Hey, I’m seeking advice on a potential issue with my jeep. Everytime I crank it up there’s a loud whistle initially for about 30 seconds and then get quieter, but doesn’t go away. Is there a belt that needs to be changed or tightened?
Loud sound on startup on 1994 YJ
- Thread starter lavstin12
- Start date
Flyer58
YJ Addict
Sounds like a worn or loose fan belt. They can squeal very loudly . There are spray on products like Belt Grip that may temporarily help but usually don't last long.
Is it a “whistle” or a “squeal?” Belt squeal is pretty distinctive and recognizable to anyone who grew up in the 80’s.
Whistle is air moving rapidly over a small gap; e.g. throttle body, intake leak.
Could also be a bad bearing on one of the belt pulleys, usually the idler.
Post a short video/audio clip if you can.
Try spraying a little water on the belt when it’s running as in this video. If the squeal gets louder then the belt is loose. If the chirp goes away it’s a problem with one of the pulleys. (Keep hands hair clothing jewelry out of the way of the belt and fan blades.)
Whistle is air moving rapidly over a small gap; e.g. throttle body, intake leak.
Could also be a bad bearing on one of the belt pulleys, usually the idler.
Post a short video/audio clip if you can.
Try spraying a little water on the belt when it’s running as in this video. If the squeal gets louder then the belt is loose. If the chirp goes away it’s a problem with one of the pulleys. (Keep hands hair clothing jewelry out of the way of the belt and fan blades.)
Gilaguy23
YJ Addict
When you fire up your jeep the alternator is working double time to recharge your battery. Thats possibly the squeal you hear. If it never goes away then like the guys said start checking for bad parts like the PS pump, water pump etc. The belt should be flexible at a point between pulleys, say 1/2 to 3/4" total in/out with some force. Should not be sloppy or easily moved around.
Flyer58
YJ Addict
This is crazy, it's like my YJ reads this forum and starts having issues that arise in here.
I recently didn't a bunch of work but nothing around the belt or pullies other than the alternator wires on the back side and radiator in front. Added new coolant and burped the system, ran it for 15 minutes or so, all was good.
The next day I start it and the belt squealed like crazy. Hasn't done that in years and was continuous loud squeal. Spritzed it with a little water and it immediately went silent for about 30 seconds before starting up again. Most likely a pully out of alignment. In fact I could see the belt was not straight coming off the pump.
I checked with a flat bar between the alternator and the crankshaft pulley and they aligned ok, then checked between the power steering pump and alternator and there was a huge difference. Close to 1/4 inch off with the pump pulley too far forward. Same for the Crank pulley to the pump., again pump pulley too far forward.
I did change the pump pulley two years ago because the old one was cracked. I hope the new one isn't walking off the shaft since it's pressed on. It does look like I can press it on a little more to take up the difference.
I recently didn't a bunch of work but nothing around the belt or pullies other than the alternator wires on the back side and radiator in front. Added new coolant and burped the system, ran it for 15 minutes or so, all was good.
The next day I start it and the belt squealed like crazy. Hasn't done that in years and was continuous loud squeal. Spritzed it with a little water and it immediately went silent for about 30 seconds before starting up again. Most likely a pully out of alignment. In fact I could see the belt was not straight coming off the pump.
I checked with a flat bar between the alternator and the crankshaft pulley and they aligned ok, then checked between the power steering pump and alternator and there was a huge difference. Close to 1/4 inch off with the pump pulley too far forward. Same for the Crank pulley to the pump., again pump pulley too far forward.
I did change the pump pulley two years ago because the old one was cracked. I hope the new one isn't walking off the shaft since it's pressed on. It does look like I can press it on a little more to take up the difference.