I'm going to write down couple remarks pertaining to timing belt replacement. since it's still fresh in my memory. I'll attach pictures and add some comments. Thanks to Grego95 for his tips and encouragement.
So let's get to it.
Time required: whole afternoon if you do it first time, half the time thereafter, hopefully after reading this you can do it in about 3-5 hrs depending on your skill level.
I'm attaching a section of a service manual covering that as a reference. GET FAMILIAR WITH IT PRIOR TO THE JOB. My remarks will attempt to help you shorten the time involved and eliminate guesswork.
I ASSUME NO RESPONSIBILITY FOR ERRORS AND OMISSIONS ON MY PART ALTHOUGH EVERY EFFORT HAS BEEN MADE TO MAKE SURE THE DESCRIPTION IS CORRECT.
Engine is 3.5L, Magnum SXT...
1. drain the coolant by turning the petcock at bottom left corner of the rad (from the front), drain tube is right below it sticking out at the bottom of a bumper, expect about 5 qts.
2. squeeze the clamps, remove the S shaped hose running from the rad to the engine (top one).
3. unplug and remove the rad's fan assembly (2 screws at each side) lift it straight up
now you have plenty of room to work with...
4. attach a vise grip to the bottom of the serpentine belt tensioner pull to the left to relax the belt, remove the belt from the alternator pulley while still holding the tensioner, slowly return the tensioner to the previous position...
5. block the harmonic balancer with a screwdriver and loosen, that's what I did, (or remove) the center bolt enough to be able to unscrew it by hand
6. attach a balancer puller to the bottom pulley (3 arm type) and either back up the pulley about 2/3 of an inch or remove it completely, my puller sucked so I ended up sliding it back just enough to give myself some room, without that you will not be able to remove the 3 bolts behind the wheel and remove the bottom cover
6. remove all the bolts from the bottom cover, let it hang or remove it
7. remove the serpentine belt tensioner bolt, remove the tensioner and then all the top cover bolts around, remove the cover
8. inspect the inside, turn the engine by hand so the bottom sprocket mark (bump) is aligned with the reference point located at about 2pm position relative to the crank sprocket, line them up, then check your timing marks on camshafts sprockets, inspect the belt, mine was 1 notch off on the right and about 2 notches on the left, belt partially shaved on 1 side, water pump leaking from the bearing seal... so far so good, LOL
9. unscrew and remove hydraulic tensioner (actuator) bolts (bottom left, from underneath the engine housing), check it for oil leak, if suspect replace with a new one
10. remove the timing belt (I went around the bottom cover/balancer wheel)
11. blow all clean with the compressed air (or use the paint brush)
12. precisely align crank sprocket to the mark at the bottom, same with both cam sprockets - turn them slightly left or right to line up with marks on top
13. replace the water pump (about 12 bolts around the housing), wipe the contact surfaces, put the new rubber gasket into the new pump and install it
14. replace the tensioner pulley (1 bolt) with a new one if there's play, I did that regardless
15. put the hydraulic tensioner in the vise or a metal clamp and very slowly (read the manual) squeeze the tensioner actuator back into the housing, install a pin to lock it, reinstall it with the pin in place, do not tighten the bolts yet, just enough to hold it in place, now you should be ready to put the belt in
16. run the belt as it was before - around the pulleys without disturbing the wheels/marks.
Hint: to obtain the proper alignment I had to turn the right cam sprocket 2/3 of a tooth to the right and the left about a full tooth, tightening the belt will turn them couterclockwise and move marks forward (to the left) slightly, this is trial and error part, may take a little bit of time to get it right but eventually you will get it in the proper position. Run the belt tightly on the right side, left side with be taken care of by the tensioner... Once the belt is in place start tightening the actuators' bolts, you will notice the belt tension turns the cam sprockets slightly, hopefully enough to align with the marks. In my case the right side ended up on the dot, left one about 1/2 tooth short of a mark. I consider it ok as the belt relaxation/tension will align it on its own. Right side has to be on the dot as this is where the cam sensor sits and gets the signal from (tone wheel behind the cam sprocket). Pay attention not to move cam sprockets more then 2-3 teeth if you have not removed rocker assembly, they are still under the spring load (valve springs) and beyond 3 teeth movement may suddenly jump 90 degs. You can turn it back into place though, but beware that this jump may cause internal contact between valves and pistons.
17. slowly turn the crank couple revolutions to make sure the belt tension is evenly distributed and the marks lined up. I used a flat screwdriver placed between a tensioner pulley and the actuatior to add to the tension to see how it affects the alignment. If everything is ok release the actuator pin. Turn the crank by hand a few more revolutions. If the alignment is correct you are DONE.
Reassembly is in the reverse order:
top cover, bottom cover, reinstall/tighten the balancer wheel, serpentine tensioner, serpentine belt, fan assembly, cooling system hose (tighten the petcock), fill it up with a new coolant...
Hopefully you will save yourself several hundred bucks. I got parts from rockauto.com. Gates timing belt kit (belt + tensioner pulley), Gates water pump (comes with the gasket), serpentine belt... and couple other things. The bill was VERY reasonable (around 160 for timing related parts). I was quoted close to a grand for the job, parts incl. by more then 3 shops (dealer incl.).
Final word: this is NOT a very difficult job. Aside from the balancer puller no special tools required. It's just time consuming... Have fun.
I hope you will find the above useful.
PS. you may also have a look here: http://www.moparmagazine.com/2010/ju...placement.html
Last edited by proxyx99; 10-29-2010 at 03:25 AM.
Very nice write up, thanks for sharing !!!!
Iam abought to change my timing belt and water pump the pdf attached to this post says
CAUTION: The 3.5L is NOT a freewheeling engine. Therefore, loosen the valve train rocker assemblies
before servicing the timing drive. Does this have to be done when replacing the timing belt? or can i skip this?
I know this is an older post but I went through this over the weekend and this write up helped out a lot. I was able to follow it to get the job done without too much trouble. The only thing I want to mention is make sure you get the correct puller to remove the Harmonic Balancer/Crankshaft Damper. I was able to rent it from my local auto parts store, just have to ask for it (I paid for it up front then was refunded when returned the puller). Also make sure to put the puller in the correct location. If look at the Balancer Removal picture (include in the write up above) it shows where to pull from. There are three indentions on the back side of the pulley that you cannot see which is where the arms of the puller should sit. DO NOT put the puller on the outside of the balancer pulley (where the serpentine belt goes). If you do this you will most likely wreck the pulley and have to get a new one which is not easy to find for the 3.5L. When I put the pulley back on I was able to heat it up a little with a torch then tap it on to the crankshaft enough to pull it on the rest of the way with the bolt.
2007 Dodge Magnum SXT 3.5L, 22" MHT Foose Nitrous, K&N CAI