This is a How-To to change out a Belt Tensioner on the 3.7L. With it the serpentine belt will be removed and this can be a how-to at the same time by ignoring and skipping steps for the belt tensioner.
I am writing this based off my experience and am not saying this is the proper way as I am not a professsionl. I AM NOT LIABLE FOR DAMAGES TO YOUR JEEP OR YOURSSELF...moving on haha:
Here is the 3.7L Belt Drive Pattern and which pulley goes to what
Tools Needed:
Flat Head Screwdriver
T20 Torx Screwdriver
3/8" & 1/4" Drive Ratchet
2" 1/4" Extension
5/8" Socket
13mm Socket
10mm Socket
8mm Socket
About 2-3 hours of time
1) Open Hood
2) Remove Negative Battery Cable
3) Move Hood Release Cable out of the way to remove the grille
4) Remove the Grille
Remove plastic fasteners and lift top over the hood bump stops, undo clips from atop headlight housing and use flat head screwdriver to the hidden clip off the side of the headlight housing, pull towards you and set aside.
Tricky Clip
5) Remove Headlight Housing
Using the T20 torx screwdriver remove the 3 screws mounting the housing, then unplug headlights/fog light via quarter-turn counter-clockwise.
(Love the guard as it creates a chair for me haha)
6) Remove the Coolant/Wiper Fluid Tank
Using the T20 torx screwdriver remove the four screws mounting the tank, unscrew the radiator cap a quarter-turn and remove hose, unplug wiper pump connector via using the torx screwdriver to poke the hole and pulling up on the connector and remove hoses (90degree hose can be removed after tank is outside the engine bay, wiper fluid will slowly drain after removal of 90degree hose).
Top two screws
Wiper Connector
Driver's Side Bottom Screw
Passenger's Side Bottom Screw
7) Remove Fan Shroud
Using a 8mm socket remove the three screws mounting the fan shroud, after screws are removed lift shroud enough to unplug the fan's connector (use the flathead to pry the clip and pull out), then using the 10mm socket remove the bolt securing the wire harness connector and remove wire from shroud, set aside shroud.
Driver's Side Screw
Passenger's Side Screw
Bottom Screw (AC Lines are secured here)
Fan's Connector (put flathead's tip where red dash is)
Wire Harness Connector's Bolt
Remove Serpentine Belt
Using a 5/8" socket (and a pipe extension) "tighten" the ribbed pulley (left pulley) on the belt tensioner (this goes against the torsion spring in the tensioner and releases pressure off the belt) and remove belt off of a pulley, work belt out of the engine bay.
9) Remove Belt Tensioner
Using a 5/8" socket removed the ribbed pulley's bolt from the belt tensioner (this opens up the space needed to access the bolt mounting the belt tensioner), using a 13mm socket (and pipe extension) remove the bolt securing the old belt tensioner(it may be very tight, mine needed my breaker bar pipe extension).
Belt Tensioner Mounting Bolt
Belt Tensioner Removed (leave circled alone, it's the alignment and bracing bolt for the tensioner)
9) Install New Belt Tensioner
I bought an AC Delco Belt Tensioner, which has a different size tensioner bolt size (from 5/8" to 13mm).
10) Re-install the Serpentine belt
Re-wrap the serpentine belt around the pulleys as shown in the belt drive pattern diagram leaving one pulley unwrapped until tensioner is "tightened", using the required bolt size, "tighten" the ribbed pulley to allow enough room to wrap the belt around the final pulley (I liked using the alternator pulley as it was small on the top). Ensuring nothing is in the fan's path, re-install the negative battery cable and test run the new pulley and/or belt. If everything checks out, remove negative battery cable again.
3.7L Belt Drive Pattern Diagram
Re-installed Serpentine Belt
11) Re-install the Fan Shroud and Connectors
12) Re-install the Coolant/Wiper Fluid Tank, Hoses, and Wiper Pump Connector
13) Re-install the Headlight Housings
14) Re-install the Grille
15) Re-install the Negative Battery Cable
16) Test run
Continue enjoying the KK for many more miles!
Please let me know if there should be any additions or changes to this how-to. Thank you for taking the time to read this!