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Drive Belts / Idler Pulley / Tensioner Pulley - REPLACEMENT

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62K views 60 replies 34 participants last post by  Carlo06M5  
#1 ·
Hello Team,
Just thought I'd create a pictorial DIY for the drive belt, idler pulley, and tensioner pulleys replacement. I searched and searched and freaking searched to find a complete guide to accomplishing this task and only came up with bits and pieces. Hopefully someone else will find this and get some benefit. Everything I wanted to replace came in under $100 shipped (Amazon Prime) and I did this because on cold-starts, it sounded like a belt was squealing and was quite embarrassing. As time passed, it got worse. So here we go.

Parts Needed:
QTY (1) Waterpump/Alternator Belt: PN 11287838226 (Continental 4060563)
QTY (1) AC/Power Steering Belt: PN 11287835483 (Continental 4060427)
QTY (1) Idler Pulley: PN 11287841228 (Gates 38069)
QTY (2) Tensioner Pulley Only: PN (Dayco 89113)




Tools Needed:
T25 Torx
T30 Torx
16mm Socket
14mm Socket
Long Breaker Bar
Socket Wrench
Pick

*NOTE: A lot of pics are crappy. I used my phone and wasn't trying too hard.

1. Remove the metal radiator cover with your T30 torx:




2. Remove the plastic radiator cover with your T25 torx:




3. Vacuum all the crap off of the radiator if possible:



*If you look down between the radiator and the AC condenser core, you may see there is a ton of leaves and debris. I had a bunch, and before I buttoned everything up, I vacuumed it all out as best as possible. I searched and found that some people take their radiator out to do this, but I was not prepared to change the coolant, so I figured a way around. All you have to do, is pull up the AC condenser core about 3 inches and fish a small vacuum nozzle down there and suck it out.



4. Time to remove the fan. On the drivers (LH) side of the fan, there is an electrical connector. Pinch the connector on its sides and pull upward to release. Swing the connector and cable out of your way.




5. The fan has two tabs that pivot forward and back and rest into slots on the radiator mount, one on each side. To remove the fan, you will need to lift up about a half inch, and flip these tabs rearward toward the engine accordingly, to be able to clear the radiator hoses. While lifting the fan out, you need to hold back the cables and hoses that normally rest under the radiator support and on top of the fan. Be careful and be patient. You will eventually maneuver it out.



Here is a picture of what one of the pivot tabs look like (mine was missing the drivers side, so this is the passenger side):



Here is what the fan mount looks like that the pivot tab rests in:



Here are a couple pics that represent the articulation of the pivot tabs:




6. At this point, you should have plenty access to get to the pulleys and belts. To protect your radiator from dents and bruises, cut out a sheet of cardboard, if available, and stuff it behind radiator. I laid my fan on top of a box, traced the outline, and used a box cutter to cut out the shape.





7. Remove the pulley dust caps. You will not reuse these unless you bought OEM stuff, which I didn't.

 
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#2 · (Edited)
8. Before tearing into the next steps, take a moment to analyze how the belts are routed and admire the S85 in all its glory. It would behoove you to make a simple sketch of the belt routing as well. Here, I did it for you:



9. Begin by removing the idler pulley. Use a 16mm socket wrench and loosen the bolt on the idler pulley. Then, place a 14mm socket on a breaker bar on the tensioner pulley below the idler pulley. Pull the breaker bar towards the drivers side (clockwise) to loosen slack on the belt. While doing this, finish loosening the idler pulley and remove it completely. The belt should now have enough slack to remove.




Here is a side-by-side shot of the OE and Gates idler pulley:



Here is my OE belt. Still looked great for its age:




Here are a couple side-by-side shots of the OE and the Continental belts:




10. You can now remove the pulley on the belt tensioner. Use a 14mm socket wrench and turn the bolt toward the passenger side of the car (counterclockwise). Remove pulley.

OE:



OE (left) & Dayco (right):



11. Go ahead and install the new tensioner pulley and hand tighten.

12. Now we are going to remove the waterpump/alternator belt. Use your 14mm socket on the breaker bar, place on the tensioner pulley bolt and turn toward the drivers side (clockwise). This releases enough tension that you can slip the belt out from around the tensioner. Remove belt.




13. Remove/Replace tensioner pulley the same way you did the previous one.

Here are some pictures of my OE belt:




Here is a side-by-side shot of the OE (left) vs Continental (right):



14. Now we are going to start to put everything back together. Install the waterpump/alternator belt by routing it around the appropriate pulleys and leaving the tensioner pulley last. Use your 14mm breaker bar turning the tensioner clockwise and work the belt on the tensioner pulley. Its going to be a bit difficult as the belt is new and hasn't stretched any.



15. Now install the AC/power steering belt leaving the tensioner pulley for last. Again, use your 14mm breaker bar turning the tensioner clockwise and slipping the belt on.

16. Now we need to install the new idler pulley. If you look at the back of the pulley and where it mounts on the motor, there is a small nipple and corresponding indention where it fits. Be sure to line this up when installing. You will need to use the 14mm breaker bar on the tensioner and the 16mm socket wrench at the same time to install the idler pulley. Hand tighten.



17. Check your work and make sure the belt grooves are in their appropriate grooves on each pulley.



18. Reinstall the fan the opposite of removal. Be sure to plug the electrical connector back in.

19. Reinstall the plastic radiator cover with the T25 torx and hook the hoses back into their spots.

20. Reinstall the metal radiator cover with the T30 torx and hook the cables/wires into their spots.

30. Start your car and check for any mishaps.

31. Stand back and admire a job well done:

 
#7 ·
Good move. I just had mine done as part of the rod bearing replacement and internal VANOS pressure line replacement. This rushing sound of worn bearings has disappeared completely. Very satisfying. We also discovered a leaking water pump bearing. Very subtle as it was dripping out of the weep hole. Did you check the pump? Very obscure and something really look for (from the bottom).

