V6 SOHC; Belt Tensioner Rattles Occasionally

[Metalface]

The belt tensioner(?: top left/passenger side of motor in belt assembly,) rattles occasionally. It is noisy as hell but it's been going on forever. I am 100% sure it's not chains.
It rattles when the AC is on, it rattles when the alternator is working (usually when the truck first starts up, or if I've ran the battery especially down with lights and other accessories. I've also noticed one time I accidentally let my battery go flat, the rattle went for until the voltage showed normal on the battery gauge.) and that is the only time it rattles. We put a popsicle stick between the gap in it, where it rattles upon itself, and the noise entirely went away, so I am sure it is that. It is not chains.

Is there a common "problem" belt driven part.. That I should be looking into? Thoughts + suggestions all welcome!

Please ask me tons of questions so I don't overlook something that I probably am overlooking at the moment lol, thanks everyone

Edit: Turns out tensioner was replaced about a year ago so the tensioner is infact newer. Not sure what brand part, aftermarket vs oem, was used however.

 

[C420sailor]

Tensioners should be replaced regularly, along with the serpentine belt.

I do mine every 100k, along with the belt. I’ll replace it sooner if it’s starting to make noise.

 

[J_C]

Yeah I don't understand, if the tensioner seems to be making noise, time to replace it?

 

[Metalface]

Yeah I don't understand, if the tensioner seems to be making noise, time to replace it?

Well, you see.. Neither do I... hence why I'm asking lol. Ok, I was unsure if it was a replace-often thing. It is fine until times like that. I was a little fearful that if I replace it with what would in theory be a healthier more robust brand new tensioner, if I have a dragging pulley or something, it might make less sense than replacing what is wrong. In essence that it might finish off whatever may be going bad that I haven't found in my previous investigating.
I was wondering if this is a symptom of a commonly known ailment for any of the parts of the belt driven assembly, but I guess not.
(Drag from other failing part, that may be a common problem that someone here could tell me about = rattling tensioner..? Suppose not then!)
Works for me lol, I've got 220k now and I got it at 160?k. I had assumed it must have been replaced recently enough until the past year+ish, because it wasn't always making this noise. I suspected maybe another part was failing causing drag causing it to make noise, but in that case, I will replace the tensioner first and see what I get. Thanks!

 

[C420sailor]

60k is a little low…I had one start to go around 80k. But it depends on how much idling and stuff you do—it doesn’t translate directly to mileage well

Higher quality ones tend to do better

 

[Metalface]

60k is a little low…I had one start to go around 80k. But it depends on how much idling and stuff you do—it doesn’t translate directly to mileage well

Higher quality ones tend to do better

Agreed! I feel like maybe the previously dying alternator played a part in wearing it out. It certainly did take a complete **** on me, so I wouldn't be surprised if it wore out the tensioner a lot faster than it should have worn under regular conditions. I suspect my AC clutch is kinda ****ted out, it whined when I first got it, but I can't say what shape it was in because I never investigated it as long as it just worked. Not to mention I'm one of those psychopaths that are ok with not even using AC and having all the windows down all year long if I'm hot. Nuts, right. Hahahahah.
Can't really say it's quiet now either because the tensioner rattles when the AC is on... lol
I don't let it idle much, it has a tiny misfire but only after it's been idling a few mins (gotta get those injectors done) and I just rather not idle it unless it's to cool down after a long trip.
But you're totally right and I agree w/ mileage #'s aren't the only thing to go by, I mean, case and point right lol. And yeah.. Poor man buys twice. If it's a problem especially I'm going to go for OEM or "upgraded with real reviews" for parts. Ty!!

 

[C420sailor]

“Buy once, cry once”

 

[J_C]

Ok, I was unsure if it was a replace-often thing. It is fine until times like that. I was a little fearful that if I replace it with what would in theory be a healthier more robust brand new tensioner, if I have a dragging pulley or something, it might make less sense than replacing what is wrong. In essence that it might finish off whatever may be going bad that I haven't found in my previous investigating.
I was wondering if this is a symptom of a commonly known ailment for any of the parts of the belt driven assembly, but I guess not.
(Drag from other failing part, that may be a common problem that someone here could tell me about = rattling tensioner..? Suppose not then!)
Works for me lol, I've got 220k now and I got it at 160?k. I had assumed it must have been replaced recently enough until the past year+ish, because it wasn't always making this noise. I suspected maybe another part was failing causing drag causing it to make noise, but in that case, I will replace the tensioner first and see what I get. Thanks!

Replacing a bad tensioner with a good one, or even a marginally-good one with a more fit one, won't cause anything else to fail sooner.

If you think something else might be dragging, take the belt off and rotate pulleys by hand, checking resistance but especially wobble.

I am not sure what to make of what you wrote, the "I had assumed it must have been replaced recently enough... because it wasn't always making this noise" ? I mean, how does that differ from it possibly being the now 26 year old factory tensioner that has simply worn out but is dying slowly from a weak spring or worn bearing? Do you have vehicle records indicating it was replaced and if so, when?

