New Belt Tensioner Issues
 

Hey guys, I just bought new tensioner assemblies for both the a/c and main accessories for my 4.6 but I’m having an issue with the tensioners themselves. Admittedly I cheaped out and went the eBay route but I still must be missing something because both assemblies came from different vendors. The issue I am having is that both tensioners will not compress. It’s as if they are frozen or locked in place. Do the tensioners unlock like the timing chain tensioner does?

I’ve searched all through Google and YouTube but found nothing. I pulled the rubber boot up on the a/c tensioner and there’s fluid inside and if I twist it, I hear what sounds like a spring inside but it just will not compress. So did I miss a step or is it just a wild coincidence that two tensioners from two different vendors are shot? Thanks in advance.

Pictures would help.

The tensioner on my n55 motor comes pinned compressed you need to compress the spring a little more to release the spring.

https://www.bimmerworld.com/BMW-1128...ensioner-1.jpg

This is the part I'm referring to, the hydraulic tension strut. It doesn't compress like in the video clip below (3:50 mark)

https://www.youtube.com/watch?v=jn4Yd_OSljM

Probably got so much tension on it that you cannot compress it by hand?

I'm sure it takes a lot of force to compress. How big of breaker bar are you using?

Didn’t use a breaker bar, just a 17mm socket and long handle ratchet… wouldn’t budge but even with that, it felt like I was going to snap a bolt or something. I know it shouldn’t compress easily but this thing really feels like it’s locked or something.

I'm sure not the case but you didn't tighten the locking bolt?

No, I left those two bolts loose… I wanted to compress the damper 3 times as I’ve been seeing online but they wouldn’t budge. I tried compressing it out of the car on the ground with downward leverage and nothing. If I can get access to a bench vise, I’ll try that. Other than that, I don’t know what the issue is unless it really is a weird coincidence that the two dampers are bad even though from two different places. FCP Euro has the main damper available if it comes down to it but the damper for the a/c is 4-6 weeks out :(

It begs me if there is a transport mode or such where turning the end of something unlocks it. Think of how lotion pump bottles come locked until you turn the pump 90°. It's very mysterious and bench vice would be my next thought.

I thought the same exact thing and rotated it while trying to compress, still no go. All I hear is what sounds like a spring binding up when I rotate the damper. Tried to find images of one disassembled to get some insight on how it functions exactly but nothing came up. Tomorrow I’ll see if I can get to a bench vise or something.