Stranded for an unusual reason (crank pulley / harmonic balancer came apart)

98TxTJ

98TxTJ

TJ Enthusiast
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Joined
Aug 25, 2018
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Near Denton, TX
My crank pulley/harmonic balancer came completely apart, disintegrating at the rubber interface.

I had almost no warning. Started it up and within a quarter mile a bunch of metallic clattering and squealing, then I lost power steering and the alternator. Pulled into a parking lot and the outer ring of the crank pully fell out on the ground.

Amazingly, no damage to fan, radiator, or serpentine belt.

I don't think I've read about this before as a point of failure.
 
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It wasn't uncommon on SB Chevy powerplants back in the day. Can't say I've heard of this on our Jeep 4.0 and 2.5 engines.
 
happend to me once. Originally i was chasing what i tought was a belt squeek. Used some belt dressing and apparently that "helped" in the pulley comming apart faster. Replace it using the same belt and the squeek was gone. If you have the tools it can be repair roadside
 
Funny, I had something similar happen to me. I was chasing a squeaking belt, I thought. I was running late headed to work and was almost there when the power steering went out and the check gauges light came on and temp increased. Pulled over and found the belt was shredded. The idler pulley froze up and ended up taking out the belt.
 
This is a known issue on Chevy LS engines (and maybe others), but this is the first time I've heard of it on a TJ!
 
Chris said:
This is a known issue on Chevy LS engines (and maybe others), but this is the first time I've heard of it on a TJ!
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I'm sure that 210,000 miles factored in, and possibly the Great A/C Compressor Lockup of July 2019.

Pretty soon though, there won't be anymore 200k+ mile parts left on this thing.

Here's someone else's picture of the failure. In my case, the outer ring came completely off and fell to the ground.
failed_harmonic_balancer.jpg
 
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98TxTJ said:
I'm sure that 210,000 miles factored in, and possibly the Great A/C Compressor Lockup of July 2019.

Pretty soon though, there won't be anymore 200k+ mile parts left on this thing.
Click to expand...

The good thing is how cheap you can get even a fully refurbished 4.0 for. Certainly a lot cheaper than the LS7 in my C6 Z06 :ROFLMAO:
 
Chris said:
The good thing is how cheap you can get even a fully refurbished 4.0 for. Certainly a lot cheaper than the LS7 in my C6 Z06 :ROFLMAO:
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A week after we got it we installed a new long block 4.0. It either cracked head or blew a head gasket as soon as I fixed a radiator hose leak.. It didn't matter which based on the miles on the engine. There was no point going to the time and expense of doing the top end without doing the bottom as well and a reman long block seemed the best way to go.

But all the original "external" engine parts went back on. Starter, alternator, PS pump, A/C compressor, crank pulley, etc. So since then, we've been working our way through those.
 
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Had the same thing happen to my old Cherokee 4.0L. I froze my ass off repairing it in late January in an uncovered parking lot, but it wasn't a difficult fix.
 
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A buddy of mine had it happen on his 4.0 XJ. I think it's like a '91 model. I had the pieces that he gave me in a load of scrap metal that I got for various projects around the place (Farm Fabrication material).
 
Just logging in to search and see if this is a common thing on the 4.0L — apparently it is not. But tonight I had the exact same thing happen — lost power steering, and 15 seconds later heard horrible metallic clanging. Pulley completely separated from the isolator ring.

Am I going to have to pull the radiator to get a puller on it?
 
acct21 said:
Just logging in to search and see if this is a common thing on the 4.0L — apparently it is not. But tonight I had the exact same thing happen — lost power steering, and 15 seconds later heard horrible metallic clanging. Pulley completely separated from the isolator ring.

Am I going to have to pull the radiator to get a puller on it?
Click to expand...

On my XJ I did not have to remove the radiator, I used a cheap puller from Harbor Freight if I remember correctly.
 
Standard $20 Chinese 2/3 hole balancer puller from Autozone.

came off and went on perfectly fine — just no room in there with the radiator and shroud. I couldn’t even get a socket on the puller because of the A/C condenser — had to use a wrench from below.
 
Same thing just happened to me. 2.5 liter had horrible noise so I shut it down. I pulled it home and went to start it when the ring fell out onto the ground. I reckon its time to pull the radiator.
 
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