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Important alternator Info - YOU NEED TO KNOW

39K views 33 replies 15 participants last post by  andyg 
#1 ·
Greetings to all,


I feel the need to clear things up for everyone who owns a 4th generation minivan. If you have the 3.3L or the 3.8L V6 then please read on. On your alternator there is something called an alternator decoupler. It is a clutch and spring mechanism inside the alternator pulley. This device is used to absorb vibration within the belt drive system. When the alternator decoupler fails, you may hear a buzz noise on shut down, or the alternator will fail to charge(due to the clutch being broken inside) or your belt tensioner may exibit excessive movement.

What you need to know.... is that many big box stores are selling alternators with an inferior "simple clutch pulley" or a solid pulley on the alternator. There are two distintly different kinds of these "Clutch pulleys". One has the internal spring (Litens) and all the others do not. Make sure that if you ever decide to change the entire alternator for whatever reason, MAKE SURE IT HAS THE RIGHT PULLEY ON IT. The right one being a Litens Isolating Decoupler pulley and not just a "simple one way clutch". Simple one way clutches have only 50% of the function of the Litens IDP. These two pulleys are not internchangeable. Your belt drive has been designed with a Litens IDP for a reason. Don't buy an alternator with an inferior (lower cost) pulley.
I have read in these forums (an others) where people have changed their alternator pulley from a Litens IDP (OE) to a simple one way clutch. They did this either to save a bit of money or lack of knowledge about what pulley the vehicle required. Once this happens, people can't seem to understand why the vehicle's belt sometimes falls off, or why the belt tensioner keeps wearing out, or why the bearings in the waterpump keep failing. It is because the belt drive was designed with the Litens IDP and not the lower cost and lower function of the simple one way clutch. The Litens IDP is not hard to change and is currently available in the aftermarket. You can purchase the aftermarket version from www.iat-usa.com or if you want to pay more for the same part (OE) you can buy it seperately from the $tealership. Both the aftermarket version and the dealership version are made by Litens and are of the exact same OE quality.

Bottom line is ... know what you are buying and don't settle for the wrong parts just because they are a couple of bucks cheaper. Spending a couple more bucks now to put the right part on your vehicle will save you money and headaches down the road. Installing the correct pulley on your alternator will make you belt, tensioner, idler pulleys, waterpump and alternator bearings last a lot longer. But don't take my word for it, research it for yourself! :thumb:

More information about Decoupler pulleys can be found at www.tendeco.com or www.litens.com.

Hope this helps everyone become an informed customer,

AL

Maybe this should be a sticky?:ThumbsUp:
 
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#2 · (Edited)
That was great information. Thanks. Yes, the clutch pulley started with the Generation 4, has been used by lots of European manufacturers for years, Mitsubishi since 1999(I think) and supposedly saves wear and tear on the serpentine belt and items driven by the belt.

Prices can be all over the place for alternators depending on warranty, clutch pulley or not AND per your Post a "quality" clutch pulley or not.
When I had my alternator replaced over a year ago (October 2007), the prices for the alternator were:
Sangsters Automotive Supplies (local): $260; two year warranty; no clutch pulley.
Dealership (trade price): $220; one year warranty; no clutch pulley.
Carquest: $320; one year warranty; clutch pulley included.

Sangster's was just up the road from the repair shop (much more convenient) so I used that one and had them use my old clutch pulley.
Funny thing, the Mechanic said "I'm a bit worried, I want to show you what I have done (took me to the vehicle), your alternator has a clutch pulley and it may have been the source of the noise, I'm worried I didn't fix the problem although it sounds like it's fixed. If not, the part will likely have to be purchased from the Dealership. Keep an eye on it and let me know."
The job was a success and all is well to this point in time.

I have been trying to find out, in numerous Posts on here, as to what tool is used to remove / install the clutch pulley. From research on the web, there appears to be a special tool required. Can you enlighten me on that? It would be much appreciated and close out a "cold case" file. :thumb:
 
#5 ·
The special tool to remove and replace the alternator decoupler can be viewed and purchased from this link.

