temperature of the system components (e.g., to avoid an iced evaporator).

In other cases, the clutch may cycle on and off because of a weak clutch coil. Measure the + lead of the clutch coil connector with a DVOM and ensure it is receiving at least 10.8 volts. A clutch may slip if it receives less power than required. A slipping clutch cannot adequately turn the shaft, and a shaft which does not turn adequately cannot reciprocate the pistons. This would cause a low pressure condition within the AC system (bad pump = low pressure). As a result, the clutch will continue to cycle on anf off in order to attempt to compensate for the low pressure caused, originally, by the lack of voltage reaching the clutch coil.

Just some thoughts.</TD></TR></TABLE>

ill have to get back with the owner of the vehicle that had this ac comp clutch cycle on off issue. its actually a close friend of mine.

ive had good results with using mu snap on vac pump and snap on manifold gauges. i usually put the system under a vacuum using the manifold gauges and the pump. there have been times where i have also used the gauges to fill the ac system. i use the yellow line and hook it up to this squueze type deal that punctures the freon can and then runs through the yellow centerline on my gauges, and then into the ac system. ive also used one of those charge lines u can get at your local auto parts store, one of those lines where u screw on the freon can and hook the other side to the low side and then turn the valve all the way so it will puncture the can and then the freon will flow thru the line and then into the system. trust me if i had the money to get myself a robinair recharge machine, i would, those are nice. ive only used them a few times back in auto tech school.

sometimes you just have to work with what you got...either way lets continue this discussion as i can see from the power of dreamz' replies, he is the authority on the subject ac systems