[F87source]

Introduction:

In this short post we will briefly discuss how a serpentine belt wears on these modern day bmw engines, what happens when a belt fails, and the importance of routine belt wear checks and preventative maintenance. Before we begin I must thank ECS tuning/Turner motorsports for giving me a partial discount on the products that I will be using in this review, however I will be as unbiased as possible despite that.

Disclaimer:

Any technical advice, installation instruction, or product installation is done so at your own risk I will not be responsible for personal injuries, injuries to others or any living being(s), or any damage to your car, or any property damage.


Credits:

Images and videos used in this review are all property of their rightful owners as credited below each image, I am just using them for the purpose of this review but if you (the owner of the image) would like them removed please let me know via pm. Otherwise thanks to the owners (I made sure to credit your online name and link where I found the photo) of the photos, without you this review would be so much more bland.


How a modern day continental belt wears:

So for those of you that do not know, these modern day continental serpentine belts that bmw uses are made from a new compound that no longer cracks when these belts age. This means that a visual inspection for belt wear no longer works to judge belt life, instead these belts wear thinner as they are used - just like car tires. This means you must measure rib height to determine belt life, and even rib spacing (due to wear from the grooves on the pulley and potential stretching). This measurement can be done with a cheap tool that continental makes called the contitech belt wear tester tool (more on this later). So if you hear people say “this belt looks good” referring to it being relatively clean and free of cracks and they did not use a continental belt wear tester - their judgement is inaccurate and doesn’t signify belt health at all.


Continental Belt Wear Tester Images:


Credit: F87source


Credit: F87source

Credit: F87source


Credit: F87source


What happens when a serpentine belt fails:

When a serpentine belt fails it can wrap itself around the harmonic dampener which then in turns sucks the belt behind it and forces it past the front crank seal. From there the timing chain sprocket and oil pump sprocket chews up the serpentine belt and some of that belt material gets carried up into the head via the timing chain. The parts that do not get pulled up into the head gets fed into the oil pan where it can clog up the oil pump pick up causing catastrophic engine damage and if the engine hasn’t failed yet a costly repair would be required, more on this in this thread: https://f87.bimmerpost.com/forums/sh....php?t=1807187 where I discuss this issue indepth and also discuss a solution to permanently prevent any engine damage from belt failures. But this is a quick summary on what happens when a belt fails.


How to check belt wear and when to replace these belts:

So how do we prevent serpentine belt failures from occurring? Well the first method to tackle the belt failing is commonly checking the belt for wear (this will not eliminate all belt failures caused by other issues as discussed in this thread: https://f87.bimmerpost.com/forums/sh....php?t=1807187). This can be accomplished using the tool that continental has created called the contitech belt wear tester: https://www.continental-engineparts....elt-Wear-Gauge

This tool as shown in the above video allows the user to check the depth of the grooves and width of the rib spacing, allowing for an accurate determination of when to replace your belt because these belts wear thinner and will not show its age by cracking as mentioned earlier. With this tool you can always keep an eye on your belt’s wear and replace it before it breaks and potentially causes engine failure.

Now this is where ECS tuning/Turner motorsports comes in clutch, I have looked everywhere for these testers and no one sells them except for ECS tuning/Turner motorsports, so big props to these guys for stocking all the cool things that no one else does. So if you are looking for this handy little tool here is the link to buy it: https://www.turnermotorsport.com/p-3...t-wear-tester/ it is really cheap so I highly recommend those who maintain their cars by themselve to purchase one.


Before we wrap up this review I would like to also quickly summarize when to replace your serpentine belt:

1) When the grooves become to shallow as indicated by the belt wear tester

2)When the rib spacing becomes too wide that the teeth of the belt wear tester no longer fit snuggly

3) When the belt is over 5-6 years old, now this is the recommendation I was given when speaking to continental and not many people know about this but belts can degrade over time due to ozone damage (ozone degrades rubber) and constant heat cycling. So make sure you replace your belts if they pass this time frame even if the tester shows they are fine, $30 for a new belt is much cheaper than the hundreds or thousands of dollars in parts and labour to repair your engine.

Overall I recommend bmw owners spare a bit of time and money to do the proper preventative maintenance to take care of your car, otherwise the consequences of not doing so can cost many times more.

[F87source]

Reserved for future posts.

[jefe2000]

The OP pointed my attention to this belt wear tester on another thread. It looks excellent, especially for owners DIY’ing the maintenance.

Unfortunately it looks like Turner has stopped selling this tester. The URL to the page at Turner for the tester no longer works. It’s too bad: I’d love pick up one of these testers.

If anyone finds another way to purchase one of these belt wear testers, I’d love to know!

