ls4gs4ownr

I have a 91 LS400 with 213k miles. There are 3 distinct noises, all on the left side of the car. 1. A rattle noise in both the left front and rear when going over bumps at 25-35 mph. 2. A low speed rumbling noise which transferres into the steering column and 3. A clicking noise when going over bumps at any speed (has been with the car for over 100k miles now). Sounds like someone tapping a penny in the corner of the windshield. Right side is very tight as is supposed to be.

I have changed all 4 sway bar bushings, all front and rear lower control arm bushings, rear carrier bushings, all 4 strut rod bushings, both front ball joints, and left front wheel bearing. The front shocks and spring cushions (not the shock tower bushings), tires were all replaced but made no difference.

I plan to keep this car for a long time so any thoughts before I continue on with front upper control arms, a steering rack (never replaced because it doesn't leak) and upper shock mounts?

Thank you!

ls4gs4ownr

Just an update. I changed the left front strut/shock tower mount and it didn't make any difference. With 213k miles, a few dealers told me that it was long overdue, however, it appeared to have another 100k miles of life to go.

Next, I changed the upper control arm and what a difference. I spent a couple months trying to decide if I should get the diazen bushings and I'm glad I replaced the whole arm instead. The upper ball joint was bad and 90% of the rattle noise is now gone. The remaining is coming from the rear.

I will update later when I replace the rack to eliminate the low speed vibration noise into the steering column.

ls4gs4ownr

Just another update. The remaining rear rattling noise is now gone. It turned out to be the front muffler/resonator rubbing against one of the heat shields. All rattle noises are now gone.

I changed the motor mounts and although they were bad, there was no noticable change in noise/ride.

I replaced the steering rack with a rebuilt Lexus rack along with the outer tie-rod ends and the steering is very precise, however, the vibration noises are still in the steering column.

Best bang for the buck to date: The left front upper control arm, left front wheel bearing and steering rack.

Will update again when column noises are fixed.

LEXTEK1

Change the transmission mount. That shoud make a huge difference.

As for the steering noise. Check the wheel bearings. Or the tires!!! Clean the P/S Pump Screen and the rack screen.