HOW TO: change serpentine drive belt (3.7L)

Discussion in 'How To' started by Corwyyn, Dec 23, 2007.

  1. smallfish

    smallfish New Member

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    Just replaced mine today on a 02 with about 73000 miles...it had a long crack.

    Very important note: you have to get the OEM belt because the back of the belt has a hatched texture to make contact with the water pump pulley; using the aftermarket (Davco, gates, etc) which has a smooth back will cause belt slippage in a year or two. I have not put a part number here as you should give your vin number to your jeep dealer's parts guy to make you get the right belt.

    Other tools include a serpentine belt tool (a long flat bar and some sockets, including the 15mm for the idler tensioner pulley)(at sears for 30 dollars), and a 13mm 1/2 socket and handle(if you want to replace the belt tensioner which I'd recommend if you need to replace the belt). I tried getting away without the serpentine tool and it didn't work; withe the tool it is much easier!

    Be very careful about getting a aftermarket tensioner; I bought one at napa and the bearings had some play in them so make you check them at the counter before you pay for them! I ended up buying the oem part(insert part number here, made by davco) for about $100.

    1. Remove key from ignition and remove negative terminal from battery (your hands will be between the fan blades

    2. put 15mm socket in serpentine tool and put socket on the idler pulley on the left hand side. The tool should be pointing at about 1'o colock. (facing the rear) turn the tool clockwise to relieve tension on the belt so it can be slipped off the pulley.

    3. remove belt. The way I did it was to take off the end near the a/c compressor and pass it towards the right.

    *4. Compare the old belt with the new one to make sure it is identical in length, number of grooves, etc. Stop if they don't match exactly! Keep the old belt as a spare.

    5. Remove belt tensioner. You will need a breaker bar (I doubt there is room) or the serpentine belt tool to break the bolt loose (13mm). Then there is just enough room for a 3/8 or 1/2 handle to undo the bolt.

    6.Inspect old belt tensioner. make sure there is no bearing play, the pulleys spin smoothly, and it is quiet.

    7. Inspect new tensioner. no point putting one in with bearing play!

    8. pass new belt from left to right. make sure the back side is around the water pump (center) .

    9.install new tensioner. Manual says 40nm but i just tightened her good.

    10. with all the other pulleys correctly installed, use the serpentine tool to retract the tensioner pulley to give room to install the idler pulley.

    11. final check to make sure all pulleys are on as on the diagram, and all tools removed. reinstall negative terminal.

    12. start car to check everything is okay.

    13. put away old belt in back of car as a spare.

    14. pour yourself a cold one!
     
    Last edited: Dec 31, 2011
  2. lbpeter

    lbpeter New Member

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    Thanks for the instructions on how to change a serpentine belt. It was really as easy as stated on my 2002 Liberty. During the belt change, I noticed a wheel that has a crack, the one on the far right. It's not all the way through, rather just on the top. Is this cause for concern? It is the entire width. What is this and should it be fixed? (My mileage is 145,000)
     
  3. candpliberty

    candpliberty New Member

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    I would change it. I just repaired my neighbor's Grand Cherokee. Her Idler pulley completely fell out rendering her car inoperable. EVERYTHING runs off the serpentine!
     
  4. rockymountain

    rockymountain Full Access Member

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    Power steering pulley is intentionally like that. Why? I don't remember. Its normal.
     
  5. Jeep02Jeep

    Jeep02Jeep New Member

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    This post has been beyond helpful! Reading it, I'm now not sure if it really is my Serpentine belt that needs to be replaced or not.
    -02 Liberty
    - Hit 100k then 4 days later while driving through 109 degree weather in NV, my AC went out.
    - It started making a very loud noise when I started the car, but was fine while driving it.
    -3 days after that it squeals like a pig, and turns out the belt is completely stuck.

    It's parked in my driveway and I refuse to pay a tow truck and Jeep dealers to do something that ya'll can teach me, from personal experience. Hoping it's not my AC compressor, can't afford to fix that.

    Does this sound familiar?
     
  6. candpliberty

    candpliberty New Member

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    5 minutes to pop off the belt. before you do, Fire it up and see what isn't turning. I just did my a/c compressor. 500 bucks at Oreilly's! Since the compressor has a clutch, I'd guess it is something else. Hopefully a idler pulley, for your sake!
     
  7. Wahnsinn

    Wahnsinn New Member

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    Hopefully a quick question guys, I'm looking to switch out my belt and tensioner ('02 Limited, 4wd, tow package). When I'm looking down at the engine, it seems to me that I'd have to remove the fan in order to be able to remove/install the belt. Am I wrong and just looking at it incorrectly? It seems like the fan is directly connected to the water pump pulley (or whatever that pulley is in the top middle). Thanks!
     
  8. candpliberty

    candpliberty New Member

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    I have a 2006 v6 tow package 4x4. Did not remove shroud to replace serpentine belt.
     
  9. tjkj2002

    tjkj2002 Full Access Member

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    With HD cooling you still can remove the tensioner and change the belt,just alot less room to do it in and alot more colorfull words used when you get your arms stuck.
     
  10. Wahnsinn

    Wahnsinn New Member

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    Yeah, I think I was just picturing it wrong when I thought about how I would get the new belt on. Borrowed the belt tool from Oreilly's today, so I should get to it all tomorrow. Thanks again!

    ETA: They originally sold me the shorter 86" belt, turns out it was the 87" that I needed :) Finally got the new tensioner on this afternoon, had my son help me for a minute to hold the tensioner so I could get the belt onto all the pulleys. It is definitely a bear with the HD cooling setup, but it's on now. Hopefully go another 100k before I need to do that again.
     
    Last edited: Sep 28, 2012
  11. imamonkey

    imamonkey New Member

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    Thank you so much

    See that this was posted in 2007. This 2012 replying and saying thanks for your detailed post. A trip to the auto parts store, $34 and my Liberty is up and running again (install took 5 min or less).

    Again, thanks -- needed a break like this this week.
     
  12. pure_mahem

    pure_mahem New Member

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    Never used the wrench. Just srong armed it.