[F87source]

Originally Posted by jefe2000

The OP pointed my attention to this belt wear tester on another thread. It looks excellent, especially for owners DIY’ing the maintenance.

Unfortunately it looks like Turner has stopped selling this tester. The URL to the page at Turner for the tester no longer works. It’s too bad: I’d love pick up one of these testers.

If anyone finds another way to purchase one of these belt wear testers, I’d love to know!

Man I'm starting to wish I got more than 1 lol, but I am very glad that I was able to obtain atleast one of them - and the funny thing is at the time when they were readily available no one thought this was a good purchase despite it literally being $1, so in hindsight everyone should have bought one lol. Yes they're very well built, but I'm always worried about if it's going to last a lifetime - especially since all 3 of my cars are running continental belts. I'm going to have to take super duper good care of it now.

[jefe2000]

I might have a bead on an alternate source for this belt wear gauge. I’ll let ya know if it pans out!

[jefe2000]

I was able to source a Continental belt wear tester for myself from CRP Industries (located in the US state of New Jersey). It arrived in the mail sometime over the past few weeks — I was out of the country for most of July, so I only just received it.

I found a tip on how to obtain a wear tester in this HumbleMechanic YouTube video:
https://youtu.be/Clv2ZlS3hB0

See the video description for details. I don’t want to deny HumbleMechanic the views or likes on his video, so instead of copying/pasting the details here, I recommend heading over to the YouTube video page and reading the video description.

CRP Industries sent me one Continental belt wear tester at no charge (see attached photos). I’ve sent follow-up questions to CRP Industries about whether more are available for purchase or whether I can send friends/family to them to obtain their own belt wear testers. If I’m able to purchase some extra ones and CRP Industries won’t provide them to non-USA residents, maybe I can pass them along to fellow forum members for the cost of the device plus shipping. I’ll update here when I hear back from CRP Industries. And I think the OP is in Canada, so I’d be interested to know if he could source a wear tester from CRP Industries.

[F87source]

Originally Posted by jefe2000

I was able to source a Continental belt wear tester for myself from CRP Industries (located in the US state of New Jersey). It arrived in the mail sometime over the past few weeks — I was out of the country for most of July, so I only just received it.

I found a tip on how to obtain a wear tester in this HumbleMechanic YouTube video:
https://youtu.be/Clv2ZlS3hB0

See the video description for details. I don’t want to deny HumbleMechanic the views or likes on his video, so instead of copying/paying the details here, I recommend heading over to the YouTube video page and reading the video description.

CRP Industries sent me one Continental belt wear tester at no charge (see attached photos). I’ve sent follow-up questions to CRP Industries about whether more are available for purchase or whether I can send friends/family to them to obtain their own belt wear testers. If I’m able to purchase some extra ones and CRP Industries won’t provide them to non-USA residents, maybe I can pass them along to fellow forum members for the cost of the device plus shipping. I’ll update here when I hear back from CRP Industries. And I think the OP is in Canada, so I’d be interested to know if he could source a wear tester from CRP Industries.

Good stuff man!

[maxcbrdriver]

Great catch, request made! Let's hope that they have a few left.

[jefe2000]

Originally Posted by jefe2000

CRP Industries sent me one Continental belt wear tester at no charge (see attached photos). I’ve sent follow-up questions to CRP Industries about whether more are available for purchase or whether I can send friends/family to them to obtain their own belt wear testers.

I heard back from the CRP Industries marketing rep. They aren’t currently set up to process purchases of the Continental belt wear testers they have on hand. They’re happy to provide a free one to anyone who asks, though. Just follow the instructions in the video description on the HumbleMechanic YouTube video in the post above.

[maxcbrdriver]

Just got mine in. Very cool giveaway from CRP.

[Kevin_The_Clean1]

This is awesome & thank you for preventing the N55 in my 2011 E90 335i from going south (with this awesome belt checking tool)...

[jefe2000]

Originally Posted by F87source

3) When the belt is over 5-6 years old, now this is the recommendation I was given when speaking to continental and not many people know about this but belts can degrade over time due to ozone damage (ozone degrades rubber) and constant heat cycling. So make sure you replace your belts if they pass this time frame even if the tester shows they are fine, $30 for a new belt is much cheaper than the hundreds or thousands of dollars in parts and labour to repair your engine.

The belt wear tester has been great for giving me peace of mind that the belt is wearing well on my M2. The car is 5 years old this year and on the original belt. So, even though the belt is measuring fine on the wear tester, I think it's time to preemptively replace the belt due to age.

I'm planning to replace only the belt. My car has only 39,500 mi (~63,500 km) — it seems far too early to replace the tensioner and idler pulley. Yet most belt replacement procedures also include replacing the tensioner and idler pulley.

