Topic: Squealing 97 Wrangler

[Drummer Abe]

I have a '97 Wrangler that's developed a weird squeal at certain RPM ranges.  It will squeal once at around 1800, quit, squeal again around 2100, quit, and again at 2500.  It will do this in and out of gear, and is really annoying when going down the road.  I've checked the belt, and it's fine.  I also checked the intake manifold bolts, and they're all tight.  Any ideas of what this could be?  It does seem to be coming from the rear of the engine, if that helps....

[JeepersCreepers]

Have you checked out things like the alternator, idler pulleys? Maybe the throw out bearing?................... :D

[Drummer Abe]

I have checked the idler and alternator, and it doesn't appear to be coming from them.  I changed the water pump a couple of months ago, so I don't think that's the problem.  To me, it sounds like it's coming from the driver's side of the engine, and towards the back / bottom.

[YJmechanic]

kinda sounds like a throught out bearing

[JeepersCreepers]

kinda sounds like a throught out bearing

YEP................ :!:

[chrisfranklin]

Had a unknown squeal-type problem with my 94 YJ which went on for about 9 months starting at the beginning of 06.  Was hugely and annoyingly noticeable at idle; exhaust noise may have masked it as revs climbed. But, urban driving in this Jeep was a nightmare until the problem was found last month.

Originally thought it was coming from the intake area, which, in the end, wasn't too far off.  Looked at the 4.0 TB I had as the cause of the noise - no deal.  Swapped out the Spacer for one with no swirly deal - nope.  Decent Burbank, Ca. 4x shop spotted a bad fan clutch - that didn't fix the noise though.  Finally picked up a Sear's mechanic's stethascope - but everything sounded great through it.  The squeal noise  :sad: persisted.

Only area I couldn't get to with the stethascope was the water pump area (due to squeal noise being an engine-operating thing, which made getting to the water pump with the stethascope, challenging).  So, I upgraded the waterpump with a Flow-Kool - this didn't fix the squeal, but at least I got a better pump out of the unnecessary fix.  

Anyway, when all was said and done, it took a team of 3 mechanics almost an hour to track the noise.  Turns out it was due to a bad intake/exhaust manifold gasket.  Apparently there was damage in the gasket at the underside of the intake manifold, which made tracking the damaged gasket area, visually, challenging.  The mechanic that found it literally had to put weight on the intake - only then did the squeal noise change pitch - which tipped the guy off to the problem.   In 20 years of owning cars, that intake squeal problem really "took-the-cake" in terms of giving me an engine problem I, or a lone mechanic, couldn't figure out in short order.  

If you have a squeal, have checked out everything running off the accessory drive belt, no vacuum leaks anywhere, then get the intake/exhaust manifolds checked out and the gasket checked out too.  That did it for me.  Also take a look at TB area, especially if you've upgraded to a 4.0 or use a spacer - these areas are prone to cause noise too.  

Have to mention that the intake/exahaust gasket and leaks/noise there weren't talked about much in any jeep-related google searches I did.  Most of the suggestions there towards solving my squeal noise problem tended to run towards replacing the belt or accessories, the TB, the spacer etc.  

Also, should mention that if you have a high mileage 2.5 (well-maintained or no) you are probably going to see this kind of wear on the gaskets, maybe more so if you are twisting o pounding your rig alot off-road.  
Good luck :D

[chrisfranklin]

I reread this post and what you wrote:

To me, it sounds like it's coming from the driver's side of the engine, and towards the back / bottom.

That's the intake/exhaust side of the engine. The underside/rear of the intake manifold was where my gasket leak was coming from - driver's side back of engine like you are saying.

[Drummer Abe]

I have upgraded to the 4.0 TB / TB spacer / intake tube / and AEM filter, but I had the noise before then.  As of now, I'm planning on taking it to a mechanic early this week to see if he can diagnose the problem, and then I may tackle the repair myself.  The noise does appear to be coming out lower than the intake, but it may be on the bottom side of the intake, making it appear to be coming from the lower portion of the engine.  It's been a while since my last clutch / tranny repair, so it will be interesting if it's the throw out bearing.  One quick question - If it is the bearing, what kind of damage will it do if I drive it periodically on short trips before the repair?

[chrisfranklin]

Well alot of determining the source of the problem is the actual sound of the noise itself. Don't know the noise - unless you want to use a mike and create some kind of audio or audio/video file we can all catch from a link on this site - so we are kind of giving the best guesses we can as to what's causing it.  

(Personally, I think there is a future in remote auto-mechanic work for older cars, where an experienced, specialized mechanic directs the DIYer remotely and diagnoses engine problems remotely using an audio/video link of some kind, say the latest in digital cellular or standard broadband.  Course, newer ON-Star equipped cars already have a self-diagnosis mechanism that reports any problems to owners on a monthly basis)

For your Jeep, I'm thinking its the intake/exhaust gasket/manifolds or what the other guys are suggesting - bearing.

[Tall Boy]

Try a stethoscope to isolate the noise. My throughout bearing makes noise at idle until it goes into gear. It is a rattling noise.

[Drummer Abe]

Well, I took it to a mechanic today over lunch and had him look at and listen to it.  Well, we got nothing.  He doesn't think its the throw out bearing because the squeal doesn't change when I engage the clutch.  He also doesn't think it's the intake, because it's more of a bearing squeal than an air wheeze.  He did notice that my fan clutch is bad, and thinks that may be it, but of course, we couldn't duplicate the sound in the parking lot, only on the road.  However, I have been able to dupe the sound while sitting still and out of gear, so that eliminates the tranny and transfer case.  I'm taking it back in on Wednesday to put it on a lift and see if we can dupe the sound while someone's underneath.  We'll see how that goes... :?

[Jeffy]

I'd say idler pulley, or maybe the water pump.

[YJmechanic]

well a viscous fan clutch that is bad could make a squeling noise only when under a load and it sounds like a belt squeel.  upgrade to an electric fan and if it doesn't solve the problem it is still an upgrade and cheaper than a new viscous clutch.  my xj's went bad going down the road and i swear it was the belts and i stopped twice to check them and finally my arm moved the fan an a tiny squeek came out.  i took it off and spun it hard and it started squeeking so i popped an elctric fan in and never looked back.

[Drummer Abe]

Well, it wasn't the fan.  I replaced it Tuesday night.  I took it to the shop today, put it on a lift, and put it in gear with slight brake pressure.  No squeal.  But, of course, the ride back from the shop, I had to listen to it.  So, I went to my dad's for lunch, and he and I looked at it again.  I was able to duplicate the sound, parked and out of gear, so it's not driveline sensitive.  It's also not an air leak, or anything on the front of the engine.  We've checked and eliminated all of those possibilities.  He's thinking it's coming from the bell housing / starter area.  The mechanic mentioned the throw out bearing, but the squeal doesn't change when applying pressure to the clutch.  He also mentioned clutch springs.  My dad mentioned that the starter could be doing something goofy.  I'm still looking for ideas here, so have at it... :?:

[YJmechanic]

there are springs in the clutch disc meant to dampen the vibration but they shouldn't squeel.  the starter could squeel but only if it stayed engaged and then i would say it would squeel constantly.  i don't know what else to tell ya without being there.