Serpentine Belt Tensioner Rattling

[Kevinlow831]

Hi all, does anyone have any ideas on a fix for this?

My belt tensioner is chattering/rattling, only at idle while in Drive, i.e stopped at lights. Rattling stops when you rev up or drive.
Seems load related on the engine.

I have tried 3 different tensioners. All made the same or similar noise.
3 different belts, final one on the car now is a genuine Motor craft belt. I really thought this was the issue as it was a little shorted than other belts feted. Motorcraft part number JK6455-D.

Also replace the compressor pulley, because the coil pack failed. so this is new with new bearings
This noise was evident before anything was replaced.

Is there a harmonic damper/resonance damper in the crankshaft pulley?

Only other pulley is the alternator which spins freely and is silky smooth.

Any help appreciated or anyone who has experience and fixed this willing to share the magic

Many thanks

 

[Steve8316]

My belt tensioner is chattering/rattling...
I have tried 3 different tensioners. All made the same or similar noise.

Then it's probably NOT the tensioner making the noise. It's probably coming from inside the timing cover. How many miles on the chains/tensioners/guides? You should put more useful info in your profile (you can leave out "Explorer" since that's the name of this forum), and in your signature.

Also replace the compressor pulley, because the coil pack failed.

A coil pack is for the ignition system, and these engines don't use coil packs - they use coil-on-plug (COP). The compressor clutch uses an electromagnet.

so this is new with new bearings

New is meaningless. New parts can be bad - especially aftermarket. What brand is the new pulley, and who installed it?

Is there a harmonic damper/resonance damper in the crankshaft pulley?

The crank pulley IS the harmonic balancer. It has no moving parts.

 

[J_C]

Is there a harmonic damper/resonance damper in the crankshaft pulley?

It has a permanently bonded rubber portion, you'd just replace the whole thing if the rubber is shot.

Backing up, have you tried momentarily running the engine without the belt, to be sure it is the belt system? Does spraying water anywhere quiet it down, if you're careful to spray only one at a time?

 

[Kevinlow831]

Then it's probably NOT the tensioner making the noise. It's probably coming from inside the timing cover. How many miles on the chains/tensioners/guides? You should put more useful info in your profile (you can leave out "Explorer" since that's the name of this forum), and in your signature.

A coil pack is for the ignition system, and these engines don't use coil packs - they use coil-on-plug (COP). The compressor clutch uses an electromagnet.

New is meaningless. New parts can be bad - especially aftermarket. What brand is the new pulley, and who installed it?

The crank pulley IS the harmonic balancer. It has no moving parts.

Hi, The noise is from the tensioner, you can see it rattling/vibrating and when load is removed from the engine the vibration decreases and the noise goes away
Mileage is just under $130,000. timing chain is not rattling as this is a distinctive rattling noise.

I installed the tensioner. I am a time served vehicle technician for over 25 years in the UK. Now live in sunny Florida. The Explore and this engine we did not have in the UK.
I fitted a generic tensioner twice and then fitted a Dorman one which I believe is a reputable brand of good quality. My thoughts were if the crankshaft pulley is the harmonic balancer I know on many other brands these can fail and stop absorbing engine and transmission vibrations

will try and update my profile to reflect more info

 

[Kevinlow831]

Hi all, does anyone have any ideas on a fix for this?

My belt tensioner is chattering/rattling, only at idle while in Drive, i.e stopped at lights. Rattling stops when you rev up or drive.
Seems load related on the engine.

I have tried 3 different tensioners. All made the same or similar noise.
3 different belts, final one on the car now is a genuine Motor craft belt. I really thought this was the issue as it was a little shorted than other belts feted. Motorcraft part number JK6455-D.

Also replace the compressor pulley, because the coil pack failed. so this is new with new bearings
This noise was evident before anything was replaced.

Is there a harmonic damper/resonance damper in the crankshaft pulley?

Only other pulley is the alternator which spins freely and is silky smooth.

Any help appreciated or anyone who has experience and fixed this willing to share the magic

Many thanks

Just to add in for help. When i fitted motorcraft belt JK6457-A which I ordered from a Ford OEM parts site. This belt was supposed to fit my Explorer. This made the tensioner rattle so loudly like it was clanking like someone was hitting a hammer against a piece of metal. When I swapped out the belt to the current one the noise went but now only make the noise when idling, in Drive with AC on.
If you put the car in Neutral the noise stops. If you switch off the AC the noise stops. As soon as you rev us slightly the noise stops.

 

[J_C]

I don't know if it matters, but the Dorman tensioner listed on Rock Auto states Pulley Bearing Diameter (MM)61.5 mm, while RA shows the Motorcraft BT97 has outside diameter 2.76", which would be 70.1 mm. Belt JK6457-A is for the heavy duty alternator on RA's listings, but I would've thought yours would have the heavy duty alternator being a Limited, but I don't know that for certain, or even if it still has the original alternator.

