07 IS 250 AWD 135k miles
Hello! I’ve been trying to diagnose this clunking issue that happens going over quite literally any bump. Big bumps (railroad tracks) causes a lot of metal sounding clunking. Replaced sway bar, checked front brakes thoroughly, control arm seems fine visually, motor mount seemed fine visually? Mechanic said something in the struts could have some play?

Before it started making this clunk over every bump, it would only clunk or “POP” once when accelerating from a dead stop like a red light. Noise always came from directly in front of me on driver side and I swear I could barely feel a slight thud in the accelerator pedal when it popped. Didn’t happen every time, but I noticed if I stopped right before or on a bump in the road with my driver side front wheel over it, the pop would occur after the acceleration and play from uneven ground. Struts maybe?

The other day everything was fine but I was driving on the highway and suddenly there was slight thuds over every bump at 70MPH. When I got into town the thuds turned to clunks and it turned very loud!

could it be possible that the motor mounts are visually fine but cracked underneath, needing removal to actually see damage?

 

It's most likely your LCA bushings, i had the same problem. Thought suspension was gone, LCA bushings gone, they are factory too soft. Try RCF ones, firmer and won't cause inner tyre bite like the normal is250 ones.

 

thank you, I’ve read around and that seems to be a common issue, I’ll check it out.

 

It could also just be a strut had the problem going down my pebble drive way would heat like a tapping in the driver side engine compartment almost. I got KYBs on it now took the sound right away. There paired with H&r springs

 

Mechanic ruled it down to strut and recommended new KYBs...really it is just a guess at where the clunking is coming from after checking sway bar, control arm, brakes, etc.

Will probably give the new strut a shot after checking the motor mount.

 

Check the subframe bolts and steering rack bolts for looseness.