Harmonic Balancer replacement

[schardein]

About a month ago, I started noticing a "tinging" sound from the engine upon startup.  It didn't go away, and increased with engine speed.  It sounded like something was hitting the mechanical fan.  I looked with the engine running, but couldn't see anything.  It still ran fine, so I drove it.

 

About two weeks ago my radiator sprung a leak.  I put some stop leak in it to stop a small leak back when I bought it in 2013, so I wasn't really surprised, and figured it was time to just go ahead and replace the radiator.  That project is still underway, because I found the source of the noise.

 

The rubber inside the harmonic balancer has started bulging out, just enough to contact the tip of the mechanical fan.  I'm an experienced mechanic, but I can't recall ever changing a harmonic balancer on a Jeep 4.0.  Does anyone have any pointers from previous experience?  Rockauto prices range from $27-$51, or would I be better off with a oem used one ($21 w/ $2 core)?

EDIT:  This is on my 91 XJ.

[eaglescout526]

I know this:

 

So if you go OEM this will be your issue. Try to go with the original part number 33002920 in the aftermarket if you don't want to replace the slinger.

 

I've done mine on my 2.5L a couple times. You will need a balancer remover and installer. They say to remove the radiator for more clearance on the puller and installer which is probably more true for the 4.0L than the 2.5L. Basically you will need as much clearance as possible to remove and install a new one.

[Minuit]

I would not buy a used one as this is an age-related thing. The rubber decays over time and this is the result.

 

They aren't bad at all to replace. You can do it without removing anything else. For what it's worth, I put a Dorman balancer on my 91 several years ago and it's doing just fine still. The puller tool you rent from the parts store will do just fine to get it off. I would strongly recommend either buying or renting the harmonic balancer installation tool as well - I do not ever suggest using the crank bolt to pull one on, even if it may work 95% of the time. I left the oil slinger in place, and there was no problems. The crank bolt is torqued to 80 ft-lb with lubricant.

[schardein]

7 minutes ago, eaglescout526 said:

I know this:

 

So if you go OEM this will be your issue. Try to go with the original part number 33002920 in the aftermarket if you don't want to replace the slinger.

 

I've done mine on my 2.5L a couple times. You will need a balancer remover and installer. They say to remove the radiator for more clearance on the puller and installer which is probably more true for the 4.0L than the 2.5L. Basically you will need as much clearance as possible to remove and install a new one.

Good info.  I can't picture the slinger.  I assume the belt failure would be due to the damper being out of plane (alignment) with the rest of the belt system?

5 minutes ago, Minuit said:

I would not buy a used one as this is an age-related thing. The rubber decays over time and this is the result.

 

They aren't bad at all to replace. You can do it without removing anything else. For what it's worth, I put a Dorman balancer on my 91 several years ago and it's doing just fine still. The puller tool you rent from the parts store will do just fine to get it off. I would strongly recommend either buying or renting the harmonic balancer installation tool as well - I do not ever suggest using the crank bolt to pull one on, even if it may work 95% of the time. I left the oil slinger in place, and there was no problems.

Yes on the age related failure, but a late WJ would still be 13 years newer than my 91 XJ (but still 16 years old haha).  But yeah, at this price level, new is the only thing that makes sense.

I think I have a crank pulley puller, if not I will buy one and add it to the collection.

 

As it turns out, the radiator is already out, so there's some good news.

[eaglescout526]

2 minutes ago, schardein said:

Good info.  I can't picture the slinger.  I assume the belt failure would be due to the damper being out of plane (alignment) with the rest of the belt system?

Yes the age of damper and the rubber separating would be the cause. I believe the stout on the damper is longer which requires the slinger to go away.

[Jeep Driver]

The oil Slinger is internal and irrelevant.

Dayco makes a good balancer it is sold through oreillys right around fifty bucks if I remember correctly.