Hope this helps.

http://www.millerspecialtools.spx.com/Detail.aspx?id=498

Having this tool is the only true way to torque the decoupler to the proper torque spec. Most dealerships have this tool or something very close.
Thanks so much. I can now put the "cold case" box back up on its shelf. :thumb:
That's a pretty expensive ($59.04 US) and single purpose tool. It looks like I have one of those clutch pulleys on my Jeep as well (they mention TJ in their listing). Oh my! Labour for the Van was only $58.00 ..............
 
#4 ·
Is there any point or benefit to using a decoupler pulley in an application that didn't originally use it? My '97 Dakota for example. It appears that they NOW use it (AN series), per your link to the tool above, but mine doesn't have one. Maybe it did originally?? Doubt it -- it is a Denso alternator...original I think.
 
#6 ·
Jason,

The short answer is no. Belt drives are designed as a system. Your 97 Dakota was not originally designed with an alternator decoupler and therefore do not need one. Also they are application specific and therefore there is not one that is available for your Dakota so you could not put one on even if you wanted to. Most belt drive systems that have an alternator decoupler have a super low tension tensioner. Adding the alternator decoupler allows engineers to use lower tension on the belt. This lower tension, allows the all of the bearings (waterpump, alt, a/c comp, etc) to last longer while still having just enough tension to not allow belt slip at each pulley. The decoupler also helps eliminate belt chirp caused by the heavy inertia of the alternator rotor.

AL
 
#7 ·
Too bad the waterpumps and pullies on these vans still wear out way too early.

Someone failed when the designed that system.
 
#8 ·
Replaced an alternator on mine so far. That's it, other than the serpentine belt.
 
#11 ·
If it is a timing belt driven pump on the Honda, then it is common practice to replace it with the belt.
The 3.0 Mitsu-sourced Chrysler V-6 is that way (I didn't replace the pump at 60,000 mi with no issues) and so are the later 4 cylinders. (I think the 3.5 and 4.0 may be that way too)
If the interval for the belt is at 100,000 mi, it is definitely a good idea to replace the pump too. That is an expensive service......Why do it twice?
I hate defending Hondas.:eekkkk:
 
#12 ·
My guess is that it is a timing belt driven pump.
Very deceptive they were. Said that sometimes they don't replace the pump if it looks okay and they would get his permission to replace it if it needed it. Because of that statement he went with that Dealership instead of another that said they would recommend replacing the pump regardless. Of course they replaced the pump and didn't get his consent ... they did give him a bill for the work though. I said go back after them, which he is prone to do and he did and obtained some kind of a credit on future business which he has already used.
The Honda CRV has a resistance engine I believe, so it would likely self destruct if a belt or water pump went. Ain't that sweet:ask_wsign :jpshakehe
 
#13 ·
The reason why they replace the water pump when they change the belt ( it is a timing belt) because you have to take off the belt to replace the pump. Well if your down there replacing the belt, you might as well replace the pump. I think you are surpose to replace belt somewhere around 106,000 miles. The water pump on my friends caravan went at 80,000 miles.:angrya:
 
#14 ·
#17 ·
Greetings to all,
Bottom line is ... know what you are buying and don't settle for the wrong parts just because they are a couple of bucks cheaper.
How can I tell if the alternator I want to buy has the right decoupler pulley?
 
#18 ·
The best way to tell is by part number on the pulley, but to do that you need to remove the plastic cap.
Another way to tell is the part will be black in color, and have a plastic cap that snaps into the pulley instead of over the pulley.
You can always ask to see if the remanufacturer of the alternartor uses Original Equipment parts when they rebuild the alterntaor. Ask if it has the "Litens" Isolating decoupler pulley and don't buy it if it doesn't.

For these Minivans (and many other vehcicles) the Litens decoupler pulley is the proper part (the one that was chosen when the system was designed) and should be insisted upon when replacing either the decoupler or the entire alternator.

