I would say yes but that one is smooth and mine has grooves on it so I don't think the belts are routed the same way on the 4.0 vs the 4.2

 

These are the bearings I used on my 4.0 which has one YJ and one XJ idler:
http://www.amazon.com/dp/B00ZSQT0WA...p/B00ZSQT0WA/ref=cm_sw_r_cp_api_glt_i_YRQDWDGFRYMNA91R40GD?_encoding=UTF8&psc=1
They are inadequately factory greased- use dental picks and very carefully pop the rubber seals off and use gold/amber NLGI2 bearing grease and pack them. Replace the seals.
I've got ~40K miles on mine.

Or you can buy Dorman assemblies with pulleys for US$20- $40

I don't think it matters if the idlers are grooved or not- no driven force on them.

 

Is one of them the grooved 4" pulley? I don't know if they used the same bearings on all their pulleys

 

Pretty sure the bearings aren’t different

 

Autozone has them for 13.99. The bearing comes in it.

 

^^^^ that might be the ticket?

As far as bearings. I can go into a Napa parts stores here snd give them ID and OD and they can cross reference and find stuff. Bearings like these are most often, like almost always, parts bin pieces and all you need to do is match or cross reference the part #

If there's one nearby you https://bearingspecialties.com/rings.html you might find they have a sealed bearing or shouldered bushing that could work

or for that matter @bruinjeeper needs a retaining ring...

 

Well I got the bearing that's for the YJ and XJ idlers and....it's not the right size

the dimensions are right but the inside diameter is too big, it's 17mm when mine is 12mm

 

There is a top-hot-shaped shouldered sleeve that the bolt goes through. So the bearing ID is bigger than the bolt generally. The bolt fits the ID of the sleeve.
https://www.moparpartsinc.com/p/Jee...s-built-up-to-06-01-89--Heater-only/42372728/53002905.html?partner=BingShopping

 

Mine didn’t have that when I took it apart, it was just a bearing

I don’t know where I could buy just the sleeve thing so I can use the new bearing, is there a part number for that?

Part number on the bearing is F/\G(keeps trying to censor it) 559000 CANADA

according to CJ people this is a common bearing to not be able to find

 

The 13.99 one is for the 4.0 which has the smooth idler pulley. The smooth pulley doesn't work on the 4.2 because it can allow the belt to come off since it doesn't have a lip on the edges

I ended up ordering the top hat piece from the auto parts store. It was like $4 and fits perfectly in the larger bearing that was supposed to be for my engine. I don't think the ID is right though so I'll need to drill it out to fit the bolt, but not a big deal

 

Glad you got it

For future reference the smooth pulley as an idler will NOT let the belt come off. Especially if the pulley before and after it have the grooves is not going to come off.

The grooves aren't to hold the belt on btw. The grooves are to give the belt more surface area of contact so at a belt tightness that won't kill the idler bearings or water pump it won't slip, either. Because instead of using three belts the serpentine belt takes all those loads onto itself. FYI

My water pump and two idler pulleys are smooth iirc (4.0) and the belt has never come off.

 

Yeah the hole was too small so I had to drill it out but it's all together now