sovietmusclr

I own a 2016 RLX tech fwd and ever since purchasing it 7 months ago I've been noticing a slight rattle/clunking coming from front passenger side wheel area. I had the shocks replaced under warranty twice to no avail. I saw some other owners on here have experienced similar issues. It seems as though the noise is "characteristic" of the shock absorbers. I believe Acura is aware of this issue which is why the shocks were changed in 2016 compared to vehicles made in 2014-2015. In 2018, I noticed the shock and spring were changed yet again yet all the other suspension components stayed the same. My plan is to replace the front shocks and springs with the ones from 2018 RLX, but prior to doing so I was hoping to hear people's feedback on the ride quality and if they experience any rattle in 2018-2020 RLX at speeds 20-40 mph. In my car, the noise is more detectable on cold winter days at speeds ~20 mph when riding over uneven surfaces.

mrgold35

I purchased an used 18 RLX hybrid in Dec/19 with 7200 miles (+10,200 miles now). I've haven't noticed any rattle/clunking from the suspension from any corner. The suspension for the +18 RLX hybrid is on the softer side with more body roll and bounce over bumps. My 19 MDX hybrid with the IDS in Sport mode has a much more noticeable sporty and firmer ride with electronic dampers I prefer more. Don't know how firm or soft the ride is on your 16 RLX; but, the +18 RLX ride isn't as good for spirited driving for being a 377hp sport sedan. You might be trading one problems for another with the +18 OEM set-up.

I prefer a sporty ride and was leaning toward getting BC Racing coil overs; but, the webside only list for the 14-16 RLX: https://www.bcracing-na.com/products...1-6e2064ea40ac

sovietmusclr

The 2016 RLX is fairly firm for lux car this size. I owned an 05 TL with A-SPEC suspension and I think the rides are comparable except the TL didn't didn't rattle. I live in the Northeast - greater Boston, area and our roads are far from perfect. That is why I hear the rattling fairly frequently especially while the shocks are cold. If I lived in an area with better roads, I would probably not bother with the shocks. I would be happy with a slightly softer ride especially if the occasional clunking went away. I am also considering downgrading my 19" wheels to 18" when the tires wear out. Hopefully that extra 1/2" of sidewall would help also.

mrgold35

I haven't had a chance to test drive the 14-16 RLX because they are nearly impossible to find in New Mexico with only one Acura dealership in the state. I've heard those model years (especially the 14) have a more sporty/firmer ride. I'm used to a firmer rides of my 06 TSX (A-Spec suspension+Progress RSB), 08 RDX (Eibach lowering springs+Progress RSB), 11 MDX Adv set to Sport with magnetic struts/shocks+larger OEM front/rear stabilizer bars, and 19 MDX Hybrid with electronic dampers. My 18 RLX hybrid is the softest suspension and doesn't feel as secure and planted in the corners compared to my previous Acuras.

You might be able to find a fwd and/or hybrid +18 RLX to test drive and see how it compares to your 16 RLX before ordering the +18 suspension. I'm assuming the +18 RLX fwd and hybrid use the same suspension part number. Not an expert on the +18 RLX MMC changes; but, it looks mostly external cosmetic changes (I think the +18 RLX hybrid got a smaller battery pack for a touch more trunk space).

Triaque

mrgold

The reason Honda reduced the size of the battery in the 2018+ RLX SH SHAWD was not for space. The tiny pocket of space above the battery pack provides no practical usable space in the trunk.

Honda/Acura spin on this change was a marketing ploy. They reduced the size of the battery to reduce the cost of one of the costliest part streams during manufacturing of this vehicle line. Honda corporate knew they were going to struggle selling these for a profit so they did this to sell them at the new price point that you see now. With other cost adjustments which included NOT upgrading the telematics......they have been able to sell SH SHAWDs at average prices of around 51000-53000 USD depending on dealer location.

