Figured I'd put this out there for anyone who was interested in changing their own engine belts but wasn't feeling very comfortable. I have a 2007 M35x so, at the least, this would be the same for the 2006 M35. I haven't seen the 08/09 car so I can't say if this process is any different but it should be since I believe it's the EXACT same motor. This should give you the general idea though.

*Disclaimer* - I am not liable for anything you do to your car. This is just a basic walkthrough.

I took the pics with my HTC EVO 4G from Sprint (love this phone). End of shameless plug lol.

Task: Change the engine belts
Time: About an hour and a half if you work slowly and take caution
Tools/Supplies Needed:

• 10mm socket + maybe one extension to take off the splash shield and first part of the air intake system
• 12mm (I believe - may be 14mm) socket to loosen tensioner pulleys
• Both drive belts - I got the 60k maintenance kit from Sewell Infiniti (link) which had these in the kit. The part numbers for the belts are (according to google since Sewell doesn't list them on the kit information) 11920-AG900 (smaller belt) and 11720-4P10A (larger belt).
• Car jack and proper support (so you don't get crushed)

Process:

1) Jack the car up in a safe manner so you can get under it to do the work.

2) Remove the front underbody splash shield using the 10mm socket + extension (if need be):



You will be then left with this:



3) Remove the first part of the air intake system to give yourself some room from the top and to allow in more light (helped me - this might be an optional step)



4) Locate the tensioner pulley bolts







5)

mgokool wrote:IlyaKol, great writeup! What you might wanna add though, before you loosen the tensioner bolts that move the pulley's up and down, you we're supposed to loosen the bolt in the center of the tensioner's FIRST. ((seen in your 1st pic under step #4 looking from the top-down!))

I ran into the same problem as you did, not being able to get the belt off, seemed like the tensioner won't move far enough downard to allow enough room...IT IS VERY IMPORTANT TO LOOSEN THAT BOLT ON EACH IDLER PULLEY *FIRST* BEFORE loosening the tensioner screws...otherwise you risk rounding up the tensioner bolt, stripping it or even snapping it!....its in the FSM and can easily be overlooked!

Anyone doing this, follow this step along with IlyaKol's original steps and you shouldn't have any problems!...

**loosen bolt on idler pulley -> loosen tensioner -> replace belts -> tighten tensioner -> tighten idler pulley bolt...**

HOPE THIS HELPS!

Loosen the bolts until the pulleys move all the way down and swap belts. To be honest with you, I couldn't get the main belt on no matter what I did and ended up stripping the bolt a little bit (the head part). I had the dealer do that belt for me. I got the smaller belt on fine. Not sure why I wasn't able to get the main one on because as far as I know the dealer used the belt I supplied them with (according to the paperwork).

6) Tighten the belts till they have the same or slightly tighter inflection as before.

7) If you have chirping when the car is running, you have to tighten the belts more. Otherwise, you are done.

great write up. When are the drive belts suppose to be changed usually? at the 60k mark?

I did mine at 53k, but 60k would be a good spot and then 120k I guess. After that, unless you plan to keep the car, I wouldn't touch em really.

I wish we had drive chains like the older M35/45's. From what I hear those never need to be replaced.

I've heard of timing chains but I've never heard of drive chains. Interesting. Yeah, I don't think those would need changing.

never heard of drive chains either. more info plz

Well maybe Im wrong. I heard someone saying they have drive chains instead of belts so maybe whoever told me that was confused as well.

Sounds like they were confused, I mean, some cars have timing belts instead of timing chains. You could technically put on a drive chain if you wanted (with quite a bit of expensive custom work), but it would still hane to be changed just like a motorcycle chain, because it wouldn't be constantly lubricated or protected from the environment. Also, "never have to change the chains" isn't necessarily true for timing chains (while it is true that they aren't a standard maintenance item like timing belts). Even old ones can break, and I have heard of a few newer ones breaking on Phaeton W12 engines. They can also wear, for instance, 2008 Cadillac CTSes have nylon timing chains, and several of them had to be changed under warranty due to premature wear. Cadillac later released an ECU flash or something that properly determines OCI (because people were changing their oil according to the light that was going 15K miles) and claim that will help, but I know of a 2008 Cadillac CTS that had the nylon timing chain replaced under warranty due to premature wear with an owner who changed the oil every 5K. That car also had two coils replaceud under warranty and a third die after the warranty was out, along with many other issues I mentioned in some other post on some other thread some time ago. Regardless, unless Cadillac's ECU flash also changed tolerances for the timing chain's stretching, that thing is practically a really expensive timing belt and that check engine light could be a big deal.

