Install pics here:
https://www.clublexus.com/forums/sho...t=making+noise

After my friend and I installed the carson exhausts on both our GS's, we both developed a rattle. Mainly you hear it going over bumps or coming to a stop and it will continue to rattle till you get off the brake. We've both looked at it several times and there is clearance every place it could hit something. So this past weekend I had a Lexus Master Tech look at it and couldn't find anything wrong with the installation. Wierd thing was it didn't rattle when I went for a ride with him, until we pulled back into the dealership and finally he heard it. Only problem we couldn't duplicate it on the lift.

Anyone have any ideas, its driving me nutz!!!

 

My carson rattles once and a while too.

edit: when i climb hills and and turn under circtai circumstances it rattels on the passenger side. It sounds like its hitting the rear bumber, ive been meaning to adjust the hangers to see if it helps.

 

I have clearance, the tips are dead center on the stock bumper. I've shook it pretty hard and can't seem to get them to hit the bumper so I doubt thats it.

 

Mine are dead center as well, and I still think its hitting the bumper.

 

Mine was hitting on the Tom's RLCB cross piece where the pipes went over and with only about 1/8" clearance it would hit slightly on sharp bumps. My solution was to bend the rear muffler hangers a bit for about 1/4 to 3/8" clearance. No more problems at all. If you don't have this brace though, I don't know where it might be hitting...

 

Check your tow hangers (tiedowns) underneath your rear bumper. 99% positive the exhaust canasters (not tips) is close or actually touching it after driving for several miles. You will either have to cut a piece of the hangers out for more clearance or totally remove the hangers all together. Ive seen this problem happen on several cars now. Including my own when I had it...

Edit: Make sure when you are checking this problem out that the exhaust is hot from driving. If the car sits overnight and you check, you will see a 1/4" gap between the canaster and the tow hanger. After driving for 15 mintues, you will see the gap slowly disappear and the canaster will be almost touching the tow hanger.

Why this happens, I have no friggin idea......

 

I can verify what Ken is saying: Make sure you check the clearance after the exhaust is hot ( the exhaust will grow do to thermal expansion after heating up ), I had a problem with the passenger side cannister hitting the tow bracket ( actually expanding back enough to hit the bracket,whenever there enough motion to cause contact - causing a rattle ) after the car warmed-up. This did not occur when cold and certainly not sitting in the garage when I first started checking clearances. I had to grind some of the towing bracket away to get adequate clearance. The driver side never had the problem.

 

Very helpful info. Thanks. I will need to bust out my grinding wheel.

 

Got the tie down hooks grind out. No more rattle.

 

Excellent... Glad it worked out for you!