ac compressor cycling

[JungloSonic]

My ac compressor cycles on/off every 10 seconds or so when the fan is on 1,2, or 3. When I turn it to 4 it stays on for minutes.
10 sec seems extremely low. Can someone with a 1.8L please check for me if theirs does the same..then I can assume it is normal.

Thanks so much.

 

[ozonetrooper]

There are several articles on ac issues here, do a site search for them.

I'm guessing it is low on refrigerant.

 

[JungloSonic]

I don't think it is low refrigerant. I have had a leaking hose replaced and system refilled.

 

[ozonetrooper]

The only way to tell if it is low on refrigerant is to check it. Assuming it is not low because a leak was repaired is not the way to trouble shoot it.

Verify the work that was done is not the problem and then ask what else can be wrong.

When the a/c is called for the compressor should run until it is turned off, unless it has something telling it not to run. There are several things that can do this, low refrigerant is one of them.

When checking the refrigerant level make sure the RPM of the motor is high, simulating driving down the road, and then let the motor idle and the level should stay close to the same in both situations.

If it goes down when the car is idling, it can go low enough to trip a low pressure condition, causing the compressor to stop.

Also make sure the high pressure is not excessive, both readings are dependent on the pressure and temperature of the refrigerant. A high temperature can cause errors in readings. This can be caused by the fans on the radiator not running correctly.

Start with the easy one, check the refrigerant, first.

 

[JungloSonic]

I don't get why the compressor keeps running normally when I set the fan speed in the cabin to high (4).
If coolant was low, then wouldn't the compressor cycles rapidly at (4) fan speed too (this I find baffling)
When ac is on, the radiator fan goes on and off ..Is it suppose to cycle?

Does it have one or 2 pressure sensors? I think there is one next to compressor on high pressure line. Would the check engine light go on is the pressure sensor was defective?

I don't currently have ac pressure gauge but may have to buy one..

 

[JungloSonic]

If coolant is low, If I rev the engine and turn ac on , would the interval that compressor is on increase slightly?

 

[ozonetrooper]

My ac compressor cycles on/off every 10 seconds or so when the fan is on 1,2, or 3. When I turn it to 4 it stays on for minutes.

When the a/c is called for the compressor should run until it is turned off, unless it has something telling it not to run.

I am not certain, but most vehicles run the compressor all the time it is calling for cold air. When you turn up the thermostat on the air temperature it does not cycle the compressor off like a house unit, it only opens up a heat damper to introduce warm air into the mix.

As long as the a/c is calling for cold air the compressor should run without shutting off until the a/c is turned off.

Cycling of the compressor is an indication of an issue with the run call for cold air, the blower settings should not have any control over the run time of the compressor.

 

[ozonetrooper]

I just noticed you are the one with the relay question, if the fan(s) do not come on this is one reason the compressor does not run ...

 

[JungloSonic]

I the fan seems to run when temp hits 106 degrees celcius. I believe this is low speed fan. The high speed fan I believe is suppose to come on at 115 degrees celcius but I don't think it gets that hot.

When ac is on the fan cycles on and off. Is it suppose to do that when ac is on or stay on all the time?

 

[ozonetrooper]

The temperature sensor regulates the on/off of the fan.

Sounds like it is working properly.

 

[JungloSonic]

Yes the fan is working based on ECT temp of 106..but when the a/c or defrost is on and ECT is below the 106 threshold, the fan cycles every few seconds..I don't think that is normal ?