How to Replace Alternator Decoupler Pulleys - Wrenchin' Up

Many vehicles today are equipped with an Alternator Decoupler Pulley to keep the serpentine belt running smoothly. They are a relatively maintenance free item but do, occasionally, need replacement especially when the alternator is replaced. When defective the serpentine belt behavior starts to look like the video insert with no decoupler in the system. There will also be a "buzzing" noise" after engine shutdown if the bearings are shot. You would feel grinding by turning it by hand and the pulley could also spin freely in both directions. Rapid belt wear would result. My guest, Rob Laing from Litens, shows us why we need them, how they work and how to replace them.
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Wrenchin' Up with Jim Bates strives to deliver automotive technical information and ideas from manufacturers and engineers to interested technicians and enthusiasts on a weekly basis. A new video is uploaded almost every Wednesday.
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Twitter: @jimfbates

[@gartheligon140]

Manufacturers found a way to sell alternator pulleys and tools. Never had cause to replace a solid pulley, my system doesn't have a spring loaded belt tensioner. The more manufacturers improve on technology the worst it gets, and it's more costly to.

[@WrenchinUpwithJimBates]

Hi - Thanks for watching and sharing your opinion!

[@antho7475]

I am a 32yr master ase. mechanic . I agree, Somethings are better on paper than in practice. I would rather replace a tensioner every 100,000 miles than the alternator pulley. When it locks up the belt fails and causes even more damage. They can keep it

[@wcjcnc]

I’ve never even heard of a decoupler pulley until today. My alternator is making a racket so I thought the bearings were going out so I bought a rebuild kit. I took the alternator off today but notice it was very smooth when I spun it by hand. Looking around online I found a video about the noise a bad decoupler pulley makes when it’s going bad. I noticed the pulley isn’t true when I spin it. Glad I figured it out before talking my alternator apart. The bad part is, nobody locally stocks the pulley so I had to put it back on so I can go to work tomorrow and fix it next weekend

[@WrenchinUpwithJimBates]

Hi - Thanks for watching and sharing your experience!

[@seth_ap148]

Chased a noise in my 2015 Kia Sportage for years.. turned out to be the decoupler, never have I been so happy to fix an annoying rattle.

[@WrenchinUpwithJimBates]

Hi - Thanks for watching and sharing your experience!

[@spelunkerd]

These are designed so that the clockwise movement of the belt automatically tightens the pulley with its right hand threads onto the shaft, which explains why these pulleys are so difficult to take off. They get retorqued, every single day of their lives. So, I'll hazard a guess that even suboptimal mounting torque will rarely cause a problem. As far as impact wrenches go, yes ideally these should not be fastened with an impact. On the other hand, I bet robots mount them in the factory with an impact, and pro shops routinely use impact wrenches despite the risk. To remove the pulley from an alternator without an impact, bring two four foot cheater bars to extend your two wrenches, and if possible leave the alternator mounted in the car to hold it steady. It will never come off otherwise. Remember the center wrench that holds the shaft applies clockwise torque, the outer pulley wrench spins counterclockwise to remove.

[@WrenchinUpwithJimBates]

Hi - Thanks for watching and your valuable experience! This should help resolve the many questions on this subject.

[@mjdizzle94]

Thanks for the video! Helped out a lot. New pulley is order and Installing it this week along with new Serp belt and tensioner. My 16’ Sierra makes a buzz sound, a sign that pulley is bad

[@WrenchinUpwithJimBates]

Hi - You're welcome and thanks for watching and sharing your experience!

[@valuedcustomer9614]

You can only reinstall and re-torque an OAD pulley correctly with a special tool that also holds the center shaft. It cannot be done properly using just an air impact wrench (as in this video). For example, Litens brand OAD pulleys were used on 2001 through 2007 Dodge and Chrysler gen-IV minivans. Chrysler and Litens recommend using a Miller Tools part # 8433 or 8433A for these pulleys as mounted on Denso alternators. Note that other different pulleys will require different special tools. There are cheaper knock-off tools and kits made by companies like Lisle and OEM Tools, but they're not as strong as the Miller tools.

