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BMW E46 M54 Idler, Tensioner and Water Pump Pulley Replacement PICTORIAL & VIDEO DIY!

If your Pulleys are squealing under the hood every time you start your car then DIY them out of there now or they will fail on you and leave you stranded road side!

Here is an older video from last November of what my pulleys sound like months before they inevitably and eventually failed. At the time I shot this video I didn't understand what these sounds were but now I do and I will never ever ever forget them.


I did all my Pulleys in less than an hour. Parts all cost under $100 which was almost equal to what I paid just to tow my car off the highway when the pulleys finally gave way and excused themselves from my Belt Drive as I was cruising down the highway.

I also replaced my belts at the same time and now my engine bay is quiet, the car accelerates way better and my MPGs shot right back up to low 30s highway and mid 20s city.

Said and done the hardest part of the DIY was putting the fan back on the car.

The tools required are:

-Fan Clutch Tools if your car is an automatic/steptronic - costs about $30 and up on ebay
-Breaker bar/Ratchet Handle set about 8 inches and up (the bolts aren't super tight but the longer handle makes removal easier)
-5/8" or 13mm socket, 10mm socket and T50 Torx head-to de-tension the AC Belt Tension Pulley

Tools not required but you can use if you have them:

-Ratchet socket extension 3 or 5 inch to reach the Tension Pulley lower mount bolt in removal of the tensioner pulley

-Torque Wrench (I didn't use one, but you can if you want)

PART ONE: To remove the belts and fan clutch see my DIY here:

Pictorial DIY: BMW E46 Fan Clutch Removal & Engine Belts Change For Automatic Cars - E46Fanatics

PART TWO: For the Pulleys here are the Video DIY Guides:

PART THREE: Here is a Pictorial Reference describing key points in the process:

ImageShack Album - 15 images

PART FOUR: Here is the original thread of the incident and the reason I should have changed my pulleys FYI

So since I been back from vacation (my car was parked up in the sun for a week whiles I was away) my engine bay has been making the cold engine monkey screeching/bird chirping sounds with the cold engine acceleration whistle. It was getting louder and I've been just turning the radio up and ignoring it.

My car just hit 56,000 miles on the odometer and I've been scheduling myself for a full coolant over haul at the end of the summer and I figured the sounds meant I needed new pulleys eventually. I planned to replace them at that time.

Today I got out work early, got home early off the Metro North Train literally ran home to my car as I had my evening planned out for dinner, movies and drinks in the city.

It was 83 degrees when I set out from Westchester, hitting speeds of 80 and 90 mph down the Saw Mill Pkwy South and about 17 miles down the highway (I was now on the Thruway 87 South aka the Major Deegan) my red Check Battery light came on. I knew right away the battery and/or alternator needed replacing in a couple of hours so I didn't panic. I really should have just exited the Major Deegan Hwy then but I've dealt with the check battery light on my old BMW 318i a few summers back and figured I had a couple of hours to a day to get a new battery and the alternator checked out.

A few seconds later my Engine Temp Needle literally raced over to the RED!!!

Knowing what I know about the e46 cooling system failure I pulled over immediately and realized my power steering was gone and my AC went hot.

As I got out and walked towards the front of the car I could only face palm myself as I expected to see coolant fluid all over the road, smoke and fire eating thru my nose panel grills and bits of plastic poking thru the metal hood.

I popped the hood and to my surprise everything looked calm until I noticed the fan belt was M.I.A.

I got my fan removal tool which luckily I've been forgetting to remove out my trunk and took the fan off to see this nonsense...

Idler Pulley M.I.A (as in exploded off the bolt and long gone)

YouTube - BMW 330i E46 Idler Pulley Fail! What The Aftermath Looks Like Under The Hood!

The Water Pump/Fan Pulley also cracked on me as I removed the fan...

My car insurance comes with unlimited free tow service. Sadly, the Major Deegan 87 has heavy Police Dept. tow restrictions so ONLY one Tow Company can tow your car off the highway where I broke down (even the exit ramp off the highway where I was is restricted)...

So I waited from 4:17pm to 6:23pm for just the Police to show up. Then I waited in the same spot from 6:30pm to around 8:00pm for their Tow service to show up...

And what sucks ass is these numnuts only Tow off the highway and they charge you for that! Guess what they charged to literally tow my car 20 feet or less off the exit ramp from where I broke down to the perpendicular street.

$70 plus tax! Worse the Police stay in the background observing you the entire time so you can't argue with their Tow Driver. You just gotta pay them and shut up.

Now I had to call back my Insurance Company for another Tow Truck and I literally waited until 10:00 pm for them to show up and they tow you to their shop.

What a Crazy A$$ Day!
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