So yesterday I did a coolant flush in my 98 2.5L and now when I go over 20 I have a loud howling noise and it’s very annoying and I replaced the belt and idler pulley and now I can’t think of what else it could be and I’m completely lost
Loud howling noise when driving after coolant flush
- Thread starter Joetwins
- Start date
Rubicon88
TJ Addict
Ok...
You loosen the center bolt on the idler and behind it is an adjustment bolt.
Is your belt tight? You say it is.
You should be able to twist the belt close to 90 degrees. Absolutely no more than that!!!!
I suspected that was going to come up as the 2.5 is a bit different.
Just below the PS pulley is an idler pulley, 15mm if I recall so just loosen that a bit and to the left of the PS pump just in front of the last bolt on the exhaust manifold on the PS pump bracket is the head of the adjuster. You can back off or tighten the belt at that point but be sure to loosen and re-tighten the idler bolt.
If the adjuster does not want to turn don't force it as it is a long threaded bolt and it will snap easily. Get behind the bracket with a small wire brush and lube to clean the threads out.
Look at the bolt head highlighted in pink.
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I loosened it and it seemed to make the howling a little worse and come sooner and so I tightened it a little bit and it made it com on a little later, but from what I’ve read that when it gets colder out that jeeps like to whine and howl and today is a little chilly out
Maybe, I also forgot to mention that when I was flushing the coolant that I had to pull the bet off the idler pulley and when I started it up the last time I didn’t put the belt back under so it all came off, do you think that might have something to do with it? Like I caught it nearly right away so it didn’t run long without a water pump
TJ2
TJ Expert
Normally I can figure it out pretty easy but I’m so lost on what it can be because I’ve tried nearly everything and still nothing
Check your belt routing closely, if you don't have A/C just go from the idler to the alt. Running without the water pump momentarily is not going to do any damage. My 2.5 has never whined or howled.
Could be simply a bad bearing in one of the idlers or the new one. . Best way to determine that is with a mechanics stethoscope, about $5 at Harbor freight.
TJ2
TJ Expert
I was wondering why you remove the belt to flush your coolant.
Your tensioner might be too stiff and need to be adjusted.
Your tensioner might be too stiff and need to be adjusted.
I didn’t completely take it off but on the thermostat housing there was a bolt on the bottom and I couldn’t get to it and I moved the belt from under the idler pulley to go to the bolt
Belt noise falls into three categories; squealing, chirping and growling.
A squealing noise, often heard at engine startup, sudden acceleration, air conditioning turn-on, or during a U-turn is typically caused by belt slippage due to improper tension and/or a badly glazed belt. Serpentine belt systems typically employ a spring loaded belt tensioning pulley and sometimes these can go soft.
Chirping is a result of belt vibration. This can occur due to improperly aligned pulleys, damp or wet conditions, and/or belt glazing. Minor pulley misalignment can result from excessive manufacturing tolerances or installation errors.
Growling is usually due to a faulty bearing in the tensioner pulley, an accessory component, or an idler pulley - if used.
Try this test: During a chirping episode use a spray bottle to mist the front and back side of the belt with water as its spinning (keep clear of all moving parts and don't stand in line with the belt). If the noise diminishes, then comes back - usually louder, the cause is surely belt related. If the noise remains the same, it may be caused by a faulty pulley or accessory component bearing. Removing the belt and turning each pulley by hand should indicate the faulty part, by noting rotational roughness or sounds.
Sometimes chirping can be reduced or eliminated - for a while, by removing and reversing the belt's direction. A new belt typically runs quiet, and is the best solution, as the rubber surfaces are more compliant. Roughing up the pulleys of a high mileage vehicle with a Scotch-Brite pad can help reduce future belt glazing and noise. Lubricants and belt dressing products may reduce noise temporarily but are likely to cause other problems - don't use them!
Renewing a serpentine belt typically requires unloading the tensioner with a wrench, and simply slipping the old belt off and new belt on. The tensioner and idler pulleys are also easy to renew, should replacement be needed.
A squealing noise, often heard at engine startup, sudden acceleration, air conditioning turn-on, or during a U-turn is typically caused by belt slippage due to improper tension and/or a badly glazed belt. Serpentine belt systems typically employ a spring loaded belt tensioning pulley and sometimes these can go soft.
Chirping is a result of belt vibration. This can occur due to improperly aligned pulleys, damp or wet conditions, and/or belt glazing. Minor pulley misalignment can result from excessive manufacturing tolerances or installation errors.
Growling is usually due to a faulty bearing in the tensioner pulley, an accessory component, or an idler pulley - if used.
Try this test: During a chirping episode use a spray bottle to mist the front and back side of the belt with water as its spinning (keep clear of all moving parts and don't stand in line with the belt). If the noise diminishes, then comes back - usually louder, the cause is surely belt related. If the noise remains the same, it may be caused by a faulty pulley or accessory component bearing. Removing the belt and turning each pulley by hand should indicate the faulty part, by noting rotational roughness or sounds.
Sometimes chirping can be reduced or eliminated - for a while, by removing and reversing the belt's direction. A new belt typically runs quiet, and is the best solution, as the rubber surfaces are more compliant. Roughing up the pulleys of a high mileage vehicle with a Scotch-Brite pad can help reduce future belt glazing and noise. Lubricants and belt dressing products may reduce noise temporarily but are likely to cause other problems - don't use them!
Renewing a serpentine belt typically requires unloading the tensioner with a wrench, and simply slipping the old belt off and new belt on. The tensioner and idler pulleys are also easy to renew, should replacement be needed.
I replaced the belt today and it only makes noises when I’m driving faster than 20
The 2.5 does not use a tensioner, strictly manual adjustment as I described above otherwise all good advice.
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