Serpentine Belt Sizing

[jlrohio]

So, I changed things up again this morning while doing some more research into the the differences in the length.
One strange thing I came across, that I did not think about, was that there is a belt for Explorers withOUT A/C. I've never heard of not having an A/C in one of these...but I guess it could be a thing...or someone removed the A/C from their vehicle.

Anyway, back at my research, I came across Advance Auto selling a Dayco Serpentine Belt Kit (Serpentine Belt, Pulley and Tensioner) for $35.60 + shipping. Factor in a Labor Day discount code for 20% off and some Gift cards I had lying around and this was a no-brainer. Everything else is going back to Amazon and I'll just go with this Dayco setup for now.. I verified the length of the belt (88.25") and should fit. Heck, just the Belt itself at Advance Auto costs $43. Thanks to @J_C for letting me know the size was in the part #.

In the end...I guess this initial screwup in the sizes was a learning experience that I hope others may find useful in the future and I was able to save a few bucks in process over buying all of these parts separately.

View attachment 445234

Well, so much for my Dayco Kit...
Today, my kid calls and tells me that when he puts the vehicle in reverse, there's a clicking coming from under the hood. He says in drive it's fine and he's going to bring the car home and park it,

So, later, I have him start it up and look under the hood. Everything appears fine with the belt, idler pulley, etc. I tell him to put it in reverse, thinking there may be some sort of transmission issue and there's a clickty-click that comes from the passenger side of the motor up front!
He puts it in park and it goes away. So, I get around to that side of the car and tell him to put it in reverse again and as he does, I see the Belt Tensioner jumping all around (which I've never seen before) and then as soon as the car gets to reverse, it starts clickty-clacking again...like some sort of morse code or old teletypewriter...and I can see the Belt Tensioner slamming into itself! Ugh!! I also noticed that putting the A/C on can also trigger it.

Guess I'll be on the phone with Advance Auto and/or Dayco tomorrow.

Here's some video's for your enjoyment (Don't have the sound up too much, you'll probably wake up a dog or cat wondering WTF that noise it!)

 

[98Collector]

I appreciate you helping solve my belt length mystery. One thing I’ve found makes it easier is this time I used one of those belt grabber tools, it was about $15 on Amazon. And everyone with the 4.0 probably knows this but I didn’t the first time, Is that when routing the belt, put it over the top smooth idler pulley last, because it’ll just slip right over the edge. When I changed one the first time I tried putting it over one of the other ones last and it wouldn’t go over the sharp edge. Also I’ve noticed the belt never seems to wrap around the water pump quite flush, it always seems to gravitate toward the fan. As long it’s on there don’t worry about whether it’s centered, it should correct itself when you drive it. I do have a serpentine belt tool but didn’t need it for the explorer, I just used a cheap 3/8 ratchet. In my old expedition I went through a lot with the serpentine belt, it broke while I was driving due to seized ac compressor, another time the top idler pulley fell off while I was driving. It turned out it was because the bolt that the pulley goes on was partially broken. With the expedition also, I used a serpentine belt tool but actually needed someone to hold the tensioner down all the way for me while I put the belt on and off. With the explorer it’s been pretty easy to do it myself.

 

[98Collector]

I appreciate you helping solve my belt length mystery. One thing I’ve found makes it easier is this time I used one of those belt grabber tools, it was about $15 on Amazon. And everyone with the 4.0 probably knows this but I didn’t the first time, Is that when routing the belt, put it over the top smooth idler pulley last, because it’ll just slip right over the edge. When I changed one the first time I tried putting it over one of the other ones last and it wouldn’t go over the sharp edge. Also I’ve noticed the belt never seems to wrap around the water pump quite flush, it always seems to gravitate toward the fan. As long it’s on there don’t worry about whether it’s centered, it should correct itself when you drive it. I do have a serpentine belt tool but didn’t need it for the explorer, I just used a cheap 3/8 ratchet. In my old expedition I went through a lot with the serpentine belt, it broke while I was driving due to seized ac compressor, another time the top idler pulley fell off while I was driving. It turned out it was because the bolt that the pulley goes on was partially broken. With the expedition also, I used a serpentine belt tool but actually needed someone to hold the tensioner down all the way for me while I put the belt on and off. With the explorer it’s been pretty easy to do it myself.

88.3 inch Belt went on no problem.

 

[joney]

88.3 inch Belt went on no problem.