Is the engine lugging at low RPM when this noise happens? There's a Ford TSB 15-0149 for low idle with A/C on and the 3.5L NA, but that TSB was only for 2013-2015 model years.

 

[Steve8316]

The noise is from the tensioner, you can see it rattling/vibrating...

No, I can't see it. And I don't believe you can see sound, either. But if you believe you can - GLWT. I agree with J_C: you should remove the serpentine belt and run the engine to check if the noise is still present. If it's not, spin each of its pulleys by hand to check for noise & looseness. Also, clean out the grooves of the belt & pulleys so it has a chance of moving smoothly.

I fitted a generic tensioner twice and then fitted a Dorman one which I believe is a reputable brand of good quality.

No, Dorman isn't a quality brand - it's just the best of the worst imported junk.

 

[BrettS.]

Dorman is not known for quality. I would get an OEM tensioner. Dorman is what you buy when an OEM part is not available. The quality of parts has gone downhill drastically in the past 5 years.

 

[Kevinlow831]

No, I can't see it. And I don't believe you can see sound, either. But if you believe you can - GLWT. I agree with J_C: you should remove the serpentine belt and run the engine to check if the noise is still present. If it's not, spin each of its pulleys by hand to check for noise & looseness. Also, clean out the grooves of the belt & pulleys so it has a chance of moving smoothly.

No, Dorman isn't a quality brand - it's just the best of the worst imported junk.

Thank you for the Dorman info I did think it was better quality, but am misled. Hard to believe 3 tensioners made the same noise though.

As for seeing sound. Guess thats an experience thing when you look at where a noise is coming from and see something vibrating you see where the sound coming from. Its like knowing a suspension knock location when driving the car. experience just points you in the right direction as car make certain sounds depending on what the car is doing at the time
I did not expect the sarcastic comment! Thanks for that.

I will run the car without the belt just incase. Alternator pulley spins ok and looked good. AC pulley is new and the noise was there before I replaced this pulley

 

[jwolfe]

Only put Ford parts on a Ford. Aftermarket stuff is crap. Ford oil, Ford plugs etc etc. Nothing goes on mine except OEM.

 

[J_C]

^ Seems a bit overkill, there are a fair amount of quality aftermarket parts, but certain aftermarket suppliers who deal in too many parts like Dorman or Beck Arnley (and AC Delco to a lesser degree), are importers from various manufacturers and the quality from part to part can vary, while a 3rd party brand that makes parts, focuses on their forte and some are even the same manufacturer that made the Motorcraft part, but without the Motorcraft OEM price markup.

I disagree about oil, plugs, and many other items. It's not that Motorcraft makes bad parts or fluids, but often are no better than other brands costing less. The main thing is not to buy generic parts and look around or ask what experiences others have had with brand X for part Y for vehicle Z.

 

[jwolfe]

Motorcraft oil is dirt cheap in bulk and designed for the engine. I’ll pay the extra few bucks to know I have a quality part. I often source used parts of new ones aren’t available. I’ve had more than one alternator rebuilt. Im not going to put Autozone junk on my unit when I depend on it to work when I need it.

 

[J_C]

Motorcraft oil is dirt cheap in bulk and designed for the engine. I’ll pay the extra few bucks to know I have a quality part. I often source used parts of new ones aren’t available. I’ve had more than one alternator rebuilt. Im not going to put Autozone junk on my unit when I depend on it to work when I need it.

Motorcraft oil is designed for WHICH engine? Motorcraft synthetic blend is fine for these vehicles, but not at all the best, and not the best bang for the buck either.

It would take a somewhat severe duty service to need more than the Motorcraft blend, but make no mistake that it's a higher cost:quality ratio than can be had from most other brands that actually make the oil instead of buying someone else's oil and just adding their middleman markup to it like Motorcraft does.

I can appreciate buying a Motorcraft alternator for your generation of explorer because that generation is known to have some problems using aftermarket alternators but if we want to generalize, there are aftermarket rebuilt alternators that work fine, it's just more of a gamble on other generations of explorer. I happen to be someone who won that gamble (so far), that my Autozone alternator for my '98, is working fine 10 years later, and has a lifetime warranty. It also cost less than half what the Motorcraft does. I wouldn't have bought it if I long tripped my '98 but it's day for doing long trips is over.

I'd feel a little bit better about Motorcraft parts at their higher price if they at least offered a lifetime warranty on anything that isn't a wear part like shocks. If buying motorcraft helps you sleep better at night, then that alone is worth it, but not everyone is in that situation. It's also a little offense to me that they buy parts in bulk and then mark them up (as much as they do) for extra profit to sell to their customers. They should try harder to raise their customer satisfaction levels by keeping their prices more competitive.

 

[jwolfe]

Motorcraft oil is designed for WHICH engine? Motorcraft synthetic blend is fine for these vehicles, but not at all the best, and not the best bang for the buck either.