[@WrenchinUpwithJimBates]

Hi - Thanks for watching and adding your valuable input!

[@waynefoutz]

Chrysler added these to their minivans in 2001, because the first two years of the generation 4 minivans had an issue with throwing the belt when driving through a puddle. This solved it. The 2008 and newer models no longer have the clutch pulley.

[@WrenchinUpwithJimBates]

+wayne foutz Thanks for the input and thanks for watching!

[@robdonna1000]

just weld the 2 halves of the old pulley together. No need to remove it first. Worked for me.

[@WrenchinUpwithJimBates]

Hi - Thanks for watching and sharing your experience!

[@mostlymoparih5682]

kzbin.info/www/bejne/l5fNhJdujquFaaM This video is called Litens OAD™ Installation It shows the different alternators and procedures for the OAD pulleys and the torque settings. The procedure used in this video is for the alternator without an installation option feature and is done as the manufacturer recommends. Hope this helps. Happy Motoring.

[@WrenchinUpwithJimBates]

Hi - Thanks for watching and sharing your observation and opinion!

[@grahamwishart4832]

Thanks for the link. That video is about the clearest one I've seen on how to remove/install an OAD or OAP...

[@waynefoutz]

I had to replace mine on a 2002 Caravan. It took months to figure out why my belt was making so much noise. getting it off was not easy. They're torqued at a hundred pounds or more.

[@WrenchinUpwithJimBates]

+wayne foutz The impact air wrench worked pretty well when we did the video. I would imagine that would have to be used every time.

[@waynefoutz]

Jim Bates I broke my breaker bar on it. I ended up taking the alternator up too the shop I normally pay to get my major, non DIY repair done, and he took it off for me with his impact wrench for no charge. It took him about ten minutes before it finally worked it's way loose.

[@WrenchinUpwithJimBates]

Hi - Thanks for sharing your experience.

[@xVoidCypher]

Do you need a tool that grabs ahold of the shaft of the alternator and turns the shaft up into the pulley?

[@WrenchinUpwithJimBates]

Hi - Thanks for watching! It's been quite a while since this video was made but as I remember, all the tools required are included with the replacement decoupler pulley. I suggest that you check with the manufacturer. Their contact information is in the video description.

[@user-st5rc9nz4j]

My has seized up. Spins true . Can it be freed up with some oil??

[@WrenchinUpwithJimBates]

Hi, Thanks for watching! I don’t know as I have not tried that.

[@Shahidhussain30]

Great

[@WrenchinUpwithJimBates]

Hi - Thanks for watching! I'm glad you like it.

[@gulabkeerio1930]

good

[@WrenchinUpwithJimBates]

Hi - Thanks for watching! Sorry for the late reply, I missed your comment. I'm glad you like the video.

[@ghulabkhan5231]

Good morning

[@WrenchinUpwithJimBates]

Hi - Thanks for watching!

[@myviews469]

So there seems to be a delay when I spin the pulley is this normal and if this goes bad how would I know?

[@WrenchinUpwithJimBates]

Hi - Thanks for watching! Since that didn’t come up in the interview, I would like to suggest that you contact the manufacturer about this. Their contact information is in this video’s description.

[@yinelisfloresotero5838]

Hello where can I find the pice to loasen the pulley

[@WrenchinUpwithJimBates]

Hi - Thanks for watching! I think it comes with the pulley, but if not it should be available from the pulley manufacturer. I suggest that you check with the auto parts store to be sure.

[@paytongaddy992]

Hey is any mechanics available

[@WrenchinUpwithJimBates]

Hi Thanks for watching! As you probably know, there are plenty of professional technicians available. I suggest you be sure the ones you choose are ASE certified in the field of repair your vehicle needs.

[@craig7839]

can you put decouplers on alternators that dont come with them

[@WrenchinUpwithJimBates]

I'm not sure. If the shaft was threaded that might be possible, but I would like to suggest that you check with the manufacturer. Their contact info is in the comment section.

