98 Explorer - A/C Compressor Clutch engaging on/off

I have a 98 Explorer that has a Air Conditioning issue. The clutch
seems to go on and off every few seconds while idling. I have worked
around the issue in the winter time by turning the selector to the
VENT position instead of the other heating options. I can understand
the clutch engaging to perfectly adjust the temperature in the car,
but when it is 30 degrees outside and the air temp inside is around
80, why should it need to engage the compressor clutch? I would
think that there would be some type of hot water regulator going to
the heater box or an air diverter that would mix cool air in. But no,
the clutch will turn on and off and I will notice the RPM drops from
800 down to 650 or so. I am sure this isn't good for fuel economy if
there is extra drag on the engine. I don't know if it is happening
when I am driving or not because I can't tell the difference in the
engine RPM. Anyone have any thoughts on this???

Thanks in advance!
Don C

It's normal for the clutch to cycle on and off when your using any of
the modes except "vent" and floor heat" . This is a design to keep the
compressor lubricated.
The clutch will cycle on and off even when you use your A/C in the
summer.

In cooler weather, the AC is cycled whenever air is blowing on glass to
dehumidify the air and reduce fogging. As another poster mentioned, it also
excersizes the compressor and keeps the oil circulating in the system and
parts lubricated.


"Don-Don" > wrote in message
...
>I have a 98 Explorer that has a Air Conditioning issue. The clutch
> seems to go on and off every few seconds while idling. I have worked
> around the issue in the winter time by turning the selector to the
> VENT position instead of the other heating options. I can understand
> the clutch engaging to perfectly adjust the temperature in the car,
> but when it is 30 degrees outside and the air temp inside is around
> 80, why should it need to engage the compressor clutch? I would
> think that there would be some type of hot water regulator going to
> the heater box or an air diverter that would mix cool air in. But no,
> the clutch will turn on and off and I will notice the RPM drops from
> 800 down to 650 or so. I am sure this isn't good for fuel economy if
> there is extra drag on the engine. I don't know if it is happening
> when I am driving or not because I can't tell the difference in the
> engine RPM. Anyone have any thoughts on this???
>
> Thanks in advance!
> Don C

The clutch seems to be drawing more power than normal from the engine
when it engages. It also seems to engage every 5 seconds or so at 35
degrees outside temp with the heat on full (high) temperature setting.
I would think that the compressor would not need to engage this often
- would it??

On Thu, 23 Dec 2004 19:20:24 GMT, "Jim Warman"
> wrote:

>In cooler weather, the AC is cycled whenever air is blowing on glass to
>dehumidify the air and reduce fogging. As another poster mentioned, it also
>excersizes the compressor and keeps the oil circulating in the system and
>parts lubricated.
>
>
>"Don-Don" > wrote in message
.. .
>>I have a 98 Explorer that has a Air Conditioning issue. The clutch
>> seems to go on and off every few seconds while idling. I have worked
>> around the issue in the winter time by turning the selector to the
>> VENT position instead of the other heating options. I can understand
>> the clutch engaging to perfectly adjust the temperature in the car,
>> but when it is 30 degrees outside and the air temp inside is around
>> 80, why should it need to engage the compressor clutch? I would
>> think that there would be some type of hot water regulator going to
>> the heater box or an air diverter that would mix cool air in. But no,
>> the clutch will turn on and off and I will notice the RPM drops from
>> 800 down to 650 or so. I am sure this isn't good for fuel economy if
>> there is extra drag on the engine. I don't know if it is happening
>> when I am driving or not because I can't tell the difference in the
>> engine RPM. Anyone have any thoughts on this???
>>
>> Thanks in advance!
>> Don C
>

On Wed, 29 Dec 2004 05:56:12 GMT, Don-Don > wrote:

>The clutch seems to be drawing more power than normal from the engine
>when it engages. It also seems to engage every 5 seconds or so at 35
>degrees outside temp with the heat on full (high) temperature setting.
>I would think that the compressor would not need to engage this often
>- would it??

A low refrigerant level can cause the short cycling, but so can, for
example, a bad pressure sensor.
The clutch will usually draw only so much power (current) when it
activates. The AC *compressor* can draw more or less, depending on
several factors.
This is one of those things that is best diagnosed by someone who can
actually place hands on the system, and do the various tests that will
give a correct answer.

BTW, when the cooling system is in thre "heat" position, the AC is
supposed to work.
--
Bill Funk
Change "g" to "a"