Noisy Alternator Decoupler Pully (One Way Clutch) [Archive] - The Chrysler Minivan Fan Club Forums

: Noisy Alternator Decoupler Pully (One Way Clutch)



bluebgone
12-24-2007, 08:44 PM
I have noticed on my 2002 Caravan, a distinct shut down noise which seems to be coming from the Generator Decoupler Pulley one way clutch. It is a wind down noise as the Alternator keeps turning after the engine has stopped.
Recently I got a 2003 T & Country with the same 3.3L engine and it has the opposite problem in the clutch. When the engine is started, the clutch makes a noise like it is innitially reluctant to spin up. It's only for 2 or three seconds in duration.
The service manual says that the purpose of the clutch is to reduce wear on the alternator bearing and to reduce noise.
I had never seen this clutch arrangement before.
Question? Should I be concerned enough to be looking for a replacement alternator? Both cars seem to be charging just fine.
Has anyone else had to replace this clutch.
The 2003 also has a low volume engine whine which varies with the speed of the engine. I have not yet had time to try to pin the source down.

Hokiefyd
12-24-2007, 08:53 PM
I personally remember only one other issue like this posted to this forum in the last few years (the alternator pulley, that is).

For the low volume whine, I'm thinking power steering system/pump. Extremely common for them to make this type of noise on these vans. We here have begun to consider reservoir (on top of the ignition coils) preventative maintenance. There's a small screen at the bottom of the reservoir that must tend to get clogged -- replacing the reservoir and a good fluid flush typically quiets things down. The reservoir is cheap -- generally between $20-30 at your local dealership.

Noxzema
12-26-2007, 05:40 AM
My alt. whined after i shut down the van. too. I replaced it the alt. The alt came with the decoupler pully. The noise was very annoying. The alt. or the decoupler also made a sound like marbles in a can? After replacement all is well!

x99j
12-26-2007, 12:17 PM
hello all! i am not meaning to hyjack. i'm new around these parts (just purchased an 01). i got a question? is the decoupler (one way clutch) on the alt there for fuel savings purposes? and what controls the clutch (the pcm?)? also is this the same system the g.m. silverado uses to cut the alt in and out? thanks for your time!

Hokiefyd
12-26-2007, 12:30 PM
It's not an "active" device (controlled by anything). It's a "passive" mechanical decoupler, very similar to an overrunning clutch on a starter solenoid for example. This may not be same brand/supplier as the ones on our vans, but the theory is the same:

http://www.tendeco.com/website/decouplers/decouplers.html

x99j
12-26-2007, 06:03 PM
ok i get it now it is more of a belt system shock absorber, that makes the accessories and belt last longer as well as reducing noise and vibrations. i guess with the increased elec load on the gen 4&5 it is a big help! thanks!

DASander
12-26-2007, 11:26 PM
As stated above, this was designed to be quieter and smoother with less shock load on the system. I am not a fan. I have never had a problem with mine, however, we have had a lot of trouble with these things at work. I do not understand why they would change an already functional design with this set up. I have been told both that they must be left in place, and also that they can be replaced with a conventional pulley. Some of the replacement alternators have been installed with conventional pulleys and no problems. I wonder how many otherwise o.k. alternators have been replaced because of pulley problems. These are great alternators that should give many years of trouble free service. These pulleys are a weak link.

x99j
12-27-2007, 07:30 AM
i was thinking: maybe it was an attempt to cure the belt coming off syndrome that some had when they went through water and the noise problem? but to me it sounds like an iffy engineering venture. just another thing to go wrong on todays already comlicated vehicles? mine has one on it and if the alt goes bad (right now it is working as should) i will replace it with a non decoupler pulley. i'm sure i could find a pulley for a replacement one. i have always been a fan of denso alts. i have had some on other vehicles and they can go 200,000 +.

Al Steadman
01-02-2008, 08:07 AM
You can not replace the alternator decoupler with a solid conventional style pulley or simple one way clutch. This device (alternator decoupler) is essential for this vehicles belt drive. If you decide you want to replace it with a solid pulley, I would think twice. If you go ahead and do this, you will begin to wonder why your tensioner and belt keep wearing out, or even why your belt begins to fall off or even breaks. Believe me when I say, that if this vehicle did not need an alternator decoupler, then Chrysler would not have installed it. Go to www.tendeco.com and read up on this device if you need more info. Under the tech tips section there is also some videos that show exactly what can happen if you decide to swap this device out for a solid pulley.