Extra drag should bog the engine down a bit, depending on how bad the drag, not cause the tensioner to make noise. There may be a little arrow cast into it which is not 100% proof but if the arrow isn't far enough to the side it's putting tension on (another arrow cast? I forget), it is a sign it is worn out. Also the amount of belt deflection when you push on it can indicate whether worn out. IIRC one rule of thumb is 1/64" deflection for each 1" span (between pulleys) where you measure.

Maybe I'm misunderstanding but I don't see in your post where there is evidence this tensioner was replaced near 60K miles ago, if ever. Either way, median quality or better tensioners are not expensive compared to most parts, are a potentially DIY repair, and might as well eliminate that if it's been at least 60K mi and maybe the entire life of the vehicle depending on what I wrote above, not knowing the situation.

 

[Metalface]

Replacing a bad tensioner with a good one, or even a marginally-good one with a more fit one, won't cause anything else to fail sooner

No, obviously. I mean that if something is currently broken and causing a lot of drag and if there are no common obvious parts that will fail and cause a lot of drag, since everyone is saying that is not the case there is no obvious culprit that can be identified other than just the tensioner itself.. That by replacing it it would take out whatever I was concerned about in a potentially catastrophic fashion. But everyone has already explained that there are no parts that just go bad and cause drag like this, so I'm just replacing the tensioner itself.

And yes, I know to check things by hand if I am concerned. Had the belt off when I did the alternator and idler, everything felt alright, but that was a while ago.

I am not sure what to make of what you wrote, the "I had assumed it must have been replaced recently enough... because it wasn't always making this noise" ? I mean, how does that differ from it possibly being the now 26 year old factory tensioner that has simply worn out but is dying slowly from a weak spring or worn bearing? Do you have vehicle records indicating it was replaced and if so, when?

Well, considering it was a fleet vehicle in another life.. They do tend to go by the book for mileage based repairs.
Don't have records showing explicitly when the tensioner was replaced, however, it was definitely babied before parked, and the oxidation on other parts near the tensioner vs the tensioner itself is much greater than what is on the tensioner. It appeared to be in better shape than some of the other parts around it. I don't know if you live in a salt area, but this truck is from the salt belt and the coast, so it is easy to tell visually if something is older than something else if they are next to each other and made of the same metal.
If I had records specifically showing when the tensioner was replaced, I wouldn't really be wondering or trying to find out if there is a common culprit part that causes significant drag when it's going bad that I won't hear or notice in any obvious way before disassembling to investigate, hence why posting on this forum full of people who own the same vehicle.. You know..

Maybe I'm misunderstanding but I don't see in your post where there is evidence this tensioner was replaced near 60K miles ago, if ever. Either way, median quality or better tensioners are not expensive compared to most parts, are a potentially DIY repair, and might as well eliminate that if it's been at least 60K mi and maybe the entire life of the vehicle depending on what I wrote above, not knowing the situation.

No, I did not think that it was replaced 60k ago. I said I got the truck at 160ish thousand miles and now on at 220k.. But nowhere did I say 60k, I don't know where you're seeing that..

Extra drag should bog the engine down a bit, depending on how bad the drag, not cause the tensioner to make noise. There may be a little arrow cast into it which is not 100% proof but if the arrow isn't far enough to the side it's putting tension on (another arrow cast? I forget), it is a sign it is worn out. Also the amount of belt deflection when you push on it can indicate whether worn out. IIRC one rule of thumb is 1/64" deflection for each 1" span (between pulleys) where you measure.

That was helpful, I will be checking that and thank you for the info!

 

[C420sailor]

Fleet vehicles…depends

They often do the manufacturer suggested service religiously according to schedule, but everything else is often ‘if it ain’t broke, don’t fix it’

Depends on the company and fleet services shop, though. OEM tensioners do tend to last a long time…if that’s a Ford tensioner (I think they stamp the Ford oval on them) it may be original…but that would be an epic run. So who knows.

The two big draggers are the AC compressor when the clutch starts to go, and the bearings in the alternator. PS pumps…not so much, in my opinion.

Idlers are easy to replace if the bearings start to go

 

[Metalface]

Fleet vehicles…depends

They often do the manufacturer suggested service religiously according to schedule, but everything else is often ‘if it ain’t broke, don’t fix it’

Depends on the company and fleet services shop, though. OEM tensioners do tend to last a long time…if that’s a Ford tensioner (I think they stamp the Ford oval on them) it may be original…but that would be an epic run. So who knows.

The two big draggers are the AC compressor when the clutch starts to go, and the bearings in the alternator. PS pumps…not so much, in my opinion.

