Serpentine belt, tighten tensioner pulley

[Steve Peters]

For #reasons I've replaced the alternator in my 1999 Explorer. Not only is it the first Ford I've had since my 1978 Ford Econoline, but it's my first alternator replacement. Yay for me.

I've done enough work on vehicles that I neglected to look up instructions before I started work and didn't realize that one can get the belt off by just using a wrench to loosen the tension on the idler pulley.

As a result, I removed it. Now that everything is re-assembled it's clear from visible inspection that the belt is too loose, and it's very obvious when I go to drive it with the squealing and not running the power steering at low revs.

At the parts store, I gave the replacement alternator a very careful look-over to make sure it seemed identical to the previous, so while not having used a ruler to check, the pulley on the new alternator I believe is the same size as the original.

The idler pulley (the one that holds the tension) is the very same one I took off, which kept the belt at the proper tension before I took it off. I believe I got it on the engine block in the proper keyed position so the spring should take up the tension in the belt, right? The belt is the same. Everything is same except the replacement alt, which was visually the same.

Did I somehow did I overlook something I should have done with the assembly before I put it back on? While typing this, I question about whether I missed something about how it keys into the engine. Was I a notch off or something?

Any input from them intarwubs?

Thanks for your help, Steve

 

[Mr. Alligator]

Recheck your belt routing very carefully.

Good luck.

 

[koda2000]

Your belt routing is incorrect. You don't say which engine you have, but you may have a sticker on your radiator support that shows you the belt routing for your engine. If not you can Google the belt routing for your model and engine.

Example:

 

[Steve Peters]

This morning I went out and checked. The belt routing is correct. I can see how one could get it wrong, but it matches the diagram under the hood. Dang, an easy fix down the tubes, eh?

The amount of deflection in the belt is outrageous, it's clearly too loose. Clearly the tensioner is not keeping it tight enough.

Yet it was fine before I took it off. Mysterious! How did it go wrong when I took it off?

- Steve

 

[swshawaii]

Signs of Belt Tensioner Failure

 

[Steve Peters]

Belt tension was fine before I took the tensioner off. Now it is not.

How could it have possibly gone bad in the meantime? What the heck did I do wrong around here?

 

[fast_dave]

@Steve Peters

My .02 = The Belt Tensioner assembly is not keyed up properly upon re-installation.

OK - so let's assume you properly routed your serpentine belt according to the chart.

If you were able to re-install the belt WITHOUT having to insert either a Breaker Bar OR Long Socket Wrench with a 3/8" end into the Belt Tensioner Assembly, and really work at overcoming the tension of the belt tensioner spring, well - it's installed off key.

Lemme put it to you this way; When installed properly, it should be a SOB to overcome the tension of the belt tensioner spring while re-installing the serpentine belt.

Hope that helps!

 

[koda2000]

It had plenty of tension when you removed the pulley from the tensioner, there's no reason it shouldn't have plenty of tension now. @fast_dave is right, it should be really difficult to push the tensioner to the point where the belt can be put back on the alternator. I usually have to lay under the vehicle with a ratchet on the tensioner pulley bolt and push on the ratchet handle with a piece of pipe while a helper fights to get the belt back on the alternator and it's a battle.

Either the belt routing is wrong or the spring in the tensioner is broken (which I find unlikely). Please recheck your routing, maybe take a picture and post it. You won't be the first person to get it wrong.

 

[Steve Peters]

It had plenty of tension when you removed the pulley from the tensioner, there's no reason it shouldn't have plenty of tension now. @fast_dave is right, it should be really difficult to push the tensioner to the point where the belt can be put back on the alternator. I usually have to lay under the vehicle with a ratchet on the tensioner pulley bolt and push on the ratchet handle with a piece of pipe while a helper fights to get the belt back on the alternator and it's a battle.

Either the belt routing is wrong or the spring in the tensioner is broken (which I find unlikely). Please recheck your routing, maybe take a picture and post it. You won't be the first person to get it wrong.

It's not that hard to tell the belt routing is correct based on the diagram under the hood, but it would sure be hard to take a photo of it.

Based on the feedback from you helpful folks, I do believe I'm looking at a keying issue. I can't imagine the spring inside that thing died from a broken heart when it was out of the vehicle.

 

[Mr. Alligator]

I routed a serpentine belt improperly once.... it looked perfect. But instead of going over a pulley, it went under. Everything else was perfect. And the resulting belt tension was off by a few inches. The reason it would be hard to take a photo is that it is all very tightly spaced and compactly put together in dark spaces.

When I did it, and went back to check, I was sure I had NOT made a mistake. It was all so close. And easy to overlook an error. I even went down to the auto parts store to ***** about belt sizing....

Make sure the every flat side of the belt rides on the flat pulleys, and the grooves of the belt sit on grooved pulleys. At EVERY point of contact the flat back of the belt is on flat pulleys, and the grooved part of the belt is on grooved pulleys.

