Overrunning Alternator Pulley (OAP) Failure - How To Diagnose & Test - DIY

[@OsamahBhutta]

EXACTLY what My vw sounds like. The squeal, changed tensioner (2) and 1 idler pulley on my2.5l engine and finally found it was the altenator. Let's hope for the part tomorrow

[@mattmaring4080]

Did it work? Was it the alternator?

[@johndavidtackett]

I’m in the middle of this myself on a 2019 Dodge Grand Caravan, removed the belt and the sound went away, manually turned the alternator pulley and it’s grinding rough when I turn it instead of working as shown above. Hoping that solves the issue for me. 🤞🏻😉

[@abdlilahechibane4044]

😊😊lol

[@noneya96]

Mate I cant thank you enough holy shit did a full water pump kit and with other pullys and the other belt and then got this noise a few weeks later

[@marcusmajorov5979]

Same

[@wholelover]

My alternator pulley damaged the tensioner. Might as well replace both, so this is spot on.

[@rahimali3712]

this is exactly the same noise that I'm experiencing at the moment. thx man. going to workshop later to replace the pulley 👍

[@oliverdemirel739]

God sent video thank you so much mate most mechanic are so arrogant they won't agree with this 😂

[@noel5ilv3rlake]

It has been happening to my TT BAM , the clank noises but yeah Not belt, accidentally the neighbor garage mechanic told me :” man the timing belt is in trouble, maybe I can help you out!”. But, I decided to bring my car home to my own garage I’m not a mechanic but I don’t want to get bill horror, ordered Tensioner and SKF Pulley online from trusted store and it was cheaper too but the inside the box was INA OE 😂, Removed the alternator that was not so hard, used electric impact gun+spline 33 I did in a second 😢 NOW the car is sounding like a new without horrible noise or clank or flapping belt I’m glad ! I did myself 😅 Btw your Vid will help everyone’s 👍

[@ramiromaldonado1025]

I have been paying mechanics already for find me the noise they told me it was a water pump the AC and bearings and I got tired and I took my car home thank you for your help how to check the alternator

[@MiracleMAX]

Well done mate - it is often misdiagnosed.

[@GerardBurkeBurkesGarage]

Cheers mate

[@shaolin224]

I here the squeal in my car when it rains. But then I heard it when it wasn't. Took a closer look at the pulley and it's shiny like the belt slips on the pulley due to maybe the bearings are starting to seize. I not a mechanic but do you think it's going bad?

[@kahlaaja]

Gosh I might have this in my bmw E87 - With Clima off the only device on my belt drawing power is the alternator and the belt whines and tensioner bounces just like this! Gotta go now investigate. Whether it was or not: Thanks for the knowledge! : ) Edit: I may have had it temporarily stuck as this appeared after the car was un-driven for a month waiting for timing chain fix. I took the belt off and tested the alternator pulley, and it seemed to be ok as all of the other pulleys (very un-expected). Put the belt back and started the car, and the engine was just smooth and quiet LoL :D

[@knolez1546]

Thanks man. I thought it was my tentioner. I took the belt off to check and it was fine. Now I know to check the alternator pulley. Thanks

[@Travis-k5g]

Hey dude , on a 8 year old ford ranger 3.2ltr . Should the whole alternator be replaced or just do a new pulley fitted to the old alternator ?

[@Toni-rx8hh]

Can this also make problem for charging battery? My Alternator Pulley wont rotate smooth on the other side when I insert screwdriver. But alternator is good, I checked it.

[@royabbott2356]

I understand with technology, mechanics on engines change. But on the older cars with a normal alternator pulley..there was never an issue about an alternator overrunning. Now people say replace it as soon as the clutch pulley does not work. Maybe on higher revving petrol engines it helps, but on diesels which operate between 800 and 4000 is it really necessary? What can happen if you dont change it...nothing perhaps?

[@lucifer9033]

Just fixed my car after watching this. Thanks! :D

[@dayahdiva78]

How did u do it? please help

[@silasatlas3835]

I simply replaced the solid alternator to a clutch pulley alternator which stopped the belt bouncing and tensioner bounce and now have a smooth running quieter engine

[@gusbus007]

Is a Overrunning Alternator Decoupling (OAD) same thing same issue?

[@fatboy300hemi]

Thank you for this information you saved me so much headache. You is awesome!

[@ralphjackson888]

Is it ok to drive for a few days until I can replace it. Over run pulley is engaged both direction 2019 grand caravan

[@melanierosemonajan5216]

Did you replace the tensioner pulley? It's look different from the start of the video compared to end of video..

[@dobridimitrijevic2718]

only when starting the engine, a short whining sound is heard and it is no longer there. the pk belt and the pk belt pulley were replaced. could the floating pulley of the alternator be the cause?

[@barrygray8356]

Must you take the belt off to test? Can you just poke a screwdriver to the fins of the alternator to see if it spins in one direction only and not both directions. Its quite hard to take the belt off lolz.

