Changing the Timing Belt

Last Updated - October 10th, 2004

Car won't start?  You've got fuel.  You've got spark.  Sounds like your timing belt broke.  Or perhaps you're the careful planning type and you just know it's time the change the belt.  Either way, here's how to tackle this project.


Difficulty:    

Time Investment:  Full Day/Weekend


Go to Pictures

Go to Instructions

Go to Tools & Supplies

Go to Notes


Pictures:

Click on a picture to enlarge it

This is the belt cover visible from behind the passenger side tire.
Jacking up the engine with a floor jack and wooden blocks
Here's a view of the serpentine belt & idler pulley
A/C Belt and tensioner pulley
Using an offset box end wrench to remove the serpentine belt
Here's the belt around the crank pulley
A/C tensioner & pulley
Alternator
Crank pulley...  an underdrive pulley from Forward Motion to be exact
Tubes connecting to plenum
Side motor mount
Front view of side motor mount
Side motor mount arm bracket with insert removed
Arm bracket mounting plate
Another shot of the arm bracket mounting plate.
Idler pulley (in the middle)
A/C tensioner being removed
Side mount insert, crank pulley, and idler pulley
A/C tensioner and arm bracket
A/C Compressor
"Hidden" bolt in the middle of the A/C compressor bracket
Compressor tied against radiator
A/C mounting bracket
Side mounting plate connected to the power steering pump
A 1/2" drive socket with a 3/8" to 1/2" adapter on a 3/8" ratchet is just the right length to get the bolts off the power steering pump.  A standard 3/8" deepwell is too long and a 1/2" socket is too short.
Removing the bolts through the holes in the power steering pump pulley
This is a shot of the front upper timing cover.  The cover is made of 3 pieces.
Shot of the crank after the crank pulley was removed
The mounting plate after everything has been unbolted from it
The mouting plate pulls out to reveal the center portion of the timing cover.
The full shot of the timing setup on a spare engine
The rear head markings line up.
The front head markings line up.
The crank markings line up.
Shot of timing components in car from top
Shot of timing components in car from bottom


Here is a diagram of the motor mount assembly  from the 1992 Chrysler FSM.
Here is a diagram of the bolts on the timing cover from the 1992 Chrysler FSM.
Here is a diagram of the timing components from the 1992 Chrysler FSM.
Here's a drawing of the tensioner and spring from the 1992 Chrysler FSM.  Not that the spring goes in the SIDE hole of the tensioner pulley (there is another to the right).


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Here's a diagram of the timing belt routing from the 1992 Chrysler FSM.





Instructions:

1.  Jack the car up & put it on stands.

2.  Remove the front passenger tire.

3.  Remove the under car belt shield.

4.  Disconnect the battery.

5.  Disconnect the ignition coil (wiring hareness side).

6.  Using the floor jack and a wood block, jack up and support the oil pan.
You'll use this to support the engine and also to lower and raise it to get better access to the parts you have to remove.

7.  Drain the coolant.

8.  Remove the passenger side radiator hose.

9.  Remove the serpentine & A/C belts.  (See the accessory belt page for details.)

10.  Remove the side motor mount.

11.  Remove the side mount arm bracket.

12.  Remove the crank pulley.
Removing the crank pulley can be a royal pain.  Hands down, the easiest way to get the bolt out is with a GOOD air impact wrench.  A el cheapo may not have enough power to do it. 

If you have a manual transmission, you can put the car in gear and have someone else pump up the brakes and hold them tight.  Meanwhile, you can take a socket & breaker bar to the bolt.  That will ususally work although you will most likely have to stand & bounce on your breaker bar.  Because you are using a long extension, it is possible that doing this will actually break your socket depending upon how good your set is.  Here's a pic Mike took after he broke one after trying this on his wife's 2000 Eclipse GT (of course it's a 3.0).  It pretty clearly shows the difference between a good and a cheap socket.

You can also get or build a pulley tool that goes through the side holes in the pulley while a breaker bar with a long extension is used on the center bolt.  This is probably the "right" way to do it if you don't have an impact wrench.

Another option, the easiest, and by far the most dangerous one, is to use the starter to do the work for you.  It puts out a LOT of torque and is more than up to the challenge.  To do this, put the socket over the bolt and rig up your breaker bar so that it is resting against the control arm such that it will be stopped if the engine rotates forward.  Rotate the engine yourself and make sure there is no play in the setup.  You don't want anything to slap and you certainly don't want it to slip off.  Double check to make sure the ignition coil is disconnected.  Hook the battery back up.  Get any onlookers out of that area.  Crank the motor briefly.  It could take 2 tries if you just hear a click the first time.  Re-disconnect the battery.  The bolt should be out.  If you choose to use this method, you do so at your own risk because it is clearly a hazardous approach.  When you turn that key, something is going to give.  The socket could explode.  The breaker bar could slip and go flying.  The starter could also die... although that's not too likely.   This method has been used successfully on several cars, but don't even think about pointing a finger at KMP if it doesn't work for you, if you damage your car, or if you hurt yourself or someone else in the process.

