Engine Size: 4.2L
Refrigerant Type: R134a
Ambient Temp: 85
Pressure Low: 32
Pressure High: 180
A few weeks ago I was having squealing noises on startup, I thought it was the fan clutch as it seemed week even with a warm engine. So I replaced the fan clutch and belt, and since the truck has close to 200k miles I also replaced the tensioner and pulley, idler pulley, hoses, thermostat and water pump. The A/C was not working well last summer so I removed the radiator flushed it and cleaned the condenser while doing the other work. When I was replacing the belt I tried turning all of the accessories by hand and all felt smooth.
Well you can imagine I was not happy when the squealing returned a few days later - although now it is much quieter. I usually only hear it at start up and idle when the engine is cold. Also my A/C wasn't working, I found that the clutch wasn't kicking in and I thought it was due to a low static pressure (wasn't sure how much static pressure was needed to allow it to run) so I added a can of refrigerant but it still didn't kick on. I also tried to jump the low pressure switch but the compressor still wouldn't kick on, so I tapped the clutch with the handle from a hammer and it kicked on and cooled ok. I then tried turning it on and off several times and it kicked on each time. However it's been intermittent again ever since.
Now I'm wondering if the A/C clutch might be the cause of the squealing noise. When I searched the Ford forums for "squealing belt" I found a number of topics that claimed that the compressor clutch was the cause of their squealing belts. Is this a common problem with the fs10 of just a misconception?
Sounds like either the compressor and or clutch is on it's last leg. I would be sure you don't have a pressure issue when the belt slippage occurs.
Thanks for the response.
Interestingly I don't think it's made any noise when the compressor is engaged, it was mostly happening a few weeks ago while it was still cool enough that I wasn't trying to use the air. When these compressors go do they tend to grenade?
How long can a compressor go? I want to just change the clutch to avoid opening the system, do you think it's worth it with 200k miles to try just the clutch or would you recommend a new compressor?
First check your clutch gap.
Yes- pull a shim out from behind the clutch- pull off clutch- be careful- count shims, then make it so the clutch gap is near 0.020" -- yours is probably near 0.050" or so-- then go from there-- belt squeal when engine cold is usually just the load of the alternator on the engine- no big deal-- can be a sign of a weak tensioner- or a bad tensioner by design if yours is new...
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......
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