Once again, I caution you to think twice. These alternator decouplers are available in the aftermarket for a very resonable price ($30-$40) so in many or most cases you would not have to buy the whole alternator! Fixing it right is actually easy and cost effective. You can buy the alternator decoupler at your dealership $$$ or places like www.iat-usa.com. There are many companies that sell alternator parts to alternator rebuilders, that stock the aftermarket version of this product. Companies like International automotive trading, RCP Canada, as well as Dubois Marketing. Look for the name RotoRx IDP. The name RotoRx is aftermarket name given to the decoupler. The IDP stands for Isolating decoupler pulley. It is exactly the same as the original in fit and function. Once again go to www.tendeco.com and see the videos and read the presentations that are in the tech tips section. You will be amazed and may actually learn something.

AL

shipo
01-02-2008, 08:17 AM
I'm not saying that you're wrong, however, if everything you say is true, then why do the belts on our 1998 (no decoupler on that van) last an easy 60,000 miles (that's as far as I'll run them, I don't actually know how far they'd run)?

Further more, while I don't know this for a fact, our 2003 doesn't seem to have a decoupler (although I haven't looked too closely), and it's factory belt lasted something like 88,000 miles.

Al Steadman
01-02-2008, 08:59 AM
I'm not saying that you're wrong, however, if everything you say is true, then why do the belts on our 1998 (no decoupler on that van) last an easy 60,000 miles (that's as far as I'll run them, I don't actually know how far they'd run)?

Further more, while I don't know this for a fact, our 2003 doesn't seem to have a decoupler (although I haven't looked too closely), and it's factory belt lasted something like 88,000 miles.


The reason why your 1998 belts have lasted is because they belt drive is completly different. The tension levels as well as geometry as well as a different alterntaor (less output). Your 1998 van is acutally known for belts falling off while driving through puddles or snow drifts. There is actually a special fix kit available for repairing this very problem. Google 38379K and you will read hundreds of posts about that topic.

Your 03 van has a 160 Amp alterntor and this changes things dramaticly. Your 03 definetly has an alternator decoupler, however it has lasted longer than some 01s because it is a newer level of decoupler. 2001 was the first year for alternator decouplers on these vehicles. Hope this answer helps.

AL

shipo
01-02-2008, 09:18 AM
The reason why your 1998 belts have lasted is because they belt drive is completly different. The tension levels as well as geometry as well as a different alterntaor (less output). Your 1998 van is acutally known for belts falling off while driving through puddles or snow drifts. There is actually a special fix kit available for repairing this very problem. Google 38379K and you will read hundreds of posts about that topic.
We've discussed the belt throwing issue any number of times here over the last year or two. From my perspective, these vans DO NOT have a problem with the "belts falling off while driving through puddles or snow drifts." Ours has been through a huge number of both over the last 150,000+ miles and never once thrown a belt. What that means to me is that belt throwing on some vans is a symptom of some other issue or fault and not the actual problem, and that buying the Gates kit is just covering up the underlying cause.

FWIW, while our 1998 doesn't have a 160 amp alternator, it does have a 120 amp unit that is no slouch when it comes to leaning on the belt.


Your 03 van has a 160 Amp alterntor and this changes things dramaticly. Your 03 definetly has an alternator decoupler, however it has lasted longer than some 01s because it is a newer level of decoupler. 2001 was the first year for alternator decouplers on these vehicles.
I just went out and checked and had somehow overlooked the pully arrangement until now. Yes, it does have a decoupler, problem free after 104,000 miles.

Hokiefyd
01-02-2008, 09:39 AM
I've never heard of a decoupler until these vans. None of my Cadillacs have had them, and they've both had 140-amp alternators. I wonder what specifically is different about the accessory drive that "requires" the use of such a device on these vans -- and I wonder if I could perceive a difference in NVH on the Cadillac if I installed a decoupling pulley on it.

DASander
01-02-2008, 11:46 AM
I still think these decouplers were a solution to a problem that never existed, thus creating a new problem. If it ain't broke... DON'T FIX IT! Why would engineers add mechanical complexity to something so simple and trouble free as an alternator pulley? I just don't get it. Yet one more thing to go wrong. The argument that the benefit of these things out weighs the problems is a tough sell to me.

nkuenkel
02-05-2008, 09:27 PM
I am very interested in your post, Shipo. I am having the exact same problem with my 2003 DGC with 85,000 and a new alternator (maybe 4k on it). I don't think it has a decoupler unless it came with the alternator I bought and I didn't notice it. I will have to do some checking.

