Alternator pulley/decoupler? Help please

Lancer · **Posted:** Sat Feb 11, 2012 12:19 pm

Ok - cold morning here (-8C) went out and started up the jeep to warm up a bit while I scraped the ice off all the windows. I hear a sort of chirping sound from under the bonnet at the front. I'm guessing that the alternator pulley is on its way out. Am I right? If so, do I have to change the serpentine belt at the same time as the pulley? If so - anything else?

If I have to change it, then I'll take the opportunity to fit the Hayden clutch and nylon fan at the same time - both currently sitting in my shed.

Thanks for any help.

papaindigo · **Posted:** Sat Feb 11, 2012 12:42 pm

It's certainly possible. Pop the hood; take off the plastic engine cover; crank the motor up; at idle look down the serp belt to the serp belt tensioner - if it's bouncing up and down and you have lots of red dust on the alternator pulley face then the clutch in the pulley is shot. IMHO it's best not to drive much if at all until fixed lest you also destroy the serp belt, relatively cheap, and the serp belt tensioner, $200+. Assuming it's just the alternator clutch a replacement runs ca. $80 from like http://www.americanenginesco.com/servle ... CRD/Detail and DIY replacement is apparently not too difficult.

If the problem just started the serp belt is probably ok but if that belt has ca. 50k miles on it I'd replace it as a matter of routine. A Gates K061130 belt is currently $38.95 w. shipping on Amazon.

Lancer · **Posted:** Sat Feb 11, 2012 12:52 pm

Thanks - the jeep has done 43k miles, and so far as I am aware, the belt has never been replaced during a service.

Amazon US won't ship car parts to the UK - Rockauto does however

So - belt, alternator pulley(assuming the red dust is there), and serp belt tensioner is it then?

Lancer · **Posted:** Sat Feb 11, 2012 1:03 pm

Just thought I'd say - the belt alone with USPS priority mail is £58 - that's about $85!

papaindigo · **Posted:** Sat Feb 11, 2012 1:53 pm

Should have looked at your signature; hopefully you can find a supplier on your side of the pond or at least one that will ship to you for the alternator pulley. You shouldn't need to replace the serp belt tensioner if this just happened I doubt that it has any problems. Assuming the alternator pulley/clutch needs replacement, per my earlier comments, then I'd lean toward a new serp belt or you can just purchase a new one to have on hand and see if that old one will go another 7K miles which it should if there is no obvious belt damage.

I have a spare new Gates K061130 serp belt that I'd love to get rid of. If you are interested drop me a PM or email and we can discuss as I think it can be done for well less than $85. I think it will fit in a smallish USPS flat rate box but I don't have a clue about customs at your end. Wish our trip your way in March had not fallen thru or I'd just bring the xxx thing.

Lancer · **Posted:** Mon Feb 13, 2012 6:53 pm

Ok - well started it up - belt wasn't bouncing around and I couldn't see any red dust. Chirping coming from right side of engine (as you are facing the vehicle). I didn't examine more at that point as it was snowing, strong wind and -9C and I was freezing!

I drove it for about 60 miles and then listened and had a look under the bonnet, and the sound had gone. I think getting another belt is a good idea - even if it's ok now, it'll need replacing soonish and maybe a spare alt pulley would be a good idea "in case".

Any thoughts?

papaindigo · **Posted:** Tue Feb 14, 2012 7:53 am

If the sound comes back pull the viscous heater relay, which will stop the viscous from engaging, if the sound goes away the viscous heater bearing may be going. The bearing is replacable but the clutch is not see viewtopic.php?f=5&t=60567 . Whenever you so replace the serp it's a good idea to check out the bearings on the various spinning things the belt route over (2 idlers, tensioner, PS pump, AC compressor, and alternator).

Spare alternator pulley, up to you. I don't know that it's worth the bother but then I do have a spare alternator but only because I stumbled on one when I had some spare cash.

jws84_02 · **Posted:** Tue Feb 14, 2012 1:03 pm

Forgive me if this has already been answered but what relay is the viscous heater

papaindigo · **Posted:** Tue Feb 14, 2012 1:23 pm

See the power distribution center section of your owners manual or download a copy from Sam's NOOB guide. It's R36 but you have to pay kind of close attention to the PDC label on the lid to figure out which on that is. FYI the lid sometimes requries a bit of wiggling to close, the relay may be in there really tight (I had to grab mine lightly with pliers and wiggle it to remove), and it may be a good idea to drop a little piece of ethafoam into the recess to keep the contacts clean.

Alternator pulley/decoupler? Help please

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