pmaximus

Howdy,
I recently purchased a 2000 GS300 from a family friend and he let me know if this "mooing" sound coming from behind the dash, he said he took it to a mechanic and they couldn't really find anything wrong with it (it doesn't affect the driving experience or anything) and they'd have to pull the dash apart with a great fee, so it's just kinda stayed with us. Like I said earlier, it doesn't affect the driving experience and I don't notice it being a danger to the car, it's more or less just a nuisance. Typically, it will moo when I start the car or randomly when I'm driving, when I apply the brakes, it almost mutes the noise a little bit, but not completely. Also, when the AC is running high (living in Texas in the summer, it's almost necessary) the car moos very loudly and stays mooing for a while (about 10-15 seconds.) Sometimes, as shown in the video, it also sounds like there are cogs turning behind the dash. This occurs randomly, sometimes when I start the car and sometimes when I'm just driving. I would really like to know if anyone has experienced this problem, and if so, how to fix it. Please help and thanks.

https://youtu.be/2IKmvuAYrrI

Mr Jokster

iTrader: (8)

Not quite sure what to listen for, I'm listening for a "mooing" sound, but hear none. I do hear another sound that sounds like the infamous servo motor (which does correlate with the A/C).

Is there there a better description other than mooing that you can give, or is mooing exactly what you're hearing? When I think mooing, I think of a hum

btw, welcome to Club Lexus

Please dont forget to search because in the 18 years