sovietmusclr

I plan to test drive a 2018 RLX fwd when this Corona scare passes before I order the parts. What bothers me is that I did not notice the rattle in my car when I test drove it partially because I did not look for it, but also because the test drive was mainly on a smooth highway. That's why I posted the question here to hear from people who've driven a few thousand miles. I compiled a list of shock part numbers for different RLX trims from 2015-2020. I found at least 5 different part numbers when comparing the front right shocks (spring part numbers differ also). Here are the P/N for front right shocks:
2014-2015 RLX tech fwd => 51611-TY2-A01
2016-2017 RLX tech fwd => 51611-TY2-A11 (mine)
2016-2017 RLX tech hyb => 51611-TY3-J01
2018-2020 RLX tech fwd => 51611-TY2-A32
2018-2020 RLX tech hyb => 51611-TY3-A32 (yours)
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​​​​​​Most likely I would use the shocks and springs from 2018-2020 RLX tech fwd. On a side note: I loved the A-Spec suspension in my TL. To me that was near an optimal balance of comfort and sportiness without any suspension noises. Miss that car :-(

mrgold35

The tiny trunk and smaller gas tank does make it harder for longer road trips for more than 2 in the RLX Hybrid with gas stop 4-5 hours in-between out west. The little shelf above the trunk mounted battery pack does have a mini cargo net and I store my re-usable grocery bags under there.

KenRLX

I have been there and done that damper swap thingy before on a '14. The dealer would not agree to swap to newer dampers, so I just bought my own.
What I got from Acura parts department was an unmarked set of dampers that could have been for/from ANY RLX version and year.
And ,, they were the worst rattlers of all the ones I had on that 14.
If you buy new dampers, refuse delivery if they are not labelled with the proper part number that you ordered. Not the paperwork, but the label acutally on the damper. If you did get the dampers already, let us know in the forum how they worked.

Meanwhile, do a very careful check of ball joints and, particularly the sway bar links.

But I do agree about your slow speed observations. The '14 would clunk in a slightly wavy but otherwise smooth parking lot just from the slight differences in up/down wheel travel at 5-10mph.

I fixed my '14 PAWS damper issue by getting a '19 RLX SH. (That is a night and day difference!)

I strongly believe that there is also something wrong far deeper in the chassis than the dampers causing the rattles on specific RLX's.

sovietmusclr

Did the rattling go away entirely once you replaced the dampers or do you still notice something which is why you mentioned the chassis? Also, did you notice the rattling on both sides ? I feel like I hear it more from the passenger side.

KenRLX

The rattling NEVER went away, despite going through 12 front dampers (6 sets). (Including swaps under TSB and the set I bought on my own) The rattle occured on both sides.
Some were 'better' than others, but still light-years away from any other make of car on the market.

Acura acknowledged that the main reason for the 'rattle' is the design of the damper and even had a video on the acura web site explaining the 'rattle'. Yet they seemed to never sway from that basic design approach with the TSB updates because the marketing blurb for the RLX claimed 'adaptive dampers'. The complex set of valves in the damper (also called shim stacks) would bind up, then the pressure would suddenly release (POP!) with damper rod movement. A number of SAE technical papers over the years have described the 'rattle' effect of poorly designed damper valving.
IMO, Acura tried to get 'too fancy' with the damper design and ask a passive hydraulic system to do things that are impossible. Acura should have either done the electronic controlled damper approach or used a more conventional design.

But, after 12 rattletrap dampers, I do suspect something about the chassis itself. Some owners report no rattles, others major rattles. So I suspect something about the particular build of the chassis for each car may also induce rattles in addition to the damper effect.
Just in case, closely inspect the ball joints!

I test drove the '19 SH particuarly listening for rattles and heard none. It remains a quiet ride. I have not yet heard on this forum a complaint about damper rattle on an SH.

I stress again, if you buy dampers, they must have the part number on the damper itself! Otherwise you might be buying some junk leftovers from 2013 that were stuck in a warehouse. And you'll never sort out if the rattle is damper induced or from some other cause.

sovietmusclr

Thank you for the insight! I will update this thread once I do the swap. If I understood you correctly, my best bet would be to use 2019 RLX Hybrid SH-AWD shocks with matching springs and to make sure the ball joints are in good ok. In my case the noise is mostly on the right side so it could be a ball joint. I've gone through 3 sets of shocks on that side now.

sovietmusclr

​​​​​​Are you referring to the ball joint that's part of the upper control arm (#5) in the diagram above? Is that a common issue ?

KenRLX

I am referring to any/all iball joints n that diagram, and including control arm bushings. - As well as the ball joints on the sway bar links
Any one of those could be confused with a damper rattle.

I agree that is is a reasonable approach to get vintage 2019/2020 SH dampers and give it a try. (As that is what i tried to do). But beware the Acura parts system - a dusty damper lingering in the warehouse made in 2013 for a PAWS will indeed 'fit' a 2019 SH and might be deemed an acceptable replacement for the 2019 part number by Acura and blindly sold as 'identical'