91Pioneer Posted April 2, 2016 Share Posted April 2, 2016 I occasionally get a really loud squealing from the engine. I checked the harmonic balancer and it's good, it's not rubbing. The noise sounds like it's coming from the top of the engine and I can't tell but I'm pretty sure it's either the idler pulley or the AC bypass pulley. If it's not too expensive I'll just replace both pulleys. Problem is I'm having a hard time figuring out what is what on RockAuto. There are a number of options "w/AC", "grooved", "smooth", "accessory drive idler assembly", etc. And there are 14 total pulleys listed under the category Idler Pulley. So help me out here guys, for a 1992 4.0 w/o AC which are the part numbers I need to order? Even if I could figure out the OEM numbers I could cross reference them. I understand the Renix AC bypass is different from searching plus I don't want to buy the whole bracket, just the pulley... also, would the idler pulley be the same with or without AC? I don't have my 91 MJ to compare (loaned it to a family member). Link to comment Share on other sites More sharing options...
91Pioneer Posted April 2, 2016 Author Share Posted April 2, 2016 OK well I was able to find some Dorman part #s. 419-602 is the idler pulley if you have AC, no # if you don't have AC. Crap. They list a part # 34171 but it's the whole AC bypass bracket and pulley. I'd prefer to save some cash and just buy the pulley.... Link to comment Share on other sites More sharing options...
onlyinajeep726 Posted April 2, 2016 Share Posted April 2, 2016 I'm almost 95% sure this one is the correct one... You have re-use the reducer sleeve that sits inside of the bearing. http://www.rockauto.com/en/moreinfo.php?pk=3672&cc=1180314&jsn=385&jsn=385&jsn=385 Edit: I went outside and looked at mine. The pulley I linked is only slightly smaller in terms of its outer diameter compared to the factory one, but the I.D. of the bearing looks to be correct. Link to comment Share on other sites More sharing options...
91Pioneer Posted April 2, 2016 Author Share Posted April 2, 2016 Hmmmm that one is not listed as fitting a 92 Comanche 4.0 on RA. Doh, I'll have to dig more on manufacturer sites I guess. Worst case I'll have to pull mine off and take some measurements and order it that way... Link to comment Share on other sites More sharing options...
onlyinajeep726 Posted April 2, 2016 Share Posted April 2, 2016 Hmmmm that one is not listed as fitting a 92 Comanche 4.0 on RA. Doh, I'll have to dig more on manufacturer sites I guess. Worst case I'll have to pull mine off and take some measurements and order it that way... Shouldn't matter. I just looked randomly at a '96 XJ to find the one I linked. Link to comment Share on other sites More sharing options...
91Pioneer Posted April 2, 2016 Author Share Posted April 2, 2016 Cool, Gates' site has a spot where you can input your VIN and it shows you all the parts they make for the vehicle. According to them the 38109 grooved and 38042 smooth are the pulleys they make that fit. They don't specify w/AC or without though. Link to comment Share on other sites More sharing options...
91Pioneer Posted April 3, 2016 Author Share Posted April 3, 2016 So I was using a piece of hose and mechanics stethoscope to diagnose where the noise is coming from and it's been extremely tough to figure out the noise source. Now I'm kinda thinking it could be the water pump. It's a super high pitched squeal that is duplicated by starting the engine when the engine is warm. It happens every time for 1-3 seconds on startup. The pump does not appear to be weeping coolant out the bottom and appears to be older, possibly original, I couldn't say. I tried wiggling the WP pulley by hand and it seemed tight but I didn't loosen the belt. The PO said he replaced the thermostat & gasket I would guess in the last year or two. Sigh. Argh. Jeeps. Link to comment Share on other sites More sharing options...
mik666 Posted April 4, 2016 Share Posted April 4, 2016 did you try a new belt? I had a similar problem until used a gator belt and now my squeal is gone/ silent Link to comment Share on other sites More sharing options...
91Pioneer Posted April 5, 2016 Author Share Posted April 5, 2016 I haven't checked the pulleys again since my last writing but I did place an order from RockAuto, no pulleys but I did order a new belt. They're not Gatorback anymore, they're Continental Elite 4060710 It's such a high pitched squeal that I'm pretty confident it's a bad bearing (metal on metal) sound but I figured I should change out the belt anyway. And when I have it off I can turn the pulleys by hand to see if I feel anything that isn't smooth. Link to comment Share on other sites More sharing options...
Sly_Jeeper Posted April 18, 2020 Share Posted April 18, 2020 I haven't checked the pulleys again since my last writing but I did place an order from RockAuto, no pulleys but I did order a new belt. They're not Gatorback anymore, they're Continental Elite 4060710 It's such a high pitched squeal that I'm pretty confident it's a bad bearing (metal on metal) sound but I figured I should change out the belt anyway. And when I have it off I can turn the pulleys by hand to see if I feel anything that isn't smooth. Old post i know but wondered if the water pump fixed the 1-3 second squeal at startup i have the same issue and have replaced the belt with the continental eliteSent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
91Pioneer Posted April 19, 2020 Author Share Posted April 19, 2020 21 hours ago, Sly_MJ said: Old post i know but wondered if the water pump fixed the 1-3 second squeal at startup i have the same issue and have replaced the belt with the continental elite I basically haven't driven my truck in a year and I still have the new belt in the package, so yeah haven't done a thing in 4 years LOL... Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now