It would take a somewhat severe duty service to need more than the Motorcraft blend, but make no mistake that it's a higher cost:quality ratio than can be hand from most other brands that actually make the oil instead of buying someone else's oil and just adding their middleman markup to it like Motorcraft does.

I can appreciate buying a Motorcraft alternator for your generation of explorer because that generation is known to have some problems using aftermarket alternators but if we want to generalize, there are aftermarket rebuilt alternators that work fine, it's just more of a gamble on other generations of explorer. I happen to be someone who won that gamble (so far), that my Autozone alternator for my '98, is working fine 10 years later, and has a lifetime warranty. It also cost less than half what the Motorcraft does. I wouldn't have bought it if I long tripped my '98 but it's day for doing long trips is over.

I'd feel a little bit better about Motorcraft parts at their higher price if they at least offered a lifetime warranty on anything that isn't a wear part like shocks.

My explorer is a response unit so it has to work. I’m currently looking for a quality ford mechanic bc my local dealership are total morons. But I’ve run many many cars over 200k and I always use oem parts. The only exception are upgrades, batteries things of that nature. But if it’s a part going on the engine or trans I don’t gamble.

 

[J_C]

My explorer is a response unit so it has to work. I’m currently looking for a quality ford mechanic bc my local dealership are total morons. But I’ve run many many cars over 200k and I always use oem parts. The only exception are upgrades, batteries things of that nature. But if it’s a part going on the engine or trans I don’t gamble.

That does not justify illogical assumptions about commodities like oil or spark plugs.

Everyone has vehicles that just "has to work". Response unit isn't any different than the owner who needs to get to work or school or just the grocery store so they can eat. Everyone needs their vehicle to work.

On the other hand you did point out the more important variable which is the competence of the mechanic, which is why I almost never let anyone touch my vehicles besides recall work.

Oil in particular is just ridiculous, there is no reason at all to prefer the motorcraft synthetic blend over any major brand synthetic. You want to state that your use is very important, and it might be, but that is not a reason to form an illogical affection to Motorcraft instead of doing the same due diligence as everyone else, because we all value our vehicles being reliable.

I have never had a premature failure due to using non-Motocraft fluids, while parts, there's no way my crystal ball could predict that, I only know that the motorcraft part failed so that is why I was replacing it.

 

[jwolfe]

Their oil is cheap and reliable. The only other oil I would consider is max life high mileage. I’d really love to find a mechanic that will let me supply my own oil and filter and charge me labor. I don’t trust shops with large oil drums of who knows what.

Plugs I can’t tell you how many stories I’ve heard about aftermarket plugs failing in Fords.

And water pumps are an issue on these so it’s crucial to use the correct fluid and change it often (new yellow coolant). I plan to do annual transmission and coolant changes and brake fluid every other year. Gear oil every year. Regardless of mileage.

 

[J_C]

Their oil is cheap and reliable.

Just stop.

You don't want to put any thought into it and that's okay. Motorcraft parts won't do you wrong but you're paying a pretty penny for them instead of investing the time to learn more.

Again, oil is the most ridiculous topic to focus on. It will run fine on any oil spec that meets what is in the owner's manual, and equivalent oil that meets that spec is cheaper if it doesn't have the motocraft markup.

#cantfixstupid

 

[jwolfe]

Just stop.

You don't want to put any thought into it and that's okay. Motorcraft parts won't do you wrong but you're paying a pretty penny for them instead of investing the time to learn more.

Again, oil is the most ridiculous topic to focus on. It will run fine on any oil spec that meets what is in the owner's manual.

I suspect that you don't DIY much.

I work on my cars all the time. I have half the interior out at the moment for electrical work.

But I’m not going to change my oil it’s just a mess and I don’t have time to deal with it. I’d rather pay a competent mechanic to work on things I can’t do or don’t want to do at home.

I’ve never had an OEM part fail due to defects. But I’ve seen countless examples of aftermarket parts failing. It’s like batteries yeah you can get a cheap one but at -10 degrees you’re gonna regret it.

 

[J_C]

I’ve never had an OEM part fail due to defects.

This makes no sense.

if you never had an OEM part fail, then what experience would you have replacing parts? It is a design defect if it fails prematurely.

There are wear items, but again it has nothing to do with OEM replacements.

This is a waste of time. You do you, and pay a premium, and sleep well at night, as I do too.

 

[BrettS.]

Not to get off into a tangent on aftermarket parts but it is so part specific. Some aftermarket parts address a design defect and improve upon the OEM design. Other aftermarket parts meet a price point and quality is decreased to hit that manufacturing price point. Yet still some OEM part suppliers will repackage the same OEM parts for multiple resellers for different branding. You might be paying half the cost for the same product just repackaged for a 3rd party seller. And then there is the lowest quality, cheapest price point which is flooding the resale market, cough Ebay, cough Amazon... This doesn't even get into the fakes, knock-offs, and imitations. Sadly its a buyer beware these days.