Don't take it from me, do your own research.

AL

p.s. many one way clutch manufacturers are trying to make their aftermarket replacment pulleys look exactly like the Litens decoupler. They are doing this to confuse the purchaser into thinking they are getting the Litens decoupler when they are really only getting a one way clutch pulley.

One true way to make sure you are getting the right part for your vehicle is to go to www.iat-usa.com and buy the Litens decoupler from them. They are an approved distributor of the Litens decoupler.
 
#22 ·
Atoman,

No, it is not possible to replace just the bearing. These are sealed units and the bearing is locked into place. Visit www.iat-usa.com and order a new one. They are not that expensive at all. They are available at the dealership or in the aftermarket. If you buy one in the aftermarket, make sure it is a Litens one. There are many people out there trying to sell inferior one way clutches as a direct replacement for the Litens OAD. Buyer beware. Also check out www.decouplerpulley.com a new website with tons of info on the Litens OAD!

AL
 
#23 ·
Makes sense to me, if the water pump is driven by the timing belt, to replace the water pump when the timing belt is replaced. Had that done twice, once on an 00 Lexus RX, and once on an 02 Lexus RX. Bearings wear out. It costs $500 to replace a timing belt, and I can include replacement the water pump for little more than the cost of the part (say $50), that's $550 at 100K miles. If I don't replace the water pump, will the bearings in that pump last another 100K miles? If it goes at 150K, I'll have to pay $400 to replace the water pump, because most of the labor is the same labor involved in replacing the timing belt.

Oh and by the way, while you're in there replacing the water pump, you might as well replace that timing belt...
 
#24 ·
any1 know what the difference is between 920834 and older 920685 (4861506AG vs AE)? (in terms of life expectancy?)

Thanks AL, they're not cheap (if they last only 50Kmi and mopar wants between $50-$100 for each + special tool..)

Does IAT sell to DIY'ers or only to rebuilders?
 
#25 ·
Well, it looks like it's time for a pulley on our 2003 (getting noisy) and here's what I've found after a bit of digging:
  • The IAT Inc. site http://www.iat-usa.com doesn't apparently sell parts via the internet (and may not sell to individuals)
  • Napa-Online http://www.napaonline.com sells the Litens/Gates part # 37105P for $85.49
  • The Litens site http://www.decouplerpulley.com doesn't appear to sell parts via the internet
  • The http://www.dodgeparts.com site lists the following pulleys for the 3.3 and 3.8 liter alternators:
    [*]4861506AC -- 2001-2002 -- MSRP: $41.70 -- Retail: $30.00
    [*]4861506AD -- 2003-2004 -- MSRP: $41.70 -- Retail: $30.00
    [*]4861506AE -- 2005-2005 -- MSRP: $41.70 -- Retail: $30.00
    [*]4861506AG -- 2006-2007 -- MSRP: $98.95 -- Retail: $71.16​
I'm thinking that I'll be ordering the new pulley from the Dodge Parts site. :)
 
#26 ·
Thanks for the detailed info. :thumb:
Now we know why the 2006 Caravan won the J.D. Power award for reliability - a more expensive (hence more dependable, I would assume :biggrin:) decoupler for the alternator.

Still with the original decoupler on my Van. The alternator was replaced though, a couple years back.
 
#31 ·
This Overrunning Alternator Decoupler, is it spring loaded to absorb irregularities in the drive system, without the use of a one way clutch? So that when I hold the alternator in my hands the pulley feels like a solid pulley? I just want to make sure it has the right alternator. It is the factory alternator. The spare alternator I have is also factory, donated from a junked Caravan. The pulleys on both feel like solid pulleys. Perhaps the spring is too strong for the hand to compress it against the stationary inertia of the alternator guts? They certainly don't have any one way clutch action.
 
#32 ·
I believe that started with the 2001s.
 
#33 ·
Ahh OK reading around it seemed like the 3rd gens.
 
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