View attachment 445556

FWIW, the Motorcraft belt I used (went on fine only after using the belt tensioner tool with its extension) is the one for air conditioned Explorers (98 XLT) The Motorcraft part number is XL2Z8620DA

 

[239]

I had the power steering pump changed on my 2000 OHV a few years ago and have had to try different size belts since then. I don’t know what the stock size is for all the pulleys but belts have been too long or too short causing my tensioners to fail. It doesn’t help that aftermarket alternators have different size pulleys too depending on the brand.

 

[J_C]

^ You can use a puller to swap pulleys if necessary, but if you get a belt where the part # includes the length, then can just deduce what different part # of belt you need, for the difference in length needed. For example my '98's 4.0L SOHC Dayco belt was part # 5060868 and 86.8 inches is the length. You can see the other belt sizes they offer in the 5060 prefix (or whatever your belt prefix should be for the 4.0L OHV) with their PDF:

https://www.daycoaftermarket.com/wp-content/downloads/AUTO_&_HD_BELTS_-_2019_GUIDE.pdf

 

[98Collector]

I had the power steering pump changed on my 2000 OHV a few years ago and have had to try different size belts since then. I don’t know what the stock size is for all the pulleys but belts have been too long or too short causing my tensioners to fail. It doesn’t help that aftermarket alternators have different size pulleys too depending on the brand.

Interesting. I don’t know what I’d do about that except maybe the easiest thing would be to try a bigger or smaller idler pulley and see if that makes the difference. I maybe remember seeing a belt somewhere for the ohv that was a slightly different length but honestly can’t remember.

 

[J_C]

Take a look at that Dayco PDF I linked. Around size 5060883 (88.3", 6 rib belt), there are many sizes slightly longer or shorter in 1/4" to 1/2" increments. No need to buy a new pulley if you wanted to use a different belt instead of swapping over the old pulleys from power steering or alternator.

Different alternator pulley though, look at what the two pulley sizes are, because a smaller pulley is going to increase alternator output at lower engine RPM, but wear out the alternator faster too.

 

[239]

Update: I bought the Dayco kit and it seemed like the idler pulley was too big at first but I put it all together and the tensioner looks ok. The tensioner seems to have an indicator and mine looks like this:

 

[joney]

Thanks for the input! By any chance, can a water pump rattle when it gets worn? I'm beginning to wonder about what the mechanic told me last year, was the source of the rattle (sounds rather like a loose heat shield does, but under the hood.)

Update: So it turns out, the fan does rattle - The local handyman/mechanic found that the fan clutch is bad, causing the fan to wobble, and also making the plastic fan crack! He's a great diagnostician, and finally has time to work on my Ex! Also found out my tires have cracking between the treads, he says they won't last the winter. The oldest one is from 2018 so I knew they're aging out. Still lots of tread on them, never thought to examine that! So ordering some 235/15/75 Goodyear tires soon! ANd he's coming back tomorrow to replace those parts and check my brakes. ANd the water pump shaft is fine, I was mistaken. So nice to have such a gem of a mechanic to work on it for me!

 

[swshawaii]

Update: I bought the Dayco kit and it seemed like the idler pulley was too big at first but I put it all together and the tensioner looks ok. The tensioner seems to have an indicator and mine looks like this:

Good post above. IIRC, the OEM tensioner is made by Gates that use a different spring and indicator than the Dayco shown above. Below is a Gates 38137 used on my 2005 4.0L Sport Trac.

 

[joney]

Update: So it turns out, the fan does rattle - The local handyman/mechanic found that the fan clutch is bad, causing the fan to wobble, and also making the plastic fan crack! He's a great diagnostician, and finally has time to work on my Ex! Also found out my tires have cracking between the treads, he says they won't last the winter. The oldest one is from 2018 so I knew they're aging out. Still lots of tread on them, never thought to examine that! So ordering some 235/15/75 Goodyear tires soon! ANd he's coming back tomorrow to replace those parts and check my brakes. ANd the water pump shaft is fine, I was mistaken. So nice to have such a gem of a mechanic to work on it for me!

Update #2: The rattle is gone! But the squeal from the belt is worse, the mechanic is going to replace some of last year's new parts like the belt and tensioner. The fan had long cracks between each blade!
And I just ordered these from Walmart Black Friday sale: $ 75 each ($30 off) it's what I have now but of course newer. Going to make sure they aren't old either!

Goodyear Wrangler Radial 235/75R15 105S All-Season​