You might check routing one more time, especially since it costs nothing.... (Sorry if the advice is repetitive, just my thoughts, having made this error myself and having been so sure I had it right.)

Good luck.

 

[Steve Peters]

I routed a serpentine belt improperly once.... it looked perfect. But instead of going over a pulley, it went under. Everything else was perfect. And the resulting belt tension was off by a few inches. The reason it would be hard to take a photo is that it is all very tightly spaced and compactly put together in dark spaces.

When I did it, and went back to check, I was sure I had NOT made a mistake. It was all so close. And easy to overlook an error. I even went down to the auto parts store to ***** about belt sizing....

Make sure the every flat side of the belt rides on the flat pulleys, and the grooves of the belt sit on grooved pulleys. At EVERY point of contact the flat back of the belt is on flat pulleys, and the grooved part of the belt is on grooved pulleys.

You might check routing one more time, especially since it costs nothing.... (Sorry if the advice is repetitive, just my thoughts, having made this error myself and having been so sure I had it right.)

Good luck.

I totally get checking more than once or twice or three times, sometimes the best of us overlook the simplest of things. I have at least a minimum level of competency, but I don't pretend to *really* know what I'm doing. . I figure anytime I take something apart that I haven't worked on before, it's going to be at least a two week process.

UPDATE:

The idea that the tensioner was keyed the wrong way sounded like a strong theory. So I put on my diving suit and got back in. Turns out you can key it the way I had it, or you can key it 180 degrees the other direction. The other direction completely disengages the tensioner from the belt, and even if it didn't it would be pressing the wrong direction. No good.

So I put it all back together the way I had it before and turned it on. Lots of belt squeal, but no "you ain't charging" alternator light on. Huh.

I let 'r run for a few minutes to see if anything changes. Constant belt squeal, no battery light. Turn it off and take a closer look. Over the A/C pulley, the belt was one notch off - that is, overhanging one belt notch towards the engine – no doubt causing the belt squeal but also tightening the belt just enough to drive the alternator properly.

TEST RESULTS:

This is a 20 yr old vehicle, with 200k miles on it, which I bought from a trusted friend but I've only had for about a year. One night, I get in it with my mom (visiting from out of town) and my daughter and it's charging system is working so poorly that we barely make it home. I assume it's the alternator, and I replace it without having it tested. Still a problem. I take the battery in, it's old and it tests bad. I replace it, still a problem. This time it's clear that the belt is loose. I monkey with it some more, and it turns out that taking just a slight amount of slack out of the belt (causes a horrible squeal) but drives the alternator enough to charge the battery.

CONCLUSION:

In a car with this much use and age, multiple problems should be expected. In this case, it's clear that the battery was old and marginal at best. The alternator may have been fine – my fault for assuming it was the culprit. Based on the experimental results from Science Team Alpha, I believe that the spring in the tensioner has simply worn out over these many years/miles, leading to insufficient belt tension and failure to drive the alternator properly.

So, here's the question. Do I:

1) Do I go back to the wrecking yard where I'd already pulled out a tensioner pulley and only took the bolt so it must still be sitting there where I left it. Certainly cheaper, but who knows if it's any better than the one I've got?

2) Give up and throw the 50 clams down on a new assembly.

How long am I holding on to this vehicle? Hard to say. Everything in my life is up in the air. Certainly at least for another year, possibly quite longer.

As usual, thanks for your help.

 

[XLTrunner]

If it were me, I'd make a trip back to the JY and pick up the used tensioner. At my local U Pull, I think they are about $12. There's a good chance the one you pulled will work just fine. I did that very thing and it's been on my Explorer for 3 yrs now. I'd also try to find another Explorer while there with the same engine as yours and either take a pic or make mental note of the position of the tensioner just to confirm that yours is in the correct position.

Unless I missed it, you still haven't revealed which engine you've got.

 

[koda2000]

200k is not a lot of miles for our trucks. Every Explorer/Mountaineer I've owed I bought with around 180K-200K on the clock and the only ones that have died on me were 2 of the SOHC V6's (the 3rd SOHC had the engine rebuilt/replaced by a previous owner). The OHV engines can easily go 300k-400k with maintenance. Of course, as with any old vehicle, you have to stay on top of maintenance and repairs. If you just drive them until something breaks you're not going to have a reliable vehicle. Personally I wouldn't go with a junk yard belt tensioner unless it looked as if it was fairly new, but I understand using JY parts depending on what your budget allows.

Tip #1: For future repairs I suggest you not guess at what needs to be replaced. That just wastes money. Your original alternator was probably good and apparently your battery was the problem. I don't know if replacing your belt (and now the tensioner) was necessary, perhaps the belt was worn out and perhaps the tensioner was also worn, or perhaps you damaged the tension in your unorthodox method of removing the belt. So you wasted your money on an alternator. If you purchased a reman alternator I hope you got one with a lifetime warranty,as many reman electrical parts are junk today.

