Serpentine belt hiccup?

MicroBruin · **Posted:** Thu Jan 30, 2014 1:12 am

When my heater or AC is running, I notice that there is a very very slight hiccup at idle, about once every 20-40 seconds I would estimate. I wonder if this is the start of a pulley going bad or something. The serpentine belt has been replaced (a little less than three years ago). Any thoughts on this? I guess I should double-check tomorrow, but I don't think it's just when the AC is on. I believe it's when the heater is on as well....will confirm....

dirtmover · **Posted:** Thu Jan 30, 2014 8:37 am

This will be your compressor cutting in and out.

DOC4444 · **Posted:** Thu Jan 30, 2014 9:35 am

Just to clarify what Dirtmover correctly stated, the AC runs when the heat is on in the floor and combo positions. To avoid running AC in the winter, select the dash vents only or do the mod that disables AC in the heat settings.

DOC

MicroBruin · **Posted:** Thu Jan 30, 2014 3:45 pm

DOC4444 wrote:

Just to clarify what Dirtmover correctly stated, the AC runs when the heat is on in the floor and combo positions. To avoid running AC in the winter, select the dash vents only or do the mod that disables AC in the heat settings.

DOC

Ahhh....this is what perplexed me. If it were only the AC, I would figure it was the compressor. Having it kick on with the heat is what confused me. I believe you are exactly right...the compressor is still running in the floor, defrost, and defrost/floor combo setting. Interesting. It's a very mild hitch or hiccup, so maybe it's perfectly normal, huh? It just seems a little more pronounced than on other vehicles I've had, when their compressors kicked in. I guess it's probably nothing to worry about, unless it becomes more harsh. Thanks for chiming in, guys.

papaindigo · **Posted:** Thu Jan 30, 2014 4:03 pm

I certainly agree with the fact that the compressor kicks in and out in AC mode and some heater modes. That's common practice in more "recent" vehicle design and mentioned in the owner's manual.

What does bother me a tad is I've never noticed any really perceptible impact of that cutting in/out at idle which means either mine doesn't do it or my perception is low. More to the point what can make that cutting in/out more perceptible is the, for lack of a better term, bounce in the serpentine belt caused by the AC compressor clutch kicking in/out. That bounce is supposed to be absorbed by a combination of the alternator clutch and the serpentine belt tensioner. I know of at least one forum member whose perceived AC clutch problems were actually a bad alternator clutch.

Long winded way of saying it might be a good idea to check your alternator clutch. At idle pop the hood; with a light look down the serp belt from the alternator clutch to the serp belt tensioner; if it's barely twitching good if it's bouncing the alternator clutch is shot. Also IIRC that clutch has a plastic cap; if so pop it and look inside for red dust; if lots the clutch is shot.

weeks101 · **Joined:** Mon Jul 30, 2012 3:29 pm **Posts:** 747

DOC4444 wrote:

To avoid running AC in the winter, select the dash vents only or do the mod that disables AC in the heat settings.

dirtmover · **Posted:** Thu Jan 30, 2014 5:06 pm

papaindigo wrote:

What does bother me a tad is I've never noticed any really perceptible impact of that cutting in/out at idle which means either mine doesn't do it or my perception is low.

I think perception plays a big part. I've never really paid much attention to it at idle but I do notice it when driving on the hghway.

WWDiesel · **Posted:** Thu Jan 30, 2014 10:12 pm

DOC4444 wrote:

Just to clarify what Dirtmover correctly stated, the AC runs when the heat is on in the floor and combo positions. To avoid running AC in the winter, select the dash vents only or do the mod that disables AC in the heat settings.

DOC

What about just unplugging the clutch wire on the AC compressor till spring/summer when AC is needed and then plug it back up??? :roll:

Beats taking the dash apart I would think? :wink:

Serpentine belt hiccup?

Who is online