Help me diagnose a noise

Hey guys,

Recently I've been hearing a loud squeal/squeak, as if one of my belts is loose. However, I'm worried it's something more

The squeal is very loud, and it happens most when the engine is cold and I start the car. I will start the car, and then after five seconds, the squeal will start, and will go for a minute or so, and then stop, or I will start driving and the engine noise muffles the squeal.

It almost sounds like there is a rattle involved with the squeal, nothing loud or serious, but it is not just a squeal, more of a extremely rapidly chirping squeal.

The truck is a 99 4wd xtracab sr5. It's got about 135K miles on it, and I'm not sure if the water pump has been replaced, as I bought it at 115K. I don't know if that has any bearing on this.

Any thoughts?

 

definitely sounds like a belt. 1st gens use manual tensioners that either require periodical re-adjustments, or some people just don't know how to properly adjust them. Easiest way is to twist each belt as long as it's not a super short section, you should only be able to twist it about a quarter of a turn or 90 degrees. Seems like the noisy ones are always closer to 180 degrees.

 

are you sure it's in the engine bay? that loud fast chirping part sounds more like the problem myself and plenty few others ive seen on here have had, involving the blower motor underneath the glove box. The fan gets off balance and gets and annoying squeek when not adjusted.

easy way to check is when you start to hear it turn your fan/ac/heater completelly off and check it. Mine starts chirping if i stop at an angle. best of luck!

 

x2 on watch your eyes with spraying anything on the belts. Use safety glasses and keep your hands and clothing out of the way of the belts and fan!

 

Thanks guys, I'll grab a can and (carefully) give it a try

Just an update, I had it in the shop to get inspected, and I asked the shop, and they had no idea.

The noise only happens when the temperature gauge is climbing to mid-level, and only when the truck is idling in gear. It usually starts as I roll to a stop, at the very last second of motion, and then chirps/squeals for a long chunk if not all of the time I am stopped. After the temperature gauge hits mid-level, it does not seem to happen.

Don't know if that changes the diagnosis. It also definitely sounds like a chirp, almost rattle more than a squeal. It is extremely fast and high pitched, so that it sounds like a squeal, but there is a rhythm to it

 

You can also pop off the accessory belts to eliminate it being an issue with that particular belt/pulley/accessory. I would start with the AC belt (bottom passenger side) since that one has the idler pulley which can start squealing. Loosen the tensioner until the belt is loose enough that it won't turn and start it up.