[@craig7839]

+Jim Bates Thanks, Just something to know if someone asks at the shop

[@waynefoutz]

You can, but there is no purpose. it only needs one if it's designed for one.

[@craig7839]

+wayne foutz so an older unit wont benefit from the belt running smoother

[@waynefoutz]

Craig​ I would think that the pulleys and tensioners are designed the way they are and are probably best left the way they were designed. Like I said above, Chrysler eliminated the clutch pulley on the current generation of the model I drive. The decoupler pulley, I'm pretty sure, reduces tension on the belt, so I'm thinking the tensioner has different specifications on a car equipped with the decoupler pulley. When mine failed, the spring broke inside, seizing it up, turning it into a straight pulley. This caused the tensioner to bounce, creating an awful "whomp whomp whomp" noise at idle. I'm not sure what your tensioner would do if you added the decoupler pulley when it wasn't designed for one.  I'm betting it's probably going to squeal.

[@docholliday2961]

The pulley and tool pulley will cost the same as the alternator alternators of any new car will last at least 100,000 miles .

[@WrenchinUpwithJimBates]

Hi - Thanks for watching and sharing your opinion!

[@CactusJackSlade]

Great channel.... but your intro is about 7 seconds too long 🙂

[@WrenchinUpwithJimBates]

Hi - Thanks for watching and sharing your comment!

[@OuttaHere7]

No torque spec????????

[@WrenchinUpwithJimBates]

Hi - Thanks for watching! The torque was not mentioned in the interview so I'm recommending that you check with the manufacturer for the spec for your vehicle. Their contact information is in the video description.

[@mikel5353]

Unfortunately this method will ruin the bearings, I highly Do Not recommend this method. It will ruin the bearings on your alternator like it did mine! It damaged the bearings then seized up the shaft smoked the belt and I found my self on the side of the road with an overheated motor! A new rebuilt alternator cost $250.00. If you like to risk this, use the impact or Use the Right tools and wrenches and you wont have this problem. I had to be towed home 93 miles after I waited and hour. This was not exactly what i had in mind of doing that evening!!! Using an impact on bearings is never a good idea!! This quickly became a $450 dollar mistake!

[@WrenchinUpwithJimBates]

Hi - Thanks for watching! The procedure done in the video was demonstrated by the manufacturer so I suppose it is what they recommend. But sharing your experience sheds some new light on the subject. It will be interesting to see what the manufacturer (if they respond) and others will have to say.

[@vidfuel12]

So basically a bad design

[@WrenchinUpwithJimBates]

Hi - Thanks for watching and sharing your opinion!

[@diydunder3377]

This is more of an expose.... where is the "how to" part.

[@WrenchinUpwithJimBates]

Hi - Thanks for watching! That would be the part where he shows us how to remove the old decoupler from the alternator and install the new one.

[@ColdWarVet607]

Wow! 2 so called experts using an impact to put the pulley on. Tell me, what is the torque spec and exactly how did you achieve it with 2 random pulls on an arbitrary impact gun fed with an arbitrary pressure thru an indeterminate length of hose. Id expect that level of incompetence rom the guys at the 10 minute oil change places. Very Poorly Done by both of you.

[@WrenchinUpwithJimBates]

Hi - Thanks for watching! Your comment, however, is slightly incorrect as there is 1 expert (the pulley's manufacturer) and 1 show host (me) who is by no means an expert. The procedure done in the video was demonstrated by the manufacturer of the pulley so I suppose it is what they recommend. But sharing your comment and opinion sheds some interesting light on the subject. It will be interesting to see what the manufacturer (if they respond) and others will have to say.

