# E70 35d Fluidampr Replacement - Initial Experience



## SPL15 (Feb 3, 2019)

Noticed the OEM crankshaft harmonic balancer (guessing original) was looking pretty worn when I did the water pump, thermostat, trans thermostat, tensioner pulley, & idler pulley about a month ago. Stock torsional balancer had countless small fissures / cracks on the "rubber" where it met the center hub & the outer ring, also a lot of reciprocating back & forth movement on the tensioner pulley mechanism regardless of whether the engine was cold or hot... Probably could have gone a while before an "ultimate result" sort of failure would occur; however, in this state, its dampening characteristics are no doubt altered from factory spec... A poorly operating harmonic balancer is a great way to accelerate engine bearing wear, even if the balancer has not yet catastrophically failed in a manner that is noticeable...

Finally got around to replacing the OEM harmonic balancer with a Fluidampr from AARod Corp, along w/ the included INA clutched alternator pulley after putting things off for the past few weeks... So far, after only 50 miles or so, am impressed w/ the objectively smoother engine idle, as well as seeming elimination of the "clattery" diesel truck sound that I would sporadically get when mid-hard throttle between 1.5K - 3.0K. Full throttle accelerating on an onramp doesn't feel a whole lot different, but it does seem less noisy (confirmation bias will of course be a factor for my observations).

Upon initial startup, idler pulley arm was reciprocating back & forth at about the same magnitude as w/ the worn out OEM crankshaft balancer, even after several minutes at idle; however, this quickly settled down after a short "round the block" drive, where movement of the idler pulley arm was FAR less than I've ever seen it, to where it's hardly moving now... This could of course be a function of the new clutched alternator pulley "wearing in" a bit, as well as the engine now having a properly functioning harmonic balancer, where similar results could possibly be attained w/ either just a clutched alternator pulley, and / or a new OEM crankshaft balancer...

The big thing I noticed was how much less the engine shakes at idle when viewing it w/ the hood open. It wasn't bad at all before, felt perfectly fine when inside the cabin with no noticeable issues at all; however, it was noticeable that the engine was vibrating a bit with the hood open & watching things oscillate (the dynamically controlled engine mounts are definitely doing their job & work awesome)... After installation of the Fluidamper, the engine nearly idles as smooth & silky as my E46 325i, w/ no visibly perceptible shaking of the driver's side air-intake tube from the air-box anymore... No rattling from it, no visible shaking of the engine... That was impressive; however, the same result could possibly be attained from a new OEM balancer that is actually dampening torsional resonance...

Overall, quite happy w/ the Fluidampr replacement that costs similar to the OEM unit, but should last far longer than I plan to own my E70 35d / far longer than my current engine will lasts, as well as being suitable for planned "off-road" modifications in the coming future... Whether similar results could be had if I'd simply replaced the worn out balancer with a brand new OEM unit, I will never know & can't say; however, the fact that I've noticed such a tangible difference after replacing my worn out unit, should cause you to examine your harmonic balancer for ANY amount of fracturing / cracking / wear, & replace it preemptively well BEFORE it catastrophically fails.


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## Doug Huffman (Apr 25, 2015)

There have been few reports of catastrophic failure of crankshaft torsion vibration dampers despite nearly every production ICE having one. Ours is NOT a ***8216;balancer***8217;, not having counterweights.

The elastomer is fragile to fuel and lubricant contamination and low temperature embrittlement, below its Glass Transition Temperature *Tg*.

About your shaking, please note that we have variably tuned motormounts.



NewTIS said:


> Function: The pressure converter connects the engine mounts to the vacuum supply. When the DDE control unit activates the pressure converter, the pressure converter responds by applying vacuum to the engine mounts.
> 
> The engine mounts are switched to their soft setting at:
> 
> ...


https://www.newtis.info/tisv2/a/en/...esel-electronics-dde7/engine-mounting/X418s9P


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## jfxogara (Oct 26, 2012)

Great writeup thanks.


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## n1das (Jul 22, 2013)

Are we talking about a damper (i.e., shock absorber) or a dampener as in something used to moisten or get something wet?


Sent from my XP8800 using Tapatalk


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## ard (Jul 1, 2009)

n1das said:


> Are we talking about a damper (i.e., shock absorber) or a dampener as in something used to moisten or get something wet?
> 
> Sent from my XP8800 using Tapatalk


Actually 'dampener' is a proper use ....

:angel:


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## Nyc Dito (Jun 11, 2015)

Thanks for the review. I have the Fluidampr on my "to do" list and will have my Indy take a look tomorrow when they get my car into the shop.

Thanks again


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## robnitro (Aug 3, 2016)

Sorry but I think most of the smoothness comes from the clutched alternator pulley.
Without that, they had issues with the fluidampr, which I think was not fully tested and engineered for our specific engine. In other words, the fluid dampr alone was not as good as the stock damper UNTIL they added the clutched pulley!?! What does that make you think? Hmmm

I might get the clutched pulley to use with the stock damper and see if it changes anything.

What's funny is that my vw TDI had a clutched alternator pulley stock. Yet the "higher end" BMW does not... Pfft


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## Thecastle (Feb 5, 2016)

I've had problems with idle quality on mine as well. Mine has never idled as well as it did with the stock harmonic balancer. I've replaced my Fluid damper with a second damper and it Worked better.


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## SPL15 (Feb 3, 2019)

The stock damper is a viscous type as well, so I'm more leaning towards the clutched pulley and / or failed stock damper being the cause of my slight vibration at idle, as well as the rattling noise at certain RPM's under minor to moderate load.

The elastomer portion of the stock damper only supports the pulley portion of the damper to decouple engine torsional vibration from the driven accessories; the viscous portion of the damper is directly coupled to the hub that mounts to the crankshaft end. The stock damper is a viscous "Fluid" damper (likely silicone as well).

On my failed OEM damper, the elastomer portion had lots of small fissures & cracks, further inspection showed leaking fluid out of the viscous disc portion at what look to be plugged fill ports (Guessing they're filled via a submerged vacuum fill & then plugged). My guess is that the damaged elastomer portion wasn't adequately supporting the pulley section, where it was ratting against the fixed viscous damper disc under some conditions. The clearance between the Viscous disc & the pulley section is quite small, wouldn't take a lot to cause these two things contact if the elastomer is severely worn.

One issue I have noticed is that at warm idle, I can just barely perceive a tiny bit of engine vibration thru the steering wheel, where it doesn't feel as silky smooth compared to before the swap, but only at idle w/ zero throttle input. This would make sense, as the pulley on the aftermarket Fluiddmpr branded viscous torsional damper is directly coupled to the crankshaft, without the elastomer decoupling element that the stock unit has. The clutched alternator pulley only helps to decouple crankshaft vibration from the device it is mounted on. 

Idle quality, at least on my X5, is alarmingly quiet & smooth, even on a cold engine, with things approaching the level of my well maintained E46 at warm idle. The Fluiddampr does work, & I'm still overall happy w/ the purchase & performance; however, I'd certainly not fault someone for simply going with the stock OE or OEM unit that can be had for around the same price.


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