Once that bolt is out, the pulley itself will most likely be stuck.  There are no other bolts holding it down.  The small ones you see hold it to the tortional damper... which comes off of the crank with the pulley.  Semi-gently, whack the pulley with a hammer top, bottom, left, right, and repeat that a few times.  After a few rounds, you should be able to get it wiggling.  Once that happens, it will pop off if you pull and wiggle enough.  The damper is heavier than you would expect if you've never seen one.  That said, you may find yourself on your butt after you heave on it a few times and it comes free.

Getting the bolt back on can be done via air impact wrench, or the manual trans/brake way.  If you have an automatic, you're going to need a pulley tool or an impact wrench.

13.  Remove the idler pulley.

14.  Remove the A/C tensioner assmebly (3 bolts & pulley).

15.  Remove the mount plate that holds the arm bracket.

16.  Remove the 4 bolts holding the A/C compressor.

17. Use cable ties or a piece of rope to tie the compressor up away from the bracket.
(You don't have to discharge the system, but want it clear of the bracket.)

18. Remove the A/C mounting bracket.
Don't forget the hidden bolt in the middle of the bracket.

19.  Remove the alternator.

20.  Remove the front 2 bolts holding the PS pump to the side of the remaining plate where the motor mount brackets connect. 
The socket goes through holes in the PS pulley.  The absolute best way to do this is to put a 3/8" to 1/2" adapter on a 3/8" ratchet and use a 1/2" drive socket.  That adapter and the length of the 1/2" drive socket is just perfect to get to this bolt.  A 1/2" ratchet alone is difficult to maneuver and is too short to reach the bolt.  A 3/8" drive socket is too short and a longwell is too long.

21.  Remove bolts from the remaining plate.
It's not going to come off yet.

22.  Pull the plate back and use a 1/4" ratchet to get the bolts out of the timing belt cover. The timing belt cover comes off in 3 pieces. The front one and rear one will come off without the plate.  The center one takes a little work. Once all of the bolts are out, it will come out with the plate. (The other option here is to remove the PS pump. Having done it both ways, I recommend this method.)

23. Put the crank bolt back in and use it to turn the crank so that the timing marks line up. This will put the cams in somewhat neutral positions.

24. Loosen the bolt holding the tensioner pulley.

25. Using a pair of vice grips, release pull the end of the timing spring out from the peg on the water pump.
When reassembling, remember that the spring goes in the side hole of the tensioner, not the front hole.

26.  Remove the timing belt.

27.  Replace the water pump if desired.
If you replace the water pump, make sure to drain the radiator first.  Also be very careful not to strip the bolts that hold the front and back of the water pump together.  They strip very easily. 

28.  Install the new timing belt.
Rotate the camsprockets and crankshaft so that all of the timing marks line up.  Use a large wrench on the cam sprockets because the valve springs have a lot of tension and will want to abruptly cause the cam to rotate.  If you aren't holding on or are using a little wrench (or worse, a ratchet), thye may throw the wrench across the room.  Been there.  Done that.

Then rotate the crank sprocket about 1 tooth counter-clockwise. Wrap the belt under the crank sprocket, up over the front cam sprocket and down under the water pump. Now rotate the crank sprocket until the crank marks line up (the cams shouldn't move).  If you do this right, there should now be just a little tension on the front part of the belt and you can wrap the rest of the belt around the other cam sprocket and the tensioner.  Too much tension and it will slip.  The goal is just to get the slack out of the front.

Once the belt is on, hook the spring back up with your vice grips and then turn the engine over using the crank spocket a couple of rotations.  If the marks line up still, tighten the tensioner down, give it a couple more rotations, check it again.  If it still lines up, you're done.  If it skipped a tooth in there, try again. 

29.  Reassemble in reverse order.

Tools & Supplies:

  • Air impact wrench (recommended) or pulley tool - One is required for automatics.
  • Air ratchet (recommended)
  • 1/4", 3/8", and 1/2" ratchets/sockets with multiple extensions for the 3/8" and 1/2" wrenches.
  • 1/2" drive breaker bar
  • 1/2" drive 22mm Socket (Crank Bolt)
  • 15mm offset box end wrench or serpentine belt tool
  • Channel locks or large pliars for radiator hose clamps
  • Set of offset box end wrenches (12mm, 13mm, 14mm, and 15mm are the most helpful)
  • New timing belt and/or water pump


 Notes:

  • Contrary to what you may have read elsewhere or considered, you will not eek out high end performance or low end torque by setting the cam a full tooth off in either direction.  1 tooth equates to about 9 degrees.  To fine tune the power band, you would want to adjust the timing +/- 5 degrees max.  It is possible however based on the sprockets, and belt you are using for the marks to be a small fraction of a tooth off.  Just make sure it is as close as possible.
  • The Chrysler version of the 12v 6G72 SOHC is a non-interference engine meaning that no matter what you do, the valves are not going to smash into the pistons.  If you bump up the compression to 10:1 or are working with a 3.0 engine from a Mitsubishi Montero or Diamante, you do have an interference engine and you will need to take extreme car to make sure the cams don't rotate while the belt is off.