[Bimmer_Engineer]

Okay so I know I’m gonna feel like a real moron after this gets answered but try as I might I can’t get the belt back on my n54...see the attached pic. It feels like the belt is too short although i compared it to the belt I took off and they are the same length. I can get the tensioner fully bottomed out against the stop and the belt is still about 1.5” from going around the top tensioner pulley...any insight???

[nissubaru]

I believe this is the routing you want to use



Other than that, if I'm remembering correctly I found it easiest to run the belt fully and then slip it on the tensioner pulley last while putting weight on the tensioner to give me some slack.

Maybe get a second hand to hold the tensioner while you route the belt? A long breaker bar makes it easier if you're doing it alone, the shorter your ratchet the more difficult it is to hold the tension off.

Edit: Also make sure you didn't get the belt hung up on anything down towards the bottom. You should be able to get your hands down there and feel around. It took a little bit of maneuvering to get my belt to sit perfectly

Edit #2: Looking at it again, I think I used the pulley under the tensioner pulley as the last one to wrap around. Something about that one just seems easier to put on last.

[RSL]

+1, is your belt even around all of them? Obviously, make sure you got the right belt length.

Can't see if the tensioner is compressed (doesn't look like it), but fully compress it and use a pin or similar through the holes to hold it until the belt is installed. That spring is stout, make sure whatever you use is solid and has no chance of popping out. New belt is a somewhat snug fit even with the tensioner fully compressed. Get it routed and then pull the all slack out at the last pulley, make sure the ribs are in the grooves and that it's seated properly on all pulleys or you likely won't have enough slack to get it over the last one (tensioner or tensioner idler probably is best).

[Antetokounmpo]

Username does not check out apparently..

[Bimmer_Engineer]

Originally Posted by Antetokounmpo

Username does not check out apparently..

[OTO335i]

Originally Posted by Bimmer_Engineer

I believe there's a couple different ways the belt can be routed on our engines, i ran into the same issue the first time i replaced mine and i wasn't routing it correctly. I had found 2 different ways in Google for the N54, i guess it depends on what year the motor was made or something.

What part number is on the belt?

If that's not it, obviously user error is happening here.

[nissubaru]

Originally Posted by OTO335i

I believe there's a couple different ways the belt can be routed on our engines, i ran into the same issue the first time i replaced mine and i wasn't routing it correctly. I had found 2 different ways in Google for the N54, i guess it depends on what year the motor was made or something.

As far as I know there are two ways, this thread below is where I discovered this information

https://www.n54tech.com/forums/showthread.php?t=11957

I believe the problem with the original way of routing the belt was that it could potentially come in contact with the subframe so it was re-routed for better clearance. If this affects the length of the belt, I'm not sure. All I can say is I bought a Continental belt recently from FCPEuro and had no issues with fitment.

[feuer]

Is installer error. Old and new belts are same length. Change of username is in order.....

[Bimmer_Engineer]

Originally Posted by feuer

Is installer error. Old and new belts are same length. Change of username is in order.....

Just to clarify I’m not trolling you...the routing diagram on realoem and of pictures I’ve seen of n54 engines shows a different routing than what I ended up using...and I’m an engineer...I don’t typically do stuff half assed until I ensure the full assed way isn’t working for a valid reason...no point in reinventing the wheel or breaking something needlessly...

Originally Posted by Bimmer_Engineer

the routing diagram on realoem and of pictures I’ve seen of n54 engines shows a different routing than what I ended up using

Where do you keep seeing different belt routes..??

Please provide examples.

Originally Posted by nissubaru

I believe the problem with the original way of routing the belt was that it could potentially come in contact with the subframe so it was re-routed for better clearance.

How does rerouting the belt provide better clearance between the PS pulley and the subframe..??

[TheMidnightNarwhal]

Originally Posted by FCobra94

Where do you keep seeing different belt routes..??

Please provide examples.

How does rerouting the belt provide better clearance between the PS pulley and the subframe..??

The belt goes above the pull instead of crossing at the bottom I believe.

Here is the thread which was originally discussed and has the pics.

https://www.n54tech.com/forums/showthread.php?t=11957

[Bimmer_Engineer]

Originally Posted by TheMidnightNarwhal

The belt goes above the pull instead of crossing at the bottom I believe.

Here is the thread which was originally discussed and has the pics.

https://www.n54tech.com/forums/showthread.php?t=11957

+1

[feuer]

Originally Posted by TheMidnightNarwhal

The belt goes above the pull instead of crossing at the bottom I believe.

