Serpentine Belt Tensioner

Hey everyone!

Did some reading and researching but I'm just looking for a sanity check real quick before I pull the trigger on parts... I've noticed when I accelerate quickly, I hear what sounds like my serpentine belt slipping... However, I don't smell burning rubber which I've read is pretty evident when your serpentine belt slips. I've replaced all idler pulleys and the belt within the past 5k miles during a diagnosis of the PS pump that was going out but I'm pretty doggone sure it's the tensioner causing some belt slip now.

Also, if anyone knows a link to a video or writeup on replacing the tensioner that would be awesome since it looks like a real PITA!!

(For reference I have the 4.0)

Thanks.

 

Just replace the bearing, not the whole bracket

 

+1 change only the pulley. Stow the tensioner for a rainy day.

The pulley is left hand thread, so be aware of that.

 

If the belt truly is slipping due to poor tension then replacing the just the pulley isn't going to do anything unless the pulley is super glazed. Grab the belt and try to twist it. If you can go more than 90 degrees it is weak on tension. Mine had good tension but was making a clicking noise. I just did mine not long ago. Although I am a mechanic with access to an arsenal of tools I didn't find it too hard. Remove battery, Alternator. Loosen AC compressor and move up and down depending on which of the 5 bolts of the tensioner bracket you are going after. I found no need to remove the fan or shroud. I worked a lot under the hood and through the wheel well I got the rest. Took me two hours in total.

 

It's not the pulley that maintains the spring tension so need to do the whole assembly. My 09 was doing the same thing on hard accel the belt would slip and I could smell it some time.
You have to pull the alternator and then the AC pump bolts that are on top of the tensioner bracket and slide the AC pump over some (do not disconnect any refrig lines) so you can reach the tensioner. Have to go thru the wheel well so jack it up and pull that drivers side wheel off and you will need several extensions and shivels. After a few or several choice words and repositionings of the socket and extension you will get the bolts off.
Search TW for how to do posts.

 

Thanks for the input! Not quite sure what changing the pulley would do since I’m basically 100% sure the belt is slipping and just wanted a sanity check. I’m going to order the part soon and most likely also replace the alternator with it since it’s starting to whine. Plus my truck is about to roll 200K so I don’t think it would be bad preventive maintenance as well!!

 

I just re and red my tensioner only took me 3 hours
Disiconnect battery
Remove battery and tray
Remove mud guard or skid plate if you have one
Remove belt
Remove alternator
Remove electrical on ac compressor
Remove 4 bolts that hold compressor on
Push compressor out of the way
Remove 5 bolts that hold tensioner on
Reverse steps
I worked fromm the top, through the wheel well and from underneath

 

If the idler pulleys have never been replaced, do those at the same time. They will only add a few minutes to the length of the job. The OEM ones aren’t cheap for what they are but it’s not something you’ll likely ever need to do again. You could also just replace their bearings, there is a good thread with part numbers if you choose to go that route. I went with OEM when I did mine, no regrets. My tensioner thankfully still provides good belt tension.

 

I mentioned I had already done that within the past 5k

 

People will recommend that you change the pulley first because it is far easier than replacing the tensioner and just like any of the other pulleys they can make noise. Thats what I did when I diagnosed mine the first time. I put my stethoscope on the bolt of the pulley and I heard clicking so I replaced the bearing. When that didn't fix it I listened again but this time got on the bracket of the tensioner and still heard it only there and the rest is history. Not a bad idea on the alternator either. They come out of the top but be warned it is a little tricky to get it out. disconnect brackets and harness retainers around the area to make room to remove easier.

 

Yeah... guess whose alternator froze up without warning a couple of months after the belt and pulley replacement? I briefly thought about doing it then went "Nah, who does that? You're overthinking it."

 

Haven’t noticed anything too bad other than a whine when it’s cold… It still puts out up to about 14.4 volts but usually sits around 13.5-7v. Figured since you pretty much have to remove it, I’d go ahead and just R square it.

What alternator did you end up going with?

 

I got a reman Denso. It was what I had seen as the most recommended one and that’s what lasted ten years and 112K miles so I can’t really complain.

I had checked its spin when scoping out the pulleys and it seemed fine. Drove it to Death Valley and back again just before it froze up; damned glad it didn’t do that while I was parked way the hell up a dry wash.