Am I off the mark in planning to replace only the belt now and the tensioner and idler pulley ~20,000 mi (~32,000 km) down the road?

[F87source]

Originally Posted by jefe2000

The belt wear tester has been great for giving me peace of mind that the belt is wearing well on my M2. The car is 5 years old this year and on the original belt. So, even though the belt is measuring fine on the wear tester, I think it's time to preemptively replace the belt due to age.

I'm planning to replace only the belt. My car has only 39,500 mi (~63,500 km) — it seems far too early to replace the tensioner and idler pulley. Yet most belt replacement procedures also include replacing the tensioner and idler pulley.

Am I off the mark in planning to replace only the belt now and the tensioner and idler pulley ~20,000 mi (~32,000 km) down the road?

You can just replace the belt alone, and keep using the tensioner and pully until there are issues. The tensioner will start to wobble alot when it's wearing out (and do the things that kll describe for that pulley) and the pulley squeals, doesn't spin smoothly (binds), and or wobbles. So if your tensioner and pulley doesn't do those things you're fine. Mileage shouldn't really matter too too much for these parts unless you want to replace them preemptively.

If you reuse a belt down the line make sure you mark direction of rotation and reinstall in the same direction. These belts will wear a certain way so that's why this is important.

[MooMooM2]

the only reason I would just replace everything is because of the work you have to do to replace belt, while you are there kind of thing even though it will be a bit more work (one of the idler pulleys needs the oil lines to be removed (unless you have a T55 that is skinny enough to get there, I know some have gotten it to work but then I don't think there will be a torque wrench thin enough to get int here so best way is to remove the oil lines in front). That said I am also into just replacing stuff that is needed, specially with relatively low miles (even though my idler pulley was making noise and I just replaced it at 32k, I shoulda have replaced the belt while I was there but was cold).

I wish I had one of these measurers handy to at least measure the belt while I had access to it. About to go and try to find one

[jefe2000]

Originally Posted by MooMooM2

the only reason I would just replace everything is because of the work you have to do to replace belt, while you are there kind of thing even though it will be a bit more work (one of the idler pulleys needs the oil lines to be removed (unless you have a T55 that is skinny enough to get there, I know some have gotten it to work but then I don't think there will be a torque wrench thin enough to get int here so best way is to remove the oil lines in front).

I’m running an M2 LCI with the N55 motor and 6MT. So the belt and pulley area is pretty free and clear of obstruction compared to the cars with the S55 motor. See attached image of my engine bay. For me, I think it’ll be OK to get in there now just for the belt and again later on for pulleys and tensioners.

Originally Posted by MooMooM2

I wish I had one of these measurers handy to at least measure the belt while I had access to it. About to go and try to find one

It’s a great tool! Best of luck on snagging one.

[MooMooM2]

Originally Posted by jefe2000

I’m running an M2 LCI with the N55 motor and 6MT. So the belt and pulley area is pretty free and clear of obstruction compared to the cars with the S55 motor. See attached image of my engine bay. For me, I think it’ll be OK to get in there now just for the belt and again later on for pulleys and tensioners.



It’s a great tool! Best of luck on snagging one.

thank you, I messaged to see if they have any left.


Oh N55, look at all that nice space

[F87source]

Originally Posted by MooMooM2

the only reason I would just replace everything is because of the work you have to do to replace belt, while you are there kind of thing even though it will be a bit more work (one of the idler pulleys needs the oil lines to be removed (unless you have a T55 that is skinny enough to get there, I know some have gotten it to work but then I don't think there will be a torque wrench thin enough to get int here so best way is to remove the oil lines in front). That said I am also into just replacing stuff that is needed, specially with relatively low miles (even though my idler pulley was making noise and I just replaced it at 32k, I shoulda have replaced the belt while I was there but was cold).

I wish I had one of these measurers handy to at least measure the belt while I had access to it. About to go and try to find one

Also remember if you have an s55 you have 2 belts to replace (one for the waterpump, and one for the alternator and ac). I heard this makes it a PITA, especially since you guys have so much crap down there in the way. The n55 is alot simpler, and the N20 is even simpler yet (in terms of belt replacement).

[MooMooM2]

Originally Posted by F87source

Also remember if you have an s55 you have 2 belts to replace (one for the waterpump, and one for the alternator and ac). I heard this makes it a PITA, especially since you guys have so much crap down there in the way. The n55 is alot simpler, and the N20 is even simpler yet (in terms of belt replacement).

Yes, in order to remove the alternator/ac you need to remove the other one so it becomes a more annoying job. And yeah its very tight in there, its doable though but I don’t want to know what a shop charges because they will probably drop the fan to get better accesss.