jag_600

I hear a light scrape....scrape metallic sounding noise between 15-20 mph, sounds like it is from the rear half of the car.

- can't duplicate it when it is on the rack
- brakes check out fine
- wheels check out fine
- does not occur during braking
- haven't heard it during coastdown

usually hear it when the sound bounces off a parked car or a building

wondering if it might be a vibration or something from one of the heat shields, haven't found anything loose

my first guess was a warped caliper, that is what it sounded like a: slow, occillating, metallic scrape that usually happens 2-3 times then goes away above below 15mph and above 20mph.

Woogie

It could be your wheel bearings. Jack the car up or rack it up and shake the wheel UP AND DOWN. if it shakes, then your bearings are bad. remember tho... check front too.

jag_600

Wheels are rock solid, no play at all, still poking around.................

Woogie

hmmm... there could be something wrong with the connection between the drive shaft and the rear differentials. Take it into a good shop or maybe even a lexus dealership and try to find out what it is.

VVT-i

Don't forget to check for cracked exhaust mount to the transmission. On the SC400, just right under the transmission bell housing there is " W" shape metal bracket that connected both exhaust pipe together.This bracket used 2 14mm bolts and bolted on the transmission. You may need to this bracket for any sign of crack where it bolt to the trans or to the exhaust.

Woogie

if it was an exhaust mounting bracket problem, wouldn't it occur at a certain RPM range? He said it was only audible at 15-20... well it could be just a first gear problem then cuz first gear is lighter so maybe i guess what you said does make a little sense. this has got me thinking.

smelkony

I have the same problem that occurs when slightly accelerating. I read some where on the forum that it was the heat shields on the cats that got loose or something. He said he took it to a muffler shop and they welded the shields together ($40) and it stopped the noise. I havent do this yet , but if you get it done please post your reply or pm me.

dinobert

I've had this problem too, mine makes a light rattle sound (sounds like it's from under the hood) any time I'm going betwen about 15-25. Twice Bell Lexus said they fixed it, by re-tightening a "Shield" probably that heat shield in question, but I hadn't asked. Both times it lasted about 1-2 weeks then it started up again. I'd love to have that shizzy welded up if this has worked for someone else.

Do you know which shields specifically?

Thanks,

~J

RTIS250

iTrader: (9)

Check the brake backing plates to see if they are contacting the outer edge of the rotor... seen it happen a few times, and its hard to track down...

/Aerostar\

iTrader: (2)

This almost has to be a brake problem, double and triple check them

dinobert

For me this happens when I'm accellerating or just idling down though. It also happens during braking too, but it's the loudest when I'm idling down from 25ish.

~J

smelkony

I got my heat shields removed and the sound is still there. I thought because the car had 70,000 miles on it that the engine had somekind of problem, but today i drove a lexus parts employees sc300 with over 200,000 miles on it and he didnt have that sound.