Tensioner pulley very loose (video)

Today after starting my car, I got a charge malfunction error and my power steering would not work on my 2007 525i. I looked under the hood and the serpentine belt was hanging. After getting into it, I noticed the tensioner pulley (or at least that's what I assume it is) is very wobbly and loose. However, I can't see a way to get the darn thing off to inspect it or how to tighten it back up. I've searched all over and can't find anything specific to an e60. Any help would be greatly appreciated.

Here's a video:



Also, does anyone know where I can find a serpentine belt diagram for anE60? I've found them for nearly every other model but an E60 for some reason.

That is definitely the belt tensioner. There is a bolt at the center of that belt tensioner assembly (not the center of pulley) to remove the tensioner assembly from timing cover.

Here is the picture showing how the belt is routed.

You video shows the bolt in the center of the spring that is the issue. Since I recently changed mine, what I see as the problem is you are missing the steel washer that goes under the bolt. Basically your hex bolt head is slipping into the shaft. You can look around your bottom pan for the washer or get a new one. There is probably nothing wrong with the tensioner itself.

My guess is the bolt came loose or someone had taken it off before and never properly installed the washer.

Originally Posted by Hogie

You video shows the bolt in the center of the spring that is the issue. Since I recently changed mine, what I see as the problem is you are missing the steel washer that goes under the bolt. Basically your hex bolt head is slipping into the shaft. You can look around your bottom pan for the washer or get a new one. There is probably nothing wrong with the tensioner itself.

My guess is the bolt came loose or someone had taken it off before and never properly installed the washer.

Interesting...you wouldn't happen to have a size or picture that I could work off of to possibly go grab a washer and see what happens?

Also, after re-routing the belt and starting the car, here's what happens to the belt on the tensioner...

Originally Posted by Hogie

You video shows the bolt in the center of the spring that is the issue. Since I recently changed mine, what I see as the problem is you are missing the steel washer that goes under the bolt. Basically your hex bolt head is slipping into the shaft. You can look around your bottom pan for the washer or get a new one. There is probably nothing wrong with the tensioner itself.

My guess is the bolt came loose or someone had taken it off before and never properly installed the washer.

I've replaced belt tensioner on N52. I don't remember removing or installing a washer on the tensioner assembly bolt. See the attached ...

Originally Posted by robertmspeakout

Also, after re-routing the belt and starting the car, here's what happens to the belt on the tensioner...

Remove the belt, try tightening the center bolt on the tensioner and then put back the belt.

The head of the bolt that is supposed to hold the tensioner in place has broken off from the rest of the bolt. You need #5 in this picture.

http://www.realoem.com/bmw/showparts...40&hg=11&fg=18

it's hard to tell from the video what is interfering with you being able to remove the tensioner assembly, but you might have to remove something else or maybe just try rotating the tensioner assembly to find the sweet spot to remove it. Worst case - you have to get a pair of vice grips or bolt extractor onto that bolt to remove that portion of it before you can remove the tensioner.
Inspect the tensioner carefully before reinstalling. i'd say there's a good chance that broken bolt is a symptom of something else, like maybe the bearing in the pulley seizing? Also, I think that's an aluminum bolt, which should never be reused for this exact reason - it weakens. To your knowledge, has that tenioner ever been removed and reinstalled?

Originally Posted by vavet5308

The head of the bolt that is supposed to hold the tensioner in place has broken off from the rest of the bolt. You need #5 in this picture.

http://www.realoem.com/bmw/showparts...40&hg=11&fg=18

it's hard to tell from the video what is interfering with you being able to remove the tensioner assembly, but you might have to remove something else or maybe just try rotating the tensioner assembly to find the sweet spot to remove it. Worst case - you have to get a pair of vice grips or bolt extractor onto that bolt to remove that portion of it before you can remove the tensioner.
Inspect the tensioner carefully before reinstalling. i'd say there's a good chance that broken bolt is a symptom of something else, like maybe the bearing in the pulley seizing? Also, I think that's an aluminum bolt, which should never be reused for this exact reason - it weakens. To your knowledge, has that tenioner ever been removed and reinstalled?

To my knowledge the tensioner has never been removed.

[Update] I was actually able to tap a small flat head into a sharp corner of what was left over on the bolt and get it to turn enough to get some needle nose on them. I got it off. However, I was able to more fully see the small crease that is in the top right of the tensioner caused by the belt coming from the alternator to the right of it. Surely this is too close for comfort???

After further investigation, the bolt has in fact sheared off. There is not enough of the bolt left over to place any grip on. I'm not sure how to proceed to get the tensioner off.

You could use a Dremel to cut a slot in the bolt shank. If you have to cut through the tensioner too, no biggie - replacements probably aren't too pricey.

If its a soft metal a easyout reverse bit and penetrating oil might work.

With a new tensioner the new bolt and washer come with it. You can not run your engine without the tensioner.

Order one from www.autohausAZ.com

It will come with the new bolt and washer already installed. The other posts are correct, that the bolt head has sheared off, therefore lost the washer.