HardMax86

Hello guys, i purchased a stock SL55 02', 150k kms in january, i did some things (ic pump, soft trunk close, battery leakage from teleaid), but now i would like to take care of this weird sound.

Car is running perfeclty fine i guess, engine and transmission, abc ok. I can hear a knock coming from under and behind the seat, not from the trunk. It's like something hitting the frame with a little hammer, only when i am turning. No sound when i ride on a bump, no sound when i brake or accelerate (i think). When i go to the left then to the right, clunk. Another thing i noticed, when i stop the engine after i drive of atleast 20min, i can hear this same sound (i guess) under the car. I can hear it clearly. It's like hot metal cooling down after a ride if you know what i mean but loud. Is is normal ? I could make a video if needed.

I thought of a relay (if there is) inside the end of the gearbox, of something moving freely but i have to go under the car to check this.

Thanks for your help !

Max

BenzNinja

iTrader: (4)

hi
maybe your transmission mounts/suspension
there are some mounts everywhere on this car that must be replaced especially if your car is a 2002

lilbaggie

I'm in the midst of troubleshooting what I think is the same noise on my 03 SL55 w 33k mi. It's a faint knocking—a slightly metallic noise coming from behind the seats either under the car or behind the rear bulkhead. I initially thought it was a tick not unlike an exhaust cooling but it's too rounded a sound and mine is also rhythmic (about every 20 secs). I'll hear it for awhile after shutting off the vehicle, maybe up to an hour. I suspect it makes noise while i'm driving or when the car is on, it's just not as apparent with engine and road noise going on.

I had the car up on my home lift, immediately after driving and isolated the noise to this spot:


It's coming from behind that heat shield…

My indy mech has not had time to inspect yet but I suspect it's part of the ABC system as there's a valve block where lines run to.

HardMax86

Hum ABC, not good... It seems to be a tick relay sound. Do you have this same noice when you take a turn? Not a loud but pretty annoying for this type of car. I will measure the time between the two ticks,but i guess it's periodic too. let me know if you investigate more, thanks.

lilbaggie

Mine is definitely persistent not dynamic. I thought it might be the same as yours because yours is evident after the car is off while no components should be moving. I also thought it was a tick at first but the more I isolated it, realized it wasn't.

If you get a chance, next time you drive and park, pop your head under the car in front of the rear driver's side wheel. It wasn't until I got a lift that I pinpointed the sound. It initially sounded like it was behind the passenger seat. I had an ABC flush not too long ago and everything was in spec but it might be the valve block at the very initially signs of going.

HardMax86

So i tried many things today. I rode about 15 minutes then i stopped and recorded this the noise :
The noise is in reality stronger than what you can hear on the video. The tick can be heard every 6 sec, the more i wait the more it takes time, and stop 15 minutes after turning off the engine. Then i removed the two fuses that i believe are the ones used for the ABC system, no change, then i removed the two fuses of the gearbox, no change too. Next time i will disconnect the auxiliary battery, it be will clear if it's something related to some actuators or not. Abc fluid level is ok, but i don't have dipstick for the oil tranmission. When riding the car, i can hear the little noise when i brake hard or accelerate a bit. I know i have a little leakage coming from the gearbox cover i believe, i think i have to change the seal.

HardMax86

So, i disconnected the auxiliary battery and i still have this noise, maybe i should try to disconnect the primary battery but i think it's only used for the starter. Veryyyyy weird