Idlers are easy to replace if the bearings start to go

Oh, I totally agree. But, 220K on the original tensioner? Possible but I think very unlikely.
Well, since I did the PS, alternator, idler pulley... It's the AC clutch if there's extra crazy drag. I've got a feeling my tensioner might be ok, but the AC is causing drag, but I definitely don't want to dive into that if that's the problem. Gonna replace the tensioner and see what I get! I will check what others suggested to check to see if it's actually doing its job first though. I'm assuming it's not, however.. We will see

 

[410Fortune]

Okay remove belt spin pullies check for looseness or wobble in any of the pullies
Any odd noises or grinding when spinning means the bearing or pulley needs replacing. Alternator power steering should spin smoothly. Waterpump should give a little resistance but should not have any up down or in and out play

Common check done anytime there is a belt noise or worn pulley, this is routine maintenance

 

[Metalface]

Okay remove belt spin pullies check for looseness or wobble in any of the pullies
Any odd noises or grinding when spinning means the bearing or pulley needs replacing. Alternator power steering should spin smoothly. Waterpump should give a little resistance but should not have any up down or in and out play

Common check done anytime there is a belt noise or worn pulley, this is routine maintenance

Indeed! +1

Once again asking other than the obvious. Are there any well-known parts that are belt driven that fail often that I should be looking out for.
Like how if the engine stops working it's usually the timing chains; "oh, those damn timing chains. Always the timing chains."
Nothing?

 

[410Fortune]

Well yes the thermostat housing the waterpump are good to replace around 100-150k miles everything else is “as needed”
We regularly see sohc engines with 200-300k on them around here people who are really good at changing their oil and maintenance will get more

 

[Metalface]

Well yes the thermostat housing the waterpump are good to replace around 100-150k miles everything else is “as needed”
We regularly see sohc engines with 200-300k on them around here people who are really good at changing their oil and maintenance will get more

Yes! Thought as much; I've done my homework lol. Lurked here for a long time and referred to other resources before that.
I will check the thermostat and waterpump. I have heard they are finnicky, and friends of mine have had issues with theirs though I have not. Mine never seemed problematic but I know that although something is working it doesn't mean it isn't tired. I change my oil at 3k, because of reasons well known to SOHC owners lol, among other maintenance. Good tip! Thank you.

 

[C420sailor]

Water pumps are usually pretty good. The plastic thermostat housings are the problem children

 

[Metalface]

Water pumps are usually pretty good. The plastic thermostat housings are the problem children

Noted. Heard that before but not something I've committed to memory.. Until now haha. Thank you

 

[Metalface]

Update: girlfriend (we share the truck) informs me her and our friend who collects old Fords of varying degrees of quality actually replaced the tensioner a while (probably a year) ago. It's a bonding thing, proud of her lol
I asked her which brand part she used out of curiosity, she said probably the original. I said "But gf, you thought Motorcraft was like Duralast when we went to Autozone last time.." -- she literally said, "no, I don't want Motorcraft.. I don't want an off-brand. Duralast is a good brand, though." me and the cashier just gave each other a look and started laughing. Gf is lucky she's cute. So, she really would not know which grade of part she replaced it with. I could call Mark but he wouldn't remember by now hahah... LOL The mystery continues. I knew I wasn't crazy looking at that tensioner seeing it looked pretty new. But it also looked pretty new when we picked up the truck to begin with. Maybe they threw parts at a problem and couldn't solve it, that would be my luck wouldn't it.
So overall I suppose good news and bad news.

So that being said, place your bets on which pulley/belt driven component is dragging, and perhaps why..... lol. I'm betting the alternator I put in is a little funny, or maybe my battery is taking a **** even though it reads good under a load tester. I've got so much going on with other stuff right now haven't had the belt off. But that was a nice little information nugget I got this morning, sigh lol

Upon reading other threads (most of which went unanswered.. nice,) others who had the issue suspected belt length among other things.
I am going to try to also get a new belt. I would not put it past a previous owner to put on a "close enough" belt if that is even possible.
Is that even possible? I'm assuming no but you'd be amazed what people can **** up in a pinch.

Does anyone have a go-to brand or part# for belt for the stock V6 SOHC for 97 model year? (I don't think they are different if at all for belt length but since I've never had to deal with that, I could be totally wrong in that assumption.) On other vehicles I would usually just get whatever belt, but I also never had issues like this and I want to do everything as correct as possible to eliminate variables when I do perform the job so it is done the right way the first time.
And for all I know, the belt was replaced by gf and our friend at some point, I wouldn't put it past them but she nor I remember if it was. It is healthy looking, I can say that at least, but that isn't the focus right now. So I'll continue to assume that it may be the belt being wrong or something silly, in addition to I'm assuming something is causing drag in the belt assembly, before I take the belt off, just to maybe put off the same bad belt again potentially if it turns out nothing is dragging. Better safe than sorry or wasting time IMO

Edit: And can the tensioner rattling (I guess clearly showing too much tension on belt driven assembly) be a sign that I'm about to lose a belt or something? I'd imagine yes, but I've never experienced that either.

 

[donalds]

Back in 2014 I had this problem
After a few tensioners
I simply bought a shorter belt

Mine only made clicking type sounds with the AC on

 

[donalds]

Back in 2014 I had this problem
After a few tensioners
I simply bought a shorter belt

Mine only made clicking type sounds with the AC on

used a dayco #5060860 will put your tensioner in the middle of its range check where the tensioner range is at

Symptoms were clicking tensioner squeak ing belt
Here is a good read Belt length causing tensioner rattle

I found a old post of mine