Vibration/Rattle Noise Above 3700 RPM (only in certain gears).

LunaVyohr

Classhole
Sep 30, 2011
93
0
6
Paonia, Colorado
Alright, I've had this problem recently, with my Supra, where it makes an odd sort of... Vibration noise if it's revved between about 3700 and 4800 rpm. It only makes this noise in 3rd, 4th, and 5th gear. Not first, or second, and not in neutral when it's stationary. I apologize if the description is very vague, but it's extremely difficult to explain what the noise actually sounds like, and a vibrational noise comes closest. I should explain that it sounds as though it's coming from in front of the dashboard on the driver's side. It's very loud and noticeable with the windows rolled up, almost as if it's coming from inside the cabin. I honestly have no idea what it could be - this noise hasn't made any ill effect (yet) on the performance of my vehicle either. I can't 'feel' any vibration coming through the shifter, or steering wheel, and the car itself feels stable when the noise is made.

I'm honestly stumped as to what it could be. Searching, it's possible that it's harmonic vibration, but I really don't know. I wasn't able to find anything conclusive.

For what it's worth, this noise came about after I changed my oil recently, from 10W-30 mineral to 0W-30 Castrol German Synthetic. The top end of my motor was freshly rebuilt about 2500 miles before I changed it. I don't know how that would cause a strange, vibrational noise, but it's worth mentioning.
 
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TheBlueSupra

New Member
Nov 16, 2011
82
0
0
Idaho
Could be something got dropped in a vent, with the right vibration frequency it's amazing how much racket you can make with little things.
 

LunaVyohr

Classhole
Sep 30, 2011
93
0
6
Paonia, Colorado
Update: I took out my gauge cluster to exam my speedometer gear. Found out that's not the problem. The noise sounds as though it's coming from the area by the speed actuator on the far left of the engine bay, near the firewall. The noise is only there when I have my foot on the throttle - if I'm at 3700-4800 rpms, but don't have my foot on the throttle, the noise isn't there.

Any ideas?
 

TheBlueSupra

New Member
Nov 16, 2011
82
0
0
Idaho
You probably already have, but check for loose nut/bolts etc around the engine bay. I had one loose nut on my air filter case, and it rattled like crazy. Took me awhile to find it because other than one loose bolt, nothing shook or rattled when I checked.
 

SRZMK3

New Member
TheBlueSupra;1806451 said:
You probably already have, but check for loose nut/bolts etc around the engine bay. I had one loose nut on my air filter case, and it rattled like crazy. Took me awhile to find it because other than one loose bolt, nothing shook or rattled when I checked.

+1 a rattling noise is the best ventriloquist there is check the body panels in the trunk they love to rattle and so does the glove box. it could be a billion things good luck.