Here is the thread which was originally discussed and has the pics.

https://www.n54tech.com/forums/showthread.php?t=11957

Even if so this "alternative" routing exist as an option, won't prevent belt-pulley damage if they contact the subframe. I have done many belts, including 3 on my personal n54, only one routing I know, same as seen on the technical photo in the n54tech link you posted.

[TheMidnightNarwhal]

Originally Posted by feuer

Even if so this "alternative" routing exist as an option, won't prevent belt-pulley damage if they contact the subframe. I have done many belts, including 3 on my personal n54, only one routing I know, same as seen on the technical photo in the n54tech link you posted.

Yeah now that I've read the other thread I think that the N54 picture was just like a render pre-render of what the engine would have been and when it came out the actual belt routing is the one from realOEM and how yours and everyone else's is already on the engine .

[E92Monroy]

Originally Posted by Bimmer_Engineer

Okay so I know I’m gonna feel like a real moron after this gets answered but try as I might I can’t get the belt back on my n54...see the attached pic. It feels like the belt is too short although i compared it to the belt I took off and they are the same length. I can get the tensioner fully bottomed out against the stop and the belt is still about 1.5” from going around the top tensioner pulley...any insight???

Having the same issue any tips ? Or did you figure out what was the issue ?

[OTO335i]

Originally Posted by E92Monroy

Having the same issue any tips ? Or did you figure out what was the issue ?

Read through the whole thread. You're probably not routing it correctly, There's 2 different ways.

[nissubaru]

Originally Posted by E92Monroy

Having the same issue any tips ? Or did you figure out what was the issue ?

Make sure the belt is properly seated on the lower pulleys. The two times I've put a new belt on my 335i I had to work a little harder to get the belt around the crank pulley more than any of the others. It tends to get hung up.

I would probably suggest starting at the bottom and continuing to pull the belt tight as you work your way up. Idk...it took me like 2 minutes last time using the routing that I posted further up in this thread.

[john_bmw_porsche]

Hi Guys,

I have a 2008 335I with 48K miles.
Recently the original serpentine belt die catostraphically. It was totally shreaded.
I installed a new serpentine belt... It also shreaded in a matter of days.

I figured it was an ancillary component that could be locking up. Over stressing the belt and killing it.

I thoroughly inspected all ancillary components which seemed to rotate smoothly. HOWEVER, during the inspection I found that pieces of the old belt were entangled in the alternator and parts of the belt were behind the power steering pump. My thought was that the old pieces of shreaded belt were getting into the new belt/pulley and kicking off the belt.

I thoroughly inspected the entire front of the engine, pulled off the harmonic balancer, inspected for belt pieces, inspected the main seal and buttoned everything back up... Bought a new belt and installed it.

While the engine bay was still open we started the car and inspected the operation of the belt. Incredibly within a matter of minutes the belt was kicked off the pulleys and was shreaded.... FURTHER INSPECTION found that the power steering pump bolts backed out leaving the air pump non-secured. The mis-alignment of the air pump kicked the belt off the pulleys the subsequent rotation of engine ancillary driven parts killed the.

Lesson learned... IF your car shreads belts. Look at proper attachment and alignment of all components.

I tightened all ancillary drive components, installed another new belt and it runs great.

[Mustafa.e92]

Originally Posted by john_bmw_porsche

Hi Guys,

I have a 2008 335I with 48K miles.
Recently the original serpentine belt die catostraphically. It was totally shreaded.
I installed a new serpentine belt... It also shreaded in a matter of days.

I figured it was an ancillary component that could be locking up. Over stressing the belt and killing it.

I thoroughly inspected all ancillary components which seemed to rotate smoothly. HOWEVER, during the inspection I found that pieces of the old belt were entangled in the alternator and parts of the belt were behind the power steering pump. My thought was that the old pieces of shreaded belt were getting into the new belt/pulley and kicking off the belt.

I thoroughly inspected the entire front of the engine, pulled off the harmonic balancer, inspected for belt pieces, inspected the main seal and buttoned everything back up... Bought a new belt and installed it.

While the engine bay was still open we started the car and inspected the operation of the belt. Incredibly within a matter of minutes the belt was kicked off the pulleys and was shreaded.... FURTHER INSPECTION found that the power steering pump bolts backed out leaving the air pump non-secured. The mis-alignment of the air pump kicked the belt off the pulleys the subsequent rotation of engine ancillary driven parts killed the.

Lesson learned... IF your car shreads belts. Look at proper attachment and alignment of all components.

I tightened all ancillary drive components, installed another new belt and it runs great.

I'd still atleast drain the oil and stick a boroscope through the oil level sensor and check inside the pan