[@dez945able]

i hi, I have a past b5 it looks like I have the same problem, want to ask should change the Tensioner, as well or just Alternator Pulley

[@babelonchabalala1690]

Had a VW T5 minibus with V-belt tensioner ripped apart as result of a failed alternator clutch pulley....... Tensioner was jumping up and down on the belt and eventually made it slip off and tore into pieces.... New tensioner and 3 belts later decide to change this alternator pulley..... nightmare taking it off the engin..... the machine shop luckily removed the pulley and put new one for free with their special tools..... now problem is solved .... no more tensioner and belt jumping or vibrating ;)

[@denzelcrocker4956]

Hello, If i look my alternator, it locks properly to the right side. It can turn to the left Side, but makes grinding noises

[@adversaryforu9814]

Hi, is it possible to spinn the alternator by hand when it's on the car without taking of the belt? Let's say that if I try to spinn the blades?

[@migano666]

of course, you can try to rotate the blades in direction of belt or to rotate the alternator rod - inner center of pulley, usually hex, allen key etc. I am driving with stuck pulley already about ... more than year, no bouncing belt. But I know that it is bad for main (chrankshaft) pulley - rubber part.

[@celticmad66]

I have an Audi a2 Tdi with a weird warbling noise on idle rev it it goes away and if you turn steering slight it briefly stops , steering fluid is fine , could it be this. ?

[@dararoth3979]

Hello sir! Now my car meets this problem. Thank your for your explain.

[@dot3596]

Mine started doing the same. Incresses when i turn the steering while still

[@niksugden5425]

Definetely sounds like mine on the amarok. Is this safe to drive for a short distance. Im about 10- 15kms from a workshop

[@deank3727]

Hi unrelated question sorry 😐 I have a oil leak Toyota auris 2007 1.6 petrol chain tensioner is leaking oil lossing 250ml of oil every 2000k any advice on setting the chain tensioner back in its correct position and not destroying my engine thanks love the video s 👍👍👍👍

[@AndrewEvans-us6mv]

Happened on my vw scirocco tdi drives like new now 🙏🏼😎🤛💥❤️💛💚

[@davebarnett3809]

Mine moves freely in both direction when I use the screw driver to jam it

[@GP90210]

My dealership misdiagnosed the tensioner, wanted $400 for that one part to be replaced. It was not that, it was the alternator. It is a good idea to replace the tensioner if you are doing the job yourself. The part is inexpensive.

[@GerardBurkeBurkesGarage]

Yes it is a good idea usually depending how long it has had that additional stress. Not always required but recommend in most cases 👌👍

[@VintageLynx]

Plus easy to get to with alternator removed.

[@Sven_Re347]

I have an electric powersteering and everytime I steer the belt slips because it asks allot of current. The OAP pully is also broken I guess.

[@castrolgtx5064]

Hi Ger Speaking about clutch’s have you ever fitted one that was faulty? And had to take the gearbox out again.. I’ve a 2012 Kia Ceed 1.6 dsl and there’s a wicked vibration through the car when you accelerate, I fitted a Sachs thinking I’d never see it again they have a good name but apparently for German vehicles mostly. I was told Valeo only for the Korean cars they are a softer clutch.. this is no small job as you know I’ve to drop sump frame again etc etc Have you come across this during your career? Thanks Ger🔧💥

[@GerardBurkeBurkesGarage]

Hello Eric, The answer to the first part is yes, I have fitted clutches and had to go again due to parts issue. In my example it was a faulty valeo clutch plate on a mondeo that would not release properly after engagement (thats different to your question) Any vibration issues I have had have all been flywheel related and not the clutch. Was the vehicle driving before had and if yes was there any vibration present in the road test?

[@castrolgtx5064]

@@GerardBurkeBurkesGarage They said it definitely wasn’t in the car before… only after the clutch replacement, they had the car back 3 weeks and then contacted me about the issue. Also it is fitted with a solid flywheel not Duel mass, I’ve doubled checked everything including the driveshafts for wear.. a bit demented from it to be honest I got a mechanic friend’s opinion after he test drove it he reckoned a broken spring in the clutch Disc. They are honest people the owners of the vehicle so I just have to take their word about this issue wasn’t in the car before the repair. Yes the car was driving before hand Ger., also it would only do it on acceleration around 40 -50 miles an hour when there was a load on it the second you leave off the pedal it stopped

[@sitatt]

Cheers, mate! Good fix!

[@shanemcgovern2204]

Another great video,great detail

[@GerardBurkeBurkesGarage]

Thanks Shane, very much appreciated 🙏👌👍

[@jamesclancy2152]

Top stuff. Thanks for the info

[@2WheelSam]

Great video thank you

[@petar443]

Thanks for the video 🥃

[@GerardBurkeBurkesGarage]

Thanks Petar 🙏🙏

[@LOTPOR0402]

How can that be right when you stop pedalling the bike the chain stops moving .In a car the belt never stops moving and is always running one way ?

[@bruiladebeen5671]

When lowering revs the mass off the spinning alternator doesn't slow down without creating tension and vibration in the belt when this overrunning pulley doesn't work.

