Squeaking belts or pulleys under hood

My car just started squeaking under the hood. I have a '94 Le Baron Convertiible, about 49K miles. The sound seems to be coming from one of the belts or pulleys, probably the widest belt or one of the pulleys it’s on. The alternator is on this belt, but it doesn’t seem to be the source of the noise.

Car was OK Friday. Saturday, I was driving in a downpour and hit a puddle, maybe 6 inches deep, that sprayed a lot of water. On Monday morning (yesterday for the calendar impaired), it was squeaking really badly, especially at idle. When accelerating, the squeak would go away. This morning, the squeaks are quieter, but still there.

Any ideas on the probable cause of the squeak, apart from hitting the puddle (water still under the belts? Rust developed on a pulley?)? Is there something I should do, maybe oil the pulleys? Is there a special kind of oil I should use? Or will it just go away on its own over the next few days?

Let’s get this where you intended it to begin with.

your humble TubaDiva

Almost always the problem is a loose or deteriorated drive belt. If it’s loose, it makes sense to adjust it, if adjustable, or replace the automatic tensioner, if so equipped. If it’s making noise and not loose, the cure is to replace the belt(s). Moisture typically aggravates a worn belt’s tendency to squeak or squeal, but will not affect a belt in good condition with proper tension.

There is a possibility that the noise may be coming from a pulley, but it’s doubtful in this case because that is usually not affected by moisture. Nevertheless, it’s easy enough to check the pulleys while the belt is removed. Another quick test is to apply a quick squirt of WD-40 to the inside surface of the belt in question while it’s making noise. If the noise stops, it’s the belt (the noise will return, as this is not a fix, just a way to temporarily alleviate the symptom).

DO NOT put oil on the pulleys. The last thing you need there is less friction between it and the belt. Perhaps the belts are old and glazed and are starting to slip. If it’s just ordinary V belts which are inexpensive and simple to replace you may have solved the problem. When you have the belts off make sure that each driven device rotates freely by hand and that there is no wobble or play in the pulleys. Pay particular attention to the water pump as this tends to be a mid life failure item.

The belt on my Honda does this during wet weather and it’s most annoying. There’s nothing wrong with the belt or the tension on mine; it’s just how the thing is made. I took it in and they lubed the belt with something from a tube which stopped the squeal.

Although make sure you don’t mistake the crank shaft pulley for a “driven device,” it may be hard to rotate by hand. :slight_smile:

An 11-year old belt should be changed. Esp if squeaking.

You need to send away for Charles Atlas’ course ASAP. :stuck_out_tongue:

      • Squeaking belts is OK for a bit if they get wet suddenly, but if it continues that means old belts or a failing tension-idler (on cars that have them, this is a spring-tensioned arm with a free-spinning pulley on it that keeps the belt tension correct).
  • Lots of times the belts just squeak at low engine speeds but not high, and so people think it’s a minor noisy annoyance but it’s not–you’ll get a belt-related failure eventually if you don’t fix the problem.

That probably wasn’t a lubricating compound they put on there, but rather something sticky—usually called “belt dressing”— to increase friction. Spraying that stuff on a belt can make a sticky mess under your hood. And make sure you’re wearing old clothes if you try to apply it. Lots of it gets thrown off.

Belt Dressing

Thanks everyone.

Now that I think about it, I did get at least one belt replaced five or six years ago, and I think it had to be the one that’s squeaking now. It tore along its length, and I had only 2/3 of a belt for a while, so I think it must have been the wide belt. I’ll have to look through my receipts to double check this and see if I had them all replaced at that time.

Is the consensus here that I’m OK if it goes away on its own, but to get it fixed if the squeaking continues?

Hey UncleBeer I notice that Belt Dressing is “food grade” :cool:. Can I use it on a salad? Does it make a good dip?

Yup. It might even be even kosher.

I believe the Kosher stuff is only available at Murray’s Discount Auto Stores. “What, parts you can’t find? Parts, we got!”

I think they carry those car-door mezuzahs, too.