Jeepman
02-05-2008, 10:00 PM
On my 2002 GC the alternator has a clutch type assembly on the end of it which you reuse when replacing the alternator. It isn't all that noticeable, but it is there. The Mechanic showed me it. For a new one I believe one has to go to the Dealer.

shipo
02-05-2008, 10:55 PM
I am very interested in your post, Shipo. I am having the exact same problem with my 2003 DGC with 85,000 and a new alternator (maybe 4k on it). I don't think it has a decoupler unless it came with the alternator I bought and I didn't notice it. I will have to do some checking.

Okay, ya got me. Which "exact same problem" are you referring to on your 2003? ;)

nkuenkel
02-05-2008, 11:01 PM
I am having the same trouble with my 2003 DGC EL so I am very interested in this thread. I went and took a look in my Haynes manual and there is no mention of a decoupler pulley for the 2003-2006 models.

nkuenkel
02-05-2008, 11:04 PM
The problem I was referring to is a whir or sound like something continues to spin for a second or two after the engine is shut down. Comes from the general area of the alternator but that tests out just fine.

bulldog van
02-06-2008, 12:08 AM
The problem I was referring to is a whir or sound like something continues to spin for a second or two after the engine is shut down. Comes from the general area of the alternator but that tests out just fine.

Sounds normal to me. My ex 2001 caravan 3.3L did that whenever engine is shut down, i.e. like a whistle sound from a turbine. Probably comes from the remaining vacuum in the intake manifold sucking air through the IAC valve of the throttle body.

daklein
02-09-2008, 11:06 AM
Hi van guys, I didn't realize the chrysler vans had decouplers on the alternators.

Could anyone tell me which years and models or engines had them?

you mention 2001 had it, and then a different design one in 2003? (through present model years?) there are at least a couple of designs for these: one is simply a one way clutch, and another adds a torsional spring that absorbs some of the torque pulse from each cylinder firing. so which design do your vans have?

I'm hoping to use these for something else,:scifi: I think I want the simple one way clutch type, not the torsional spring type. Maybe I can find at junkyards if I know which year I want.

BTW, another reason, or possibly even the primary reason, to add this mechanically more complex and less reliable pulley: fuel economy. having a decoupler for the alternator lets the accessory drive be designed with lower belt tension, while still meeting nvh, belt and tensioner resonance constraints. the lower belt tension reduces side load on the alternator, ps, a/c and reduces the losses in the belt and bearings, making it take slightly less torque from engine to drive all the accys. So when you drive to Florida with the kids, you'll save $1 on gas.:thumb: That way, all you minivan drivers will offset the CO2 that Al Gore emits:eek: as he flies all around the world.:rolleyes:

Thanks!! Dale

Jeepman
02-09-2008, 01:17 PM
The low whirring noise on my 2002 GC Sport 3.3 with the 160 amp alternator was the alternator. Once the Mechanic saw the clutch pulley he said he was worried that maybe the noise he heard in his Mechanics' stethoscope was coming from the clutch. He replaced the alternaror, reused the old clutch pully, and the noise disappeared. Most alternators seem to come without the clutch pulley, including those from the Dealer here, but the price variation leads me to believe that some come with the pully at almost $100.00 more. There was a thread on this clutch pulley in the past few days. One person there got the complete assembly and didn't know he had a clutch pulley - the clutch is within the pulley.
This pulley is not unique to Chrysler products.
There were some Dodge clutch pulleys on e-bay earlier this week at about $50.00, I believe. I will look up the referenced thread and add it.
I would't use something other than the appropriate clutch pulley.
As to how long they have been in assistance, the e-bay add was covering 2001 to 2005. Wasn't the alternator on the back in previous models, it's on the front in mine.

Jeepman
02-09-2008, 01:46 PM
A previous thread on this was:
2003 Grand Caravan Whir after shutting ignition off

The e-bay site, showing a picture of the clutch pulley was:
http://cgi.ebay.com/ebaymotors/Clutch-Pulley-for-Chrysler-Alternators-2001-2005_W0QQitemZ230218804947QQcmdZViewItem?hash=item 230218804947
Bidding has ended.

Ben100
08-03-2010, 04:53 PM
You can see a picture of the clutch pulley on this site.
They have the original Litens OAD decoupler pulley:
http://www.americanenginesco.com/servlet/the-15/Liten-Alternator-Pulley-Dodge/Detail
Very helpful, answered all questions.