Our 2005 Kia Optima began having an intermittent issue with a belt squeak. Happens just now and then, for a while usually, then goes away. Doesn't seem to fit any particular pattern as to whether the car was just started operating or been operating a while. Sometimes might last for a few blocks of driving, sometimes just short 10 or 20-second periods of time. Always seems to stop though, so far, but rather annoying and concerning, even though it really doesn't do it very often (yet anyway). Pretty sure there's only the one big long serpentine belt, and it "looks" okay. I mentioned it to the mechanic at an auto repair shop, how it is intermittent like that, and how if I was to bring it in it likely would not make the noise then for them to easily diagnose. His suggestion was just to either wait until it starts doing it more often or regularly and then bring it in to be looked at, or that meanwhile I might try taking a wire brush while the belt is running (being careful of course) and sort holding the brush into the grooves of the serpentine belt while spraying a little silicone spray into where the brush and the grooves are touching. He said that might remedy the problem, and if it doesn't to go from there for continued troubleshooting otherwise. Comments? Before I try?

 

Squeaky belt usually means the tension is low. Carry a bar of soap, and when it starts squeaking, CAREFULLY hold the soap against the tapered and inner edges (where it contacts the pulleys) while it's running. If that stops the noise, it probably indicates the belt needs to be tightened up just a little bit.

You can also use an anti-squeal spray, but you're probably going to pay $7-$10 for even a small can, and it's not something you want to keep putting on the belt, as it will build up residue and cause issues in the long term.

 

I'll try the bar of soap trick just mentioned I suppose. I'll bet when the belt starts squeaking, I'll jump out open the hood and by then the squeak will have stopped. thats how it acts,but we'll see, I'll keep that in mind, and try if I can. thanks

my luck this will turn out to be bearings in a pulley, something like that, expensive/extensive to fix

 

I had a Ford van with a serpentine belt that would squeal..... usually more in the damp and wet weather. I carried a lumber crayon. Just a light touch to the ribbed side was all it took and it was quiet for months.

That anti squeal spray is like a shellac and does make a mess.

 

Belt squeak is a different sound from bearings... imagine the squeak of rubbing a balloon, only higher pitched. Bearings will be more of a metallic scraping sound.

If you can, try grabbing a video of it with your phone (assuming you have a phone capable of video recording). Doesn't even need to be high-def, just needs to capture the sound.

 

Yeah this is happening in the damp and wet weather, but that's about the only kind of weather we ever have here in SE Alaska. I'll see if I can snag a lumber crayon somewhere and try that trick. Do I wait until it is actually squeaking to do the light touch onto the belt, or just do it anytime at my convenience? Yeah I'll steer clear of that anti squeal spray. thanks PJmax

 

The lumber crayon trick is essentially the same thing as using a bar of soap, so use whichever is more convenient.

 

Okay well this isn't like a metallic scraping sound, at least. More like what you described per the rubbing balloon pitch (wife says almost sounds like a cat high pitched mewing -- and no, its not a cat so we can just rule that out right now). The only time we've heard it so far is while sitting inside the car, while driving, usually not going too fast, just picking up speed or whatever in the block/neighborhood. So doubt we'd have much luck trying to capture/record the sound from inside the car to be able to post here. It's not all that loud to hear, actually, inside the car, but outside it would be definitely noticeable.

 

Does it get any worse if you turn on things that will load the belt, like A/C?

 

Apparently the car is equipped with A/C but we've never had occasion to use it, and likely will never need to because it's never warm/hot enough here to need A/C (and the car is one we've newly acquired relatively recently so just never even bothered really trying out the A/C). And don't really think there is much of anything else that we could turn on that would cause any more than normal expected load on the belt.

 

Understood... things like turning on lights or the rear defrost or blower fan will put a brief load on the alternator which will load the belt and could cause squeal if it's a hair loose. If it has A/C you could try switching that on just to test.

BTW, in a lot of newer cars, when you put the heater on defrost, it will also engage the A/C, as that dries the air and will clear the window faster.

 

Okay well especially recently we've been needing to use the rear window defrost (not blower type just those heating wires inside the glass). Might try switching on the A/C just to test, as you suggest. And I didn't know that about what you just explained in regard to heater on defrost might also engage A/C. Will keep ya posted. thanks again

 

Try turning on lights, blower and rear defrost all at once, that should put a pretty good load on the alternator.

 

Will do. As I mentioned, we don't have a rear blower of any kind, but just the heat wire stuff inside the rear window glass type. Have a regular heater blower for the front of course, will go ahead and turn that on full blast (along with lights and rear defrost). Will do a little experimentation and get back to ya as per results. fun.

 

Yep, that little wire pulls a lot of current too... most of them I've seen have a 15A fuse, meaning they're probably drawing at least 10A.

 

Update: I checked and then double-checked, and indeed what I discovered was that if I put on the lights, the rear defrost, and the blower fan, I get the squeak/squeal. Then, if I turn off the lights, or turn of the rear defrost, the squeak/squeal stops immediately. So, I suppose, as per quote above, the belt could be a 'hair" loose. I should try to tighten it back up a "hair" then. In fact, if I had a belt tensioner gauge, I could probably even try to tighten up the belt to spec. Don't have one though, and don't particularly wanna hafta buy one either. Any satisfactory alternative "tricks" or tightening "rule of thumb" tension advice for the belt, or would I be "playing with fire" by trying to rely on such tricks so the fancy tightening gauge is highly advisable? any comments appreciated.

 

From this article: How to Change an Alternator on a KIA Optima - Kia Dealers Articles - MerchantCircle

"Mount the accessory drive belt and adjust its tension with the tensioner adjustment bolt. A new belt should have a deflection between 0.22 and 0.31 inches. A used belt should have a deflection between 0.33 and 0.45 inches."

In other words, if you push down on the longest free portion of the belt, it should deflect only about a quarter inch for a new belt, or just under a half inch for a used belt.

This is a "generic" drawing, but it will give you the basic idea.

 

Great. Thanks a bunch Matt Ion. I get it. Won't take much to get gid rid of this pesky belt squeak. Thanks big time for the helpful replies.

 

No worries, hope you get it sorted! I know how annoying a persistent belt squeak can be!