Tip #2: While your belt is off, I recommend you spin your various pulleys by hand. if they make noise, feel dry and spin too easily you should replace them. Waiting until a pulley fails can cost you way more the the price of a pulley.

 

[donalds]

I had this same problems took a bit to figure it out I fixed it with a different belt a few mm shorter most likely the tensioner is fine
I 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

My 2¢

 

[Steve Peters]

The story so far: One night Our Hero got in his 1999 Explorer with his Mom (visiting from out of town) and his young daughter (on loan from the Ex) to make a short trip and discovered the alternator light flickering, and solid on at idle. Did the trip, limped home before it died. (see previous posts for details)

About a year ago, right after I bought it from a trusted friend, the negative battery cable developed issues, and for a while and I didn't figure it out right away. At one point I discovered that the only ground was that little secondary wire to the battery... ah, no wonder the radio hasn't been working right, eh?

So I had reason to suspect the charging / ignition system had been abused by mistake.

I decide to replace the alternator. I was so sure this was the problem I didn't bother to have it checked #mistake. Probably it was fine. That installed, we still have a charging problem – I find that the battery can't be charged from my 120v battery charger. Get that tested, it's bad. Replace. However, Houston, we still have a charging problem.

I'm fooling with the tensioner pulley, and during one of my tests the engine reports fine for a change. Huh. I take a closer look and discover the belt is just slightly off one of the pulleys and is thus just slightly tighter. When I place it back in it's proper track, the charging problem reappears.

Bingo. The tensioner pulley isn't keeping the belt tight enough to keep everything spinning properly.

Sure enough, I put in a used tensioner out of a wreck and like magic, now it all works.

Genius! In retrospect, the tensioner was probably the source problem, not spinning the alternator fast enough to make up for the weak battery, which due to it's age, probably would have been replaced shortly anyway. I'm guessing that replacing the alternator wasn't necessary, but as I'd already turned in the core ... well, now I've got a new alternator.

While we're learning things the hard way, here's a bit more of the journey: When I was at the U-Pull the first time, I was just in search of the bolt that holds the tensioner in, as I'd dropped it and it completely vanished. (Our Hero failed to look up hints for what he was doing and thought he had to take it off, instead of backing off the tension). I get the bolt, leave the tensioner under the hood and go home. Stuff happens re: previous posts, I realize that my tensioner has gone bad, I get on my scooter and do the hour and a half round trip on the scooter in the rain to fetch the tensioner I'd left behind ($30). It doesn't seem to fit on the car. Curse words! I go a few blocks away and fetch a brand new one, that one also doesn't fit, won't key into the engine block. Curse words! I return that one, go to NAPA and buy the $60 one that really does seem identical to the original.

I go back home. Then comparing the original one, the new one and the junkyard one... I realize that the JY one was FINE and I'd been just too tired and annoyed to notice that I was trying to install it backwards. Put it on the right direction and all is well. Four pointless trips to the auto parts store. Let's hope this is lesson learned.

Well everyone, thanks for your help. Hopefully this story will assist the next sad sack

 

[imsick247]

Glad you got it figured out!
Not covered here, but I went through the opposite. I'm posting just to cover another possibility...the belt was too short.
I damaged the tensioner by pulling it too tight while trying to get the belt on.
Eventually, I took the belt back to the parts store and we measured the belt for vehicles with AC vs the belt for vehicles WO AC.
The store had the part numbers reversed in their database.

 

[donalds]

Yeeyeee good times

 

[Steve Peters]

Glad you got it figured out!
Not covered here, but I went through the opposite. ImI'posting just to cover another possibility.
The belt was too short.
I damaged the tensioner by pulling it too tight trying to get the belt on.
Eventually, I took the belt back to the parts store and we measured the belt for vehicles with AC vs the belt for vehicles WO AC.
The store had the part numbers reversed in their database.

Aha! Now I know why all the parts shops I spoke two asked if my engine had A/C or not. Different length belt, and perhaps different tensioner.

 

[XLTrunner]

Congrats...you stuck with it and overcame! And, you learned something along the way. That's how most of us got started. I'm fortunate in that I have a U Pull about 15 minutes from my house. It's been a great hands-on learning center in addition to being a source for nice used parts cheap.

 

[helodrvr1]

Steve, thank you for posting that. Most of my repairs go the same way, as I am no mechanic but consider myself mechanically-inclined (dangerous combo). I always try to compare a replacement part (new or used) to the part I'm pulling out, but sometimes lose it (like you did) or misalign it or outright break it. And it REALLY stinks when the "experts" at the autoparts stores give you the wrong info (part numbers, in imsick's case); makes me feel like the whole world's against me. It's great to have a forum like this to "tell our tales" and, as XLTrunner said, we learned something along the way.