[@ColdWarVet607]

​@@WrenchinUpwithJimBates Really? You have an automotive/mechanical channel and your pulling the "I didn't know" excuse. I don't believe in ripping someone for a mistake as God knows I've made plenty, but there are many people watching this with little to no mechanical background wanting to save money being a DIY and following such instructions will cost them much and the damage from a jammed or broken belt can damage the engine in costs far beyond cost of the pulley and alternator. It is your channel, you are ultimately responsible for what is on it. There is no excuse or reply from the mfg because what they did was without doubt in violation of every mechanical principle on fasteners and assembly. The so called free tool included is als a huge problem and should NOT be used, more on that later, lets talk about torque.Maximum torque specs are specified by the type of fasteners material, diameter & thread type, citing a maximum torque before fatigue or failure of the fastener occurs. Torque specs for fasteners in an application can be and frequently are further reduced by the equipment designer to ensure the force exhibited by the fastener does not cause any type of immediate or long term damage to or impede/affect the operation of the device which receives the force from the torqued fastener. There is no possible way to know how much torque is placed on a fastener with an impact gun as all impact guns are different and as I stated the length and diameter of the hose dropping pressure to the torque gun. As well the fastener type, length & threads as well as the receiving fastener all affect the final torque value on the fastener. But never mind all the techno mumble-jumble I just wrote, its pretty much automotive 101 that you NEVER use an impact to tighten a fastener not just because of what I stated but also because the chance of cross threading is very high, As far as the free tool, it is free because it is incomplete. All proper tool sets for removal/installing these decoupler pulleys consist of a torque and counter torque fitting and require a 2 wrenches to remove or install. Why? Because the pulley screws onto the alternator shaft, so you can not torque the pulley to proper value on a shaft that forever turns unless some hoe you lock the shaft, just like putting a new grinding wheel on a right angle grinder, except the grinder has a switch to lock the shaft, alternators do not. Yes an impact will torque anything on a rotating shaft without rotating the shaft or barely rotating it, but the impact can destroy it all to. So the special torque counter torque tools were designed such that it can be done with a torque wrench and normal crescent wrench providing counter torque. The pulley body itself is also designed to accept the counter torque fixture of the tool, and the torque fixture slips thru it to tighten the shaft to pulley or it maybe other way. Point is its 2 pieces and requires 2 wrenches. So I don't remember if their tool or pulley is designed for the torque/ counter torque method as all other decoupling pulleys and tool sets are. Its possible they shortcut the design of both and then you must use an impact, but I'm not sure, but for sure using an impact is dead wrong, no major car service center would do that, it is not approved by or practiced by ASE or ASE Mechanics. .Please by all means have the mfg try to defend what they did.

[@WrenchinUpwithJimBates]

Hi - Thank you for the nice explanation on torqueing. I'm sure readers will appreciate that. But you are very wrong on a couple of points. First, this channel is not an "automotive/mechanical" channel (your description) it is just an automotive channel with automotive related content. Topics include Tech Talks, Shop Talks, Tool Talks, Quick Tips as well as a Back To Basics Series. Viewers, shops and auto parts store customers ask about problems and procedures and Wrenchin' Up finds someone with a solution who is willing to be a guest that provides an on-camera demonstration of their products and solutions to the problem or issue. So, there is a host (who doesn't know everything there is to know) and an expert (who is suppose to know). Sometimes only the product and/or information is provided for the host to demonstrate or explain. This formula has been well received by a great many viewers and subscribers for several years. If it is not what you think it should be, that's OK. Just don't watch the channel. You asked about having the manufacturer defend their procedure and you can do that. Their contact information is in the video description. One last thing, if you choose to "rip" anyone or anything here on this channel again I will delete your comment as soon as I see it.

[@roblaing4269]

The impact wrench method used in the video was chosen to cover all alternator manufacturers and to show the method pertaining to the tool in the OAD box. One of the popular alternator manufacturers does not use a rotor holding feature making it nearly impossible to hold the rotor to torque the OAD on. The alternator would have to be disassembled (two casting halves) to hold the rotor, as is done at the alternator factory. The preferred method was and is always torquing. This video link covers all the various types of features found on common alternator manufacturers. Litens OAD Installation: KZbin/watch?v=afjSd8YFR3A