Name that engine noise?

[jaysdead40]

I asked about this a couple weeks ago. The replies centered around the belts, but it doesn't sound like any belt problem I've ever experienced.

"When the engine is at low idle I can hear a swishing, whiring, sound from the front motor area. It's noticable even with the hood closed. When the RPM kicks up, AC etc. it's either gone or not noticable. Any of you over achiever, cruiser knowledge types got any ideas. Rig is 93 FZJ80 with 176,000."

Could it be alternator bearings, muffler bearings, or maybe a (jeep herpe) infection from the wifes Liberty.

This sound is driving me nuts and winters coming fast.

HELP, Jay

 

[wfd175]

Before I replaced my worn, dry, cracked belts on everything with OEM at 120K, I had some really odd noises coming from the front of the motor. I could even hear it inside the truck. Now it's quiet as a mouse. If you havn't done it yet, start with the belts, at least then you'll be able to hear the "other noises" better if they are still there. Make sure to use OEM, I worn, dry, craked belts were Gates. They never were as quiet as these OEM's are now.

 

[jaysdead40]

The belts have only been on for 20,000. Thats why I have been thinking else where.

 

[wfd175]

Did you replace with OEM? my Gates belts only lasted about 2 years before I started noticing that they were looking worn and being noisy.

 

[jaysdead40]

Sorry forgot to include that, Toyoty belts, fan clutch, radiator and hoses, all from Dan the Man.

 

[Mars]

x2 on the OEM belts. I just replaced mine, and they are noticably quieter than the aftermarket ones that were on previously.

Fan clutch?

**Edit- beat me to it!**

 

[CJF]

To check if it's the belts:

Spray some wd-40 on them and see if it temporarily stops.

Curtis

 

[RavenTai]

When I bought my truck it had ribbed gates belts, they made a lot of racket, after replacing those with OEM I then could hear a squeaking noise from the AC compressor tensioner pulley bearing. replaced that and all is quiet.

you can hunt down noises with a mechanics stethoscope, if you don't have one you can use a large screwdriver or a wooden dowel, place one end on the suspect part and put your ear to the other end. the old school airline headphones that were just air tubes work also.

if the noise goes away when the compressor kicks in may point to the clutch bearing, this bearing stops turning when the clutch engages.

 

[jaysdead40]

I havn't been able to determin if the noise is gone when the AC cycles, or if the increase in RPM masks the noise.

 

[RavenTai]

well then start checking.

 

[Proven]

I had the guys at "Urban Land Cruisers" track mine down, it was the idler pulley next to my alternator (I'll find out in two weeks after they do all the other stuff it that is truly IT). My noise was constant in gear, out of gear, idle, off idle, or standing parked. The noise would increase in pitch and become louder with throttle. Temperature affected it as well.

Mind you, I had "NAPA" belts when I took it in...the PO had done all the regular maintanance but elected to use non-OEM stuff to do it.

 

[DTAYLOR]

I think you have an idler pulley bearing noise. Mine went and it was as you describe.

To test, remove it completely and tighten the belts.

The belts will tighten without it there.

Let us know.

 

[jaysdead40]

Idler pulley sounds like a good direction to work on. I'll check that and post up the results.

Thanks for the input.

Surprised nobody voted for jeep herpes.

Jay

 

[C6H12O6]

jeep herpes.

 

[Rusty Phillips]

I think you have an idler pulley bearing noise. Mine went and it was as you describe.

To test, remove it completely and tighten the belts.

The belts will tighten without it there.

Let us know.

just be damn carefull with the pipe slipped over the breaker bar that you use to try to loosen that bolt.....


that tiny nipple on the radiator that the little rubber bypass hose goes to costs over $400.....

remove the hose before you start wrenching & protect the nipple somehow

 

[Russ in California]

I had my belts(gates) and ilders(oem) replaced at the same time and ended up with a tinny metal bearing noise up front. Traced it to the new OEM idler and replaced that one with a NEW OEM idler and I get the same noise. Mechanic removed old idler(new old) and tightened the belt and no noise. Installed new(new) oem idler and noise. He even removed the black shields and that reduces noise just a bit. Took it by a different shop just for a different ear, the owner is a neighbour and a good guy, and with his stethoscope, just as I had done with mine, pinpointed the idler next to the alternator. It sounds rough and nasty.
This is unusual for two OEM idlers to be bad out of the box. Never had that happen before.

 

[ginericLC]

Mine had a similar sound and I had a leaky PAIR valve. You might look at that too.