[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.

[F32Fleet]

This is really good info. The job isn't difficult per se but it does require one or two, depending on what you have, torque wrenches if you want to replace the tensioner and idler pulley while you're in there.

[F87source]

Originally Posted by F32Fleet

This is really good info. The job isn't difficult per se but it does require one or two, depending on what you have, torque wrenches if you want to replace the tensioner and idler pulley while you're in there.

Thanks.


Generally a 3/8" drive torque wrench can do the job if it's in the range of 10-80 ftlbs.

[BashShah]

F87Source, where in Canada are you located? which city.
PS: Love your posts.

[F87source]

Originally Posted by BashShah

F87Source, where in Canada are you located? which city.
PS: Love your posts.

Thanks for the kind words.

I prefer not to say lol, but if you need anything pm me.