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New Noises from Engine Bay

duke183

NAXJA Forum User
Location
MD
It is a lovely day here in MD. There is no sun outside, only clouds, and it is raining buckets! Anyway, my 2000 XJ sport 4.0L has started to make some new noises.

When I start it up in general and give it a little gas it makes a noise, not sure what it is but sounds like it is a belt or something. Just a not so nice sound, but it always goes away after it warms up. Is that normal?

But the worst part is it now idles louder with some tickets/beltish noise? Also, when it rains out and I put the defroster on it can make a loud squeeling noise from the belt. I turn off the defroster and put it on heat only it goes away (typically). Although, one time I turned it off and turned it back on 10 seconds later and it was gone.

Of course the key thing here is that after the jeep gets warmed up for awhile, I can have the defroster on all day and there is no squeeling, just that louder ticking (not knocking).

Anyway, it is a jeep thing I am sure but I dont understand it...which is why I come here to ask about it. What should I look into? Is it a big deal?
 
The primary suspect for the noises you described is the serpentine belt. It may need to be either "tightened" or "replaced". Also, look for shiny streaks in the belt; this is called glazing and if your belt is glazed, it has to be replaced.

Don't even bother tightening it if it has over 50k on it; just replace it. Goodyear Gatorback is a great belt that works well on the 4.0

If you do replace it, know that the serp belt on the 4.0 needs to be wicked tight to keep quiet. Every belt I've replaced on my 4.0, I've had to retighten after a few hours of driving to keep the chirps/squeals away.
 
You said it makes a ticking.. you might want to check all the pulleys on the accessory drive for bad bearings. Especially check the idler pulley for play and roughness in the bearings and the harmonic balance for separation.

As for tightness get a Krikit II from Napa, about $20. KR2 bar code 0 29769 35216 8
 
You say when you turn on the defroster it gets worse.. When you turn on your defroster your a/c compressor will kick on to. I would check that as well.
 
So, maybe replace the belt first and then see how it sounds? Is it difficult to replace?

I'd say check the tension, buy the above mentioned gauge and chances are it just need's tightened a bit. Worst case, you need to replace the belt and you will have the tension gauge to get it correct with the new belt.
 
so I replaced the belt and made sure the tension was tight. Now what, I havent had it make the ac noise again, but there is still a squeeling noise coming from under the hood that wasnt there before last week. Really annoying. Otherwise the thing runs fine, just some crazy noises. Should I be worried or just turn the radio up (I need to replace my speakers too, so thats not even a great option!)?
 
so I replaced the belt and made sure the tension was tight. Now what, I havent had it make the ac noise again, but there is still a squeeling noise coming from under the hood that wasnt there before last week. Really annoying. Otherwise the thing runs fine, just some crazy noises. Should I be worried or just turn the radio up (I need to replace my speakers too, so thats not even a great option!)?

Did you use a tension gauge or guess at it? Twisting or pressing the gauge with your fingers is no substitute for the gauge.

/opinion
 
so I replaced the belt and made sure the tension was tight. Now what, I havent had it make the ac noise again, but there is still a squeeling noise coming from under the hood that wasnt there before last week. Really annoying. Otherwise the thing runs fine, just some crazy noises. Should I be worried or just turn the radio up (I need to replace my speakers too, so thats not even a great option!)?



what you can do is while its running- spray some WD 40 on each pulley one at a time...when the sqeak goes away, theres the pulley that's making the noise. Also consider that the belt may be too tight and its pressing a bearing in a pulley too hard.

The ticking noise could possibly be an exhaust tick...exhaust manifold maybe be begining to crack OR the donut gasket at the collector is shot, maybe even exhaust manifold gasket. Too many different pitches of ticks to really narrow it down without hearing it.
 
That sounds like a really poor plan and a recipe for a silently slipping belt
 
I'd avoid the WD-40 too. Spritzing it with water can help diagnose a noisy belt. I'm guessing its a bearing going south, likely the idler pulley. Best time to check that out would have been with the belt off though.
 
what you can do is while its running- spray some WD 40 on each pulley one at a time...when the sqeak goes away, theres the pulley that's making the noise. Also consider that the belt may be too tight and its pressing a bearing in a pulley too hard.

The ticking noise could possibly be an exhaust tick...exhaust manifold maybe be begining to crack OR the donut gasket at the collector is shot, maybe even exhaust manifold gasket. Too many different pitches of ticks to really narrow it down without hearing it.

BAD IDEA. Never spray a lubricant on a belt. Substitute brake cleaner, it evaporates almost instantly but will still quiet things up for a second if the belt's at fault.
 
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