Annoying chirp???

jws84_02 · **Posted:** Sat Feb 11, 2012 10:22 pm

Hey guys,

I recently started having a chirp. I'm pretty sure it's coming from inside the timing cover. The sound is constant at all rpm's. I have noticed no difference in driving or performance, etc. I'm guessing it's one of the pulleys in there???

My crd has 90k and I was planning the entire timing belt job soon but not this soon

msilbernagel · **Posted:** Sat Feb 11, 2012 10:40 pm

jws84_02 wrote:

Hey guys,

I recently started having a chirp. I'm pretty sure it's coming from inside the timing cover. The sound is constant at all rpm's. I have noticed no difference in driving or performance, etc. I'm guessing it's one of the pulleys in there???

My crd has 90k and I was planning the entire timing belt job soon but not this soon

If it's inside the timing cover I wouldn't wait long... isn't the usual source of this chirp due to the alternator clutch failing?

Mark

jws84_02 · **Posted:** Sat Feb 11, 2012 10:46 pm

msilbernagel wrote:

jws84_02 wrote:

Hey guys,

I recently started having a chirp. I'm pretty sure it's coming from inside the timing cover. The sound is constant at all rpm's. I have noticed no difference in driving or performance, etc. I'm guessing it's one of the pulleys in there???

My crd has 90k and I was planning the entire timing belt job soon but not this soon

If it's inside the timing cover I wouldn't wait long... isn't the usual source of this chirp due to the alternator clutch failing?

Mark

It might be the alt decoupler. I'm not 100% sure it's coming from the timing cover area. It was dark out when I looked in there. What are other symptoms of the decoupler failing?

jws84_02 · **Posted:** Sat Feb 11, 2012 10:54 pm

jws84_02 wrote:

msilbernagel wrote:

jws84_02 wrote:

Hey guys,

I recently started having a chirp. I'm pretty sure it's coming from inside the timing cover. The sound is constant at all rpm's. I have noticed no difference in driving or performance, etc. I'm guessing it's one of the pulleys in there???

My crd has 90k and I was planning the entire timing belt job soon but not this soon

If it's inside the timing cover I wouldn't wait long... isn't the usual source of this chirp due to the alternator clutch failing?

Mark

It might be the alt decoupler. I'm not 100% sure it's coming from the timing cover area. It was dark out when I looked in there. What are other symptoms of the decoupler failing?

Nvm... I found symptoms of it a couple threads down

papaindigo · **Posted:** Sun Feb 12, 2012 8:46 am

Alternator decoupler diagnosis - pop plastic engine cover; look at front of decoupler (is it REALLY covered with nasty reddish dust - not just a light dusting); crank up the engine and at idle look down the serp belt to the serp belt tensioner (is it bouncing up and down). If either/both are yes it's probably the decoupler. Repair options 1) new/rebuilt alternator with new decoupler (OEM or if they can get one Autozone Duralast 15457 or http://www.maniacelectricmotors.com/jeep.html seems to have done well and quickly by some members) or 2) new decoupler - check around on-line they cost about $80 and can be done DIY.

spitfire36o · **Posted:** Thu Feb 16, 2012 3:40 pm

Did you find out if it was the alternator pulley or timing belt?

jws84_02 · **Posted:** Fri Feb 17, 2012 9:07 am

spitfire36o wrote:

Did you find out if it was the alternator pulley or timing belt?

Well I unplugged the viscous heater relay and the noise hasn't come back. I didn't have the symptoms of the decoupler so this was my next guess.

papaindigo · **Posted:** Fri Feb 17, 2012 11:20 am

Take a look at viewtopic.php?f=5&t=60567

You might want to check and see if the bearing on the viscous is running hot (feel it after a bit of a drive) as it's apparently possible for the bearing to go and eventually take the viscous clutch with it. Bearing is replacable but evidently the clutch is not.

jws84_02 · **Posted:** Mon Feb 20, 2012 12:44 pm

The darn noise is back. It seems to do it when it warms up(motor). So I shut it off and moved the fan blade. It is the same sound but obviously not as fast.

Do you guys go with the Hayden fan clutch and is it as simple as taking the 4 bolts off? And then what??

papaindigo · **Posted:** Mon Feb 20, 2012 2:04 pm

Yes the Hayden clutch is highly recommended - much more durable, cheaper, and kicks in earlier in the temperature rise cycle.

According to the FSM writeup you have to pull the fan and fan shroud, just like you do when changing the timing belt, but once that's done the clutch/fan are held together by 4 bolts. Cautions/comments:
1. the tubes/hoses on top of the fan shroud and held onto little plastic block, which are pressed into the shroud, by what amounts to plastic wire ties. Don't try to remove the blocks from the shroud; IMHO it's better to clip the wire ties and replace them upon reinstall.
2. some folks have damaged their radiator core when removing the fan and fan shroud together. I'd strongly recommend placing a towel or piece of cardboard in front of the fan during removal to prevent that from happening.
3. the fan shroud is secured to the radiator by 2 short bolts about 1/2 way down on both sides and retaining hooks on the bottom. Be careful on those bolts as 1) the nuts they go into are not fixed in place rather they simple slid into a recess so take care not to drop them during disassembly and 2) the length of the bolts is critical so take care to reuse the bolts you removed (one member found a dealer TB job was done without paying attention and they put things back together with long bolts that punctured the radiator)

Annoying chirp???

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