Also, to veer back toward the topic, it should be noted (as was recently discussed in another thread) that the 06-07 M45 have auto-tensioners and there is a bolt on them that should not be loosened or they will have to be replaced (according to the FSM). The procedure for changing the belts on the M45 is therefore totally different.

Good info in here. Thanks Dustin. I know Nissan chains in the VQ's are pretty strong, but didn't know they had things such as nylon chains, etc.

Yeah, I think the person was referring to timing chains. Oh well, happens.

The '07 M35x has a timing chain, correct?

All VQ's do as far as I know. Altima, Maxima, M35, G, Z...I believe they are all chain. There might be a few motor models that Nissan makes that are belt, but I believe as a whole Nissan is pretty much all timing chain.

IlyaKol wrote:The part numbers for the belts are (according to google since Sewell doesn't list them on the kit information) 11920-AG900 (smaller belt) and 11720-4P10A (larger belt).

my belt says 11720-4P102. it does not end with an A. Can anyone confirm this belt is the same?

I think mine did to, but the one I got didn't. It was probably one of those cases where it was superseded.

Thanks for the write up. Dealer wanted to change mine today for $260. I think i'll be doing this one myself. Any reason to avoid AutoZone belts? I can get both for $30 there.

Never used em so don't know...can't say. And you're welcome.

IlyaKol, great writeup! What you might wanna add though, before you loosen the tensioner bolts that move the pulley's up and down, you we're supposed to loosen the bolt in the center of the tensioner's FIRST. ((seen in your 1st pic under step #4 looking from the top-down!))

I ran into the same problem as you did, not being able to get the belt off, seemed like the tensioner won't move far enough downard to allow enough room...IT IS VERY IMPORTANT TO LOOSEN THAT BOLT ON EACH IDLER PULLEY *FIRST* BEFORE loosening the tensioner screws...otherwise you risk rounding up the tensioner bolt, stripping it or even snapping it!....its in the FSM and can easily be overlooked!

Anyone doing this, follow this step along with IlyaKol's original steps and you shouldn't have any problems!...

**loosen bolt on idler pulley -> loosen tensioner -> replace belts -> tighten tensioner -> tighten idler pulley bolt...**

HOPE THIS HELPS!

The00Dustin wrote:Sounds like they were confused, I mean, some cars have timing belts instead of timing chains. You could technically put on a drive chain if you wanted (with quite a bit of expensive custom work), but it would still hane to be changed just like a motorcycle chain, because it wouldn't be constantly lubricated or protected from the environment. Also, "never have to change the chains" isn't necessarily true for timing chains (while it is true that they aren't a standard maintenance item like timing belts). Even old ones can break, and I have heard of a few newer ones breaking on Phaeton W12 engines. They can also wear, for instance, 2008 Cadillac CTSes have nylon timing chains, and several of them had to be changed under warranty due to premature wear. Cadillac later released an ECU flash or something that properly determines OCI (because people were changing their oil according to the light that was going 15K miles) and claim that will help, but I know of a 2008 Cadillac CTS that had the nylon timing chain replaced under warranty due to premature wear with an owner who changed the oil every 5K. That car also had two coils replaceud under warranty and a third die after the warranty was out, along with many other issues I mentioned in some other post on some other thread some time ago. Regardless, unless Cadillac's ECU flash also changed tolerances for the timing chain's stretching, that thing is practically a really expensive timing belt and that check engine light could be a big deal.

Also, to veer back toward the topic, it should be noted (as was recently discussed in another thread) that the 06-07 M45 have auto-tensioners and there is a bolt on them that should not be loosened or they will have to be replaced (according to the FSM). The procedure for changing the belts on the M45 is therefore totally different.

LOL... I find it interesting you mention that... I am an M35 owner now after owning an '07 Cadillac CTS with 38K miles on it for only ONE month. Had the timing chains get ready to go on the car. ....

Covered under warranty or not.... I kid you not. I picked the CTS up from the Cadillac Service Center and drove directly over to the nearest Infiniti dealer.... It was a wrap.

Thanks Mgokool. I edited my instructions. Thanks.

IlyaKol wrote:Never used em so don't know...can't say. And you're welcome.

What About GoodYear Gatorback Poly V.. I heard and read they are pretty good and QUIET not like the oem nissan ones... I just ordered mine set of those on ebay yesterday, both for $ 28 shipped... Btw I dont agree with changing these belts at 60 K and then 120 K .. it all depends on the condition of the belt ( dried, cracks, misalligned causing damage to belt etc. ) belts should be checked and changed whenever these symptoms occur .


http://cgi.ebay.com/ebaymotors/ws/eBayI ... MEWNX%3AIT

IlyaKol wrote:Thanks Mgokool. I edited my instructions. Thanks.

