Squealing with heat on defrost

[Brenneman2385]

Hello All,

I have been searching and can not seem to find any answer. I have an 08 XLT EL, that has recently started squealing sounding like the power steering pump going bad. Today I was taking some more time trying to diagnose it, and I found the oddest thing that I can not understand. It seems to be happening when a compressor i presume is turning on, and then it will kick off and stop squealing. I then found it is isolated to the front defrost in some manner. When the squealing starts if I turn the heat completely off, it also stops almost instantly. The same happens if I have it on window defrost, or blended defrost, and change it to feet. It seems to only start this noise with the defrost selected. Does anyone have any ideas as to what this could be???


Thank you,

 

[Ghostwolf]

The AC clutch engages the compressor when you turn on the defroster. I see you’re in the Midwest, so it makes sense that during the winter the only time the AC runs is for the defroster.

The sound I heard in your video sounded more like a whine than a squeal. I don’t think it’s the AC clutch or the serpentine belt slipping or the sound would be more shrill. It sounded more like a bearing to me. The AC compressor bearings would be the primary suspect.

Having said that, the additional resistance of the engaged AC compressor adds a bit of side loading to everything the serpentine belt drives, so it’s not automatically the AC Compressor bearings.

Anyway, my 2¢.

 

[Shantheman73]

The AC clutch engages the compressor when you turn on the defroster. I see you’re in the Midwest, so it makes sense that during the winter the only time the AC runs is for the defroster.

The sound I heard in your video sounded more like a whine than a squeal. I don’t think it’s the AC clutch or the serpentine belt slipping or the sound would be more shrill. It sounded more like a bearing to me. The AC compressor bearings would be the primary suspect.

Having said that, the additional resistance of the engaged AC compressor adds a bit of side loading to everything the serpentine belt drives, so it’s not automatically the AC Compressor bearings.

Anyway, my 2¢.

Holy crap I just logged on here to ask about the same exact thing.

2007 Limited. I’ve been hearing intermittent squealing or whining...and a constant sound like ball bearings going bad.
I squirted some wd40 on a few of the pulleys and behold...the a/c compressor got quiet for a min and then went back to the bad ball bearing sound.

Wouldn’t they normally replace the whole compressor? What’s something like that cost anyway?


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[bobmbx]

Hello All,

I have been searching and can not seem to find any answer. I have an 08 XLT EL, that has recently started squealing sounding like the power steering pump going bad. Today I was taking some more time trying to diagnose it, and I found the oddest thing that I can not understand. It seems to be happening when a compressor i presume is turning on, and then it will kick off and stop squealing. I then found it is isolated to the front defrost in some manner. When the squealing starts if I turn the heat completely off, it also stops almost instantly. The same happens if I have it on window defrost, or blended defrost, and change it to feet. It seems to only start this noise with the defrost selected. Does anyone have any ideas as to what this could be???


Thank you,

I'd check the idler and tension pulleys. In my experience, they fail first. And luckily, they're relatively cheap and easy to replace.