Image
 
#8 ·
Good move. I just had mine done as part of the rod bearing replacement and internal VANOS pressure line replacement. This rushing sound of worn bearings has disappeared completely. Very satisfying. We also discovered a leaking water pump bearing. Very subtle as it was dripping out of the weep hole. Did you check the pump? Very obscure and something really look for (from the bottom).
No, but thanks for the heads-up. I will bust out the inspection mirror this weekend to see.
 
#12 ·
The job took me, from 4:01 PM (when the car was on ramps) till 6:51 PM (when I started her up), so roughly 3 hours. I did all work from the top because why the heck would I want to lay on the ground the whole time and deal with taking off like 100 screws for the bottom panel. My time included snapping a bunch of pics, my power going out at the hours for about 30 minutes, and cleaning out all the trash in front of the radiator. So, realistically, I believe I could have done this in 2 hours or less.
 
#15 ·
thanks, added to master DIY in maintenance section.
 
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#18 ·
I just got done doing this, checked the grooves to make sure everything was correct. Put everything back together and car starts and runs smooth. So I put everything back together and tried to go for a drive, the power steering is very rough and makes squeal sounds when I turn the wheel. Did I do something wrong? The car revs fine with no squeals, just the power steering has the problem. I am waiting for the car to cool down so I can take a look at it again. Any help would be appreciated. Thanks
 
#20 ·
The steering was fine until I did the change out. I will check the fluid though. Does the new belts have a certain direction that they need to be installed? I just made sure the grooves lined up. Going to start taking it apart again now....
 
#21 ·
Just checked, fluid is fine, I tried to turn the AC on and started to squeal real loud and smell burnt rubber....
 
#23 ·
Thats exactly what it was. Its weird, I have done this on other cars and I never had to tension up after I was done. Isn' that what the tensioner is suppose to do on its own? so I ended up taking the breaker bar and give it a tug to the left (counter clock wise) without loosening the nut and the belt was tighter and everything is ok again. I don't know if my tensior is worn, but I guess time will tell. Thanks!!!
 
#24 · (Edited)

Attachments

#25 ·
Bump for mid 2017 update:

if you're looking for OEM-grade for the two idler pulleys, you can use INA 11281440237 (made in germany) and just remove the screw/plate that it comes with. It is identical to the one that comes with the oem tensioners, which are also made by INA. I paid about 20 bucks a pop.

Great find. Thanks for sharing. :cheers:
 
#29 · (Edited)
Hi everyone, long time lurker, needing some advice now that my car is of an age and mileage that more serious maintenance is required.

I'm at the beginning of trying to do this DIY as part of an alternator replacement and really struggling to remove the fan per the instructions. There's nothing wrong with the steps that are laid out but I'm having the hardest time getting to the "wing" on the passenger side of the fan housing (this is a US LHD car, 2006, for what that's worth). There's a radiator hose that you have to clear to remove the fan and it's that same hose that is giving me fits to rotate that wing back out of the way. I can't get my hand down in there enough to give me good enough grip. I even got my wife to try rotating the wing back and she was unable to.

Any tips for this from people that have done this? Is it easier from down below, since I'm going to have to remove things down there anyway for the alternator replacement? I'm nearly desperate enough to consider removing the radiator to do this, so any guidance would be much appreciated.

Update: Working with a long screwdriver (as noted elsewhere) did the trick to unclick the tab, as well as to help rotate the tab from between the radiator hoses. I'm going to have to figure out how to click it back in once I'm done, which seems like it will also be fun.
 
#32 ·
I just replaced my alternator as well. I also added a thick 4 gauge ground cable bolted from the bottom of the alternator to the ground bolt on the chasis used for jump starts.

When i was down there... i noticed that it appeared to be the 2nd alternator replacement at 56k miles. I dont remember replacing it before but maybe the dealer or a previous owner did before i bought it at 20k miles.

so anyways, i believe the engine ground cable is likely bad and caused the alternator to fail really quickly due to the increased resistance. I havent checked the engine ground cable located on passenger side on the bottom right below the egr valve because its hard to reach but i do have a power steering hose fluid leak exactly above that engine ground cable.

after replacing my alternator and adding the additional ground cable from alternator to chassis ...... i am frankly shocked at the results. Not only am i getting a much better highway mileage of 16.5mpg and 11mpg city (compared to 6-8mpg city) but the car runs soooo better in terms of performance. It hauls ***. Incredible.
 
#31 ·
^ Just did belts.
It helps to remove the Passenger Air Box.
That gives you room to to deal with the Wing Latch on the passenger side of the Radiator Fan Shroud.

Whole job can be done from top, but I removed the bottom cover, to clean inspect everything.
When reinstalling the Fan Shroud, its nice to inspect from bottom to assure Bottom Locator Tabs engage properly.
936201
936202
 
#35 ·
Be wary of just replacing the pulleys.
I have found that the tensioner brackets themselves have a bearing where they mount to the block, this was quite seized on mine so the tensioner arm was not moving as it should. Originally thought I'd broken the tensioner strut so bought a new one, whilst replacing it I noticed the bracket was very stiff.
New belts squealed, I will have to replace the whole bracket now.
Original belt/pulleys from 2007 and 145k miles.