Just thought I would ask if anyone has had any noise from the rear of their cars, and no I don't mean the exhaust. :-) To explain, when I accelerate and particularly at no great rate, I get a single knock noise from the rear which often also occurs when I decelerate from lowish speed. Additionally, I occasionally hear the same knock when I ride over a rough surface. The dealer has had the car twice and has only been able to confirm it is not the cross brace under the rear seat but can't tell me from where the noise originates, albeit they cannot find anything wrong anywhere.
My son called in yesterday and kindly (given his size) sat in the back while I generated the knock at will. He could feel the knock through the trim of the car and he too believes it is from the rear on the right side of the car i.e. your nearside. We took the wheel off but could not find anything amiss, and all bolts seem to be tight but as some of you may know the suspension/drive train is, shall we say, a bit involved so our research was not thorough.

Any clues or suggestions most welcome before I take it to a different dealer.

Thanks in advance.

 

i recall reading of a noise like that which was some loose bolt under the rear seat or something. sorry i can't be more specific, but it's on here somewhere.

 

Thanks Bit and, yes, that was a suggestion I passed onto my dealer. They are convinced that is not the problem but can't offer any other suggestion. I'll take it to another dealer and ask them to investigate, and perhaps fresh eyes/ears will locate the sound source. Personally and given my son's observations, I think it is probably a suspension problem but for a car that's only done 11400 miles I fail to understand why that should be the case.
Will update once it has been in again, 3rd time lucky and all that.

 

^^^^Look at this thread, probably start with Post #19:

https://www.clublexus.com/forums/lc-model-2018-present/862246-slight-rattle-sound.html

 

Many thanks "sickpuppy" and funny enough I was wondering whether it might be the strut that was causing/contributing to the problem. I'll ask the "to be appointed dealer" to consider this as a possibility and I'll let you know what they may or may not find. Again many thanks for the post, much appreciated.

 

i just read that whole thread before seeing your post here.

seems those issues were all related to 2018 year cars and perhaps lexus has fixed most if not all those now.

 

^^^^Most of the posts to that thread were made in 2018 with only a few spilling over to 2019 and 2020

 

I have had one--but my car is a convertible and it was related to the package tray so I am not sure if it applies here?

 

What is a package tray? I am asking because i have a convertible as well and sometimes I hear a soft knock usually if I go over bump and turning at the same time. So sounds like when there is a body roll it happens but not always. I will try to remove everything from the trunk to avoid any false sounds.
sorry for stealing original question.

 

Thanks but you're right, mine is a coupe. Worth noting because a convertible might turn up one day.......

That's a pretty good description of what I experience, albeit also when accelerating and sometimes braking.

 

https://www.clublexus.com/forums/lc-...t-rattles.html

 

Bit of a positive update. Having taken the car in a week a go, the clunk could still not be found. In turn, I approached Lexus HQ, and they were on the case within a few hours and advised me there is a known problem that is most likely the cause. Apparently the problem first manifested in Australia, and the techs out there effectively produced a TSB to advise how it can be fixed. The problem has also been noted and fixed on a UK car, and hopefully mine will be the second such car. It is down to the rear suspension cross member/subframe and the fix involves removing the various bolts securing it to the car, applying lube here and there and hopefully problem solved.

Curiously I mentioned this to my son and he had an almost identical problem on his Civic R. The solution was to again follow the procedure as noted above and again this resolved matters. Strange that he didn't volunteer this when I had him squeezed into the rear of my car whilst creating the noise at will, but in fairness, his noise came from the front of his car.

I'm hoping to get the car booked in for the fix some time in September and will share any outcome then.

 

That’s good if it got resolved and never come back. In my case it is a little different. Mine produces knock sound only when top is in retracted position. And when top is down no any kind of sound.

 

What's the difference between the "retracted position" & "top is down"?

 

my bad. I mean when top is up I hear the knocking noise, when top is down I don’t hear it.
maybe when top is down it muffles the knocking sound and I can’t hear it. Still investigating multiple areas for possible knocking sound.