[@kingGar27]

UPDATE: SEE @Davesworld7's REPLY BELOW FOR A DETAILED EXPLAINATION OF HOW OAP'S WORK. In short, the reason for free wheels on alternators and AC compressors (which typically use a clutch type setup, but with the same purpose) is so that those components aren't always taking power from the engine (a) when the battery is not being charged and (b) when the AC is not turned on. Without the freewheel, there would be a constant drag on the engine, even when the battery is fully charged and the AC is off. So it saves on fuel and gives the engine a bit more power when those items are not in use. Good video.

[@Davesworld7]

This is incorrect. The alternator pulley is overrunning because the heavier armature of high amp alternators tries to overrun since the engine speeds up and slows down during each revolution, an engine does not turn at a constant speed within each revolution. The heavier armature of a 240 amp alternator can even pop the belt off without a decoupling pulley and will certainly cause vibration. The alternator is never disengaged with a decoupling pulley as the case would be with an AC Compressor clutch, it is 100% mechanical. You can turn it by hand in one direction but not the other so that during each slowdown that happens within every 360 degrees, the heavy armature temporarily goes faster than the belt multiple times each revolution. The alternator is ALWAYS putting something out because you are running things like ignition, blowers, computers, and so on. The alternator output is changed by the amount of current applied to the field based on load and alternator drag varies with how much field is applied, it has nothing whatsoever to do with an overrunning pulley. In modern engines, the field is controlled by the ECU. If an alternator is being asked to produce the full current and the field is fully powered, it's like trying to turn an electric motor backward against itself. How you think it is like an AC clutch escapes me. There are no wires to an overrunning pulley. It threads right onto the shaft. I use them, have had them in my hands, and so on. While they have a clutch in them, it's basically like a one-way clutch and once again the alternator ALWAYS spins 100% of the time.

[@kingGar27]

@@Davesworld7 Ah OK, I misunderstood the reaoning behing the alternator pulley. Your explanation make sense. I thought OEMs brought out alternator pulleys that had a clutch-like mechanism to do as I described (i.e., halt electricity generation when battery voltage is high enough) in order to inmrpve engine efficiency. Perhaps I am mistaken though.

[@crisdlq887]

Haha I have been done with this. They have tried to get me to rectified the head gasket, pistons etc , it turns out it was only the alternator clutch

[@patkelly7999]

Good job Gerard, Thank You:):)

[@GerardBurkeBurkesGarage]

Thanks Pat, as always it is much appreciated 🙏🙏🙌👏

[@edwarddecastella884]

you champion mate

[@jameshalligan1933]

As a garage you should know the pulley is a replacement item I’d be quite alarmed if you changed a alternator just because the clutched pulley failed but good way to exploit more money from a customer

[@GerardBurkeBurkesGarage]

James, its in the video, check the 5 minute mark, no need to be alarmed 👍

[@jameshalligan1933]

Sorry buddy my bad 🇮🇪

[@GerardBurkeBurkesGarage]

@@jameshalligan1933 all good 👌

[@shemmo]

you dont need to change the whole alternator, you can buy and replace just the pulley.. side note - you will need a special tool to do it, but is is not expensive.

[@GerardBurkeBurkesGarage]

Information is in the video at the 5 minute mark onwards. Depending on pulley type you may not even need the special tools. Lots of options available to decide. In this case the customer wanted the alternator changed. Whatever works for you, the information stays the same

[@kirwanjohn101]

@@GerardBurkeBurkesGarage Best option was to change the alternator with a refurbished one. I bought the clutch pulley and tool to remove it then when I had it removed found that I couldn't remove it as it was too tight. I had an impact gun but could not get it removed. Then I went to an alternator repair guy. He fitted my new clutch pulley, changed the bushings and charged me almost the same price as a new one! leason learned the hard way. If you decide to remove the clutch pulley you will need an air gun. Trying to remove it on a vice with a corlesss impact gun in my case didn't work. So my advice to anyone other is simply to replace the unit, if you search on line you can get a fully refurbished one quite cheaply.

[@Antimortem]

Thanks 💐

[@GerardBurkeBurkesGarage]

🙏🙏👌

[@mariglenqendraj304]

Thanks

[@rikkioconnor5450]

why would you change the whole alternator when you can just change the pulley

[@GerardBurkeBurkesGarage]

*Low cost alternator. *Pulley shaft damaged. *Alternator not charging 100% *Addtional labour makes the overall very similar. *Customer decided too. *Part not available. *Special tool not available. Any of those reasons can lead to the alternator getting replaced. Thanks for watching Rikki 👍

[@grahamwells1774]

🔥

[@bengatss]

When engine stops, belt stops, then alternator clutch pulley comes in..

[@marcass100]

legend

[@p.istaker8862]

Stick the crap in the bin along with dual mass flywheels, canbus and electronic parking brakes

[@vutrengteng3164]

If you have this problem, just weld it.

[@dayahdiva78]

Can someone help explain to me what exactly I’m supposed to buy and how much does the labor normally cost to have it installed?? I’m have this exact problem with my 2020 rav 4 xle

[@sitatt]

Thanks!

[@GerardBurkeBurkesGarage]

Thank you very much, 🙏🙏