[SVPete]

A harmonic balancer puller and installer can be borrowed from autozone under their loan-a-tool program. You do not have to remove the radiator or anything else but the belt on a 4.0.....other than a skid plate, if installed.

 

If the bumper is removed, it is easier, but not necessary to accomplish the task.

 

The right tools make it a 1 hour job tops, not including the front seal, which I highly recommend you replace since you have the balancer off. Did this twice in the past year on my Cherokee (since I didn't replace that seal....)

[schardein]

Just now, SVPete said:

A harmonic balancer puller and installer can be borrowed from autozone under their loan-a-tool program. You do not have to remove the radiator or anything else but the belt on a 4.0.....other than a skid plate, if installed.

 

If the bumper is removed, it is easier, but not necessary to accomplish the task.

 

The right tools make it a 1 hour job tops, not including the front seal, which I highly recommend you replace since you have the balancer off. Did this twice in the past year on my Cherokee (since I didn't replace that seal....)

I was writing this as you posted:

 

My XJ is an auto.  Even with the radiator out, I didn't have room to get my Dewalt cordless impact in to break loose the harmonic balancer bolt.  I found it much easier to go ahead and remove the front bumper.  Had a puller on hand to get the balancer off.  Now to source parts, I did plan on doing the seal at the same time.

 

On a separate note, I don't know what the spec is for crankshaft thrust bearing clearance on a 4.0, but after removing the bolt I grabbed the balancer with my hands and gave it a good tug.  I was surprised when it moved noticeably.  I thought maybe it was loose on the crank, but turns out the whole crank is moving in and out.  Quite a bit, haha, like an 1/8 of an inch.  The engine has 238,516 miles, and runs great.

[SVPete]

My 1992 XJ is automatic too.

 

I used a screwdriver and 18" breaker bar to break it loose both times.

 

First time the bumper was off for other reasons. Second time, earlier this month, I didn't remove anything but the skid plate I recently installed.

 

A powered tool certainly will make removing the bolt easier, but I don't have one.

 

Balancer on my MJ and XJ are both the Dorman brand from RockAuto. MJ was done a couple of years ago (215,000 miles), XJ needed it replaced when I bought it (165,000 miles).

 

I think the seal I used was Duralast from AutoZone.

[schardein]

19 minutes ago, SVPete said:

Balancer on my MJ and XJ are both the Dorman brand from RockAuto. MJ was done a couple of years ago (215,000 miles), XJ needed it replaced when I bought it (165,000 miles).

Rockauto isn't showing the Dorman brand for a harmonic balancer.  Went with the Dayco that Jeep Driver mentioned.  Also added this installer to the order:

https://www.rockauto.com/en/moreinfo.php?pk=8760876&jsn=357

[75sv1]

If your crank is moving 1/8, then it probably wore the thrust bearing. I had this happen a year or so ago. I had to get another crank. Fortunately, my neighbor had a good used crank. Even used the bearing out of that engine. Only suppose to be a few thousands movement. I used a High performance harmonic balancer ($100). Still, no real reason to spend  that kind of money.

[schardein]

10 hours ago, 75sv1 said:

If your crank is moving 1/8, then it probably wore the thrust bearing. I had this happen a year or so ago. I had to get another crank. Fortunately, my neighbor had a good used crank. Even used the bearing out of that engine. Only suppose to be a few thousands movement. I used a High performance harmonic balancer ($100). Still, no real reason to spend  that kind of money.

So the crank was worn, and not the bearing?  Is that a common 4.0 thing?

[75sv1]

12 hours ago, schardein said:

So the crank was worn, and not the bearing?  Is that a common 4.0 thing?

No, both were worn. I had to replace both the bearing and the crank. The block I scrounged the crank from, the bearings looked almost new. So, I used them. I did replace the rod bearing with new ones. I think that block  is the one I am using for a stroker motor. Long story on that. Anyways, I do recommend replacing harmonic balancers as a maintenance item before this happens. I have an 2000 XJ, that I will replace the harmonic balancer soon. 260K on it.