The other thing I would add to your instructions is that you can change these belts from the top, there is no need to remove the bottom cover - you are creating needless work by raising your car and removing the under cover. I also would recommend using a 12mm ratchet wrench on the adjustment bolts - it makes the job easy.

This procedure is nicely layout out in M35 shop manual.

Yes you can use a ratchet, but trust me, from the bottom...access to the adjustment bolts is MUCH easier.

Smarter not harder is my motto. But to each their own. I'd rather take 10 minutes to take off the splash guard (I have a lift and air tools), than spend an extra 15 minutes battling trying to get the racket onto a bolt I can't see and can only feel, etc.

IlyaKol wrote:Yes you can use a ratchet, but trust me, from the bottom...access to the adjustment bolts is MUCH easier.

Smarter not harder is my motto. But to each their own. I'd rather take 10 minutes to take off the splash guard (I have a lift and air tools), than spend an extra 15 minutes battling trying to get the racket onto a bolt I can't see and can only feel, etc.

It took me 20 minutes to replace the belts. It is a very easy job. Read the shop manual.

You might want to reassess your smarter not harder motto. As I recall you could not get one of your belts off because you did not loosen the tensioner bolt -------read the shop manual.

IlyaKol wrote:Yes you can use a ratchet, but trust me, from the bottom...access to the adjustment bolts is MUCH easier.

Smarter not harder is my motto. But to each their own. I'd rather take 10 minutes to take off the splash guard (I have a lift and air tools), than spend an extra 15 minutes battling trying to get the racket onto a bolt I can't see and can only feel, etc.

Theres no doubt it can be done from above, but I agree with you IlyaKol...definately much easier from the below. I actually changed mine at the time I was doing my oil change...so really wasnt any extra work.

Hey are you from Dallas?
I heard about swewll so I guess about that
BTW can you help me to change my M35 spark plugs? I will pay your labor as you want.

thomasm35 wrote:

IlyaKol wrote:Yes you can use a ratchet, but trust me, from the bottom...access to the adjustment bolts is MUCH easier.

Smarter not harder is my motto. But to each their own. I'd rather take 10 minutes to take off the splash guard (I have a lift and air tools), than spend an extra 15 minutes battling trying to get the racket onto a bolt I can't see and can only feel, etc.

It took me 20 minutes to replace the belts. It is a very easy job. Read the shop manual.

You might want to reassess your smarter not harder motto. As I recall you could not get one of your belts off because you did not loosen the tensioner bolt -------read the shop manual.

What's with the attitude? (see bold)

If I didn't know to loosen the tensioner, going from the top or bottom wouldn't have made a difference so therefor your point is mute. Going from the bottom is still smarter as you have much more room to work with (and don't need to lean all over the front of the car and feel around for the tensioner bolts). I guess you're just an amazing human being who can do a belt change from the top in 20 minutes and never drop the wrench or the socket when trying to get it on the tensioner bolts. How long does it take you to swap an engine? 4 hours and a beer? Please...get real.

Bottom line, going form the bottom gives you a better view of everything. If you want to argue that, then you're just plain silly.

markboss wrote:Hey are you from Dallas?
I heard about swewll so I guess about that
BTW can you help me to change my M35 spark plugs? I will pay your labor as you want.

The location of most users is under their username.

I have changed these belts both from the bottom and the top - changing them from the top is much easier. Who is silly and has attitude?

Well then. You're just amazing.

I agree with thomas35
"there is no need to remove the bottom cover ..... recommend using a 12mm ratchet wrench on the adjustment bolts - it makes the job easy."

There is no need to remove bottom panel. There is plenty of room and the car is low enough to bend over from the top. Just guide the ratch on to the adjustment bolts with your fingers. Total job is less than 30 mins. Don't forget to loosen the nut in the middle of the idler/puller.

Excellent diagram at
http://www.justanswer.com/car/1o280-cha ... 6-m35.html

Wow. Epic first post there. You're really winning.

Too each his own...it takes ME (on my lift with air tools) all of 2 minutes to remove the bottom cover. If someone wants/or chooses to skip that step, by all means. Do it, and make a 'better' HowTo.

The influx of spaz's in this subforum has made me less willing to take the time to document anything in the future.

Just did both belts from the top. 20-30 minutes. One look at the pics on this link and you know exactly here the tensioner bolts are. No need to remove bottom cover. Unnecessary with the M35, perhaps better to do so with M45. Not everyone has a lift and you absolutely do not need one to do this quick repair.