cummins isx belt tensioner.

Yep, the tensioner will have a 1/2" square drive in it so you can pull it (or push it) to loosen it with a 1/2" drive ratchet. You got real good life out of that belt!!! Replacement of the tensioner depends. They are spring loaded. When you move it to remove the belt and it does not spring back, time for replacement. Once your belt is off, spin the roller by hand. If it doesn't not spin smoothly, or you can hear funny noises, the bearing is worn and time for replacement. If you want to do some preventative maintenance, now would be a good time to replace it anyway.

 

I don't know what year you have, but my Cummins has a 3/4" square drive on the right side main belt and a 1/2" square drive on the left side A/C belt. It is not normal for a belt to last 600K - are you the original owner? If not, it most certainly has been replaced before by a prior owner, if you are, and the belt really made it that long, that's pretty much the longest lived belt I've ever heard of in my life. Tensioners can have several problems. As mentioned before, the bearings can go up in them which causes noise and a wobble. The tension spring can also wear out, which causes loss of tension on the belt and allows it to slip over the side of the pullies and get torn up by the pullies themselves. They recommend a tension gauge to check this, but myself and everyone else I know does a pull and twist on the belt to make sure it is not turning more than about 90 deg. It is not a bad idea to replace it at 600K if it is original because it's probably at the end of it's life and you have to install the new belt to really check it anyway (and when it fails, it will likely take your belt with it). The other things that can cause belt failure are bearing failure in other pullies including idler pullies, alternator, A/C, PS, anything that is belt driven on the system. Again look for noise and wobble to determine this. If you want to diagnose before you do anything else, get your new belt and install it and inspect the other pullies from there.

 

Wow, that's incredible for sure if that's original belt. My '06 I was replacing pretty much once a year, it would start squealing and chirping when it was time.

 

I think Id replace it anyway. Then youll know its new. I had a belt do that. the first Volvo shop said the tensioner was ok but I got about a 1000 miles down the road and it shredded that new belt. The people at the second Volvo shop said the first should have replaced the tensioner because that's the only thing that shreds a belt like that. They replaced it and I didn't have anymore problems with belts.

 

get the cummins # and cross it to gates, dayco, or goodyear and save a 100 buck while your at it

 

I think I'd replace the tensioner and pulley as preventative maintenance and check the alternator, fan, and AC clutch bearings while you have the belt off. I've seen several trucks crank slow and refuse to start because of seized AC clutch bearings. Cheaper to check it while you're in there, and repair as necessary.

 

I have a 04 CM870 ISX in a 2004 International 9400i.
When I replaced the tensioner last year I used the new bolt that came with the new tensioner. LARGE MISTAKE!!!
It was shorter then the original and didn't torque down correctly and tried to strip.
Apparently, they use this tensioner in other applications where a shorter bolt can be used, NOT the ISX
All in all not a hard job to do with basic tools.
Best of luck

 

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Has anyone had trouble with the threads stripping out of the bracket that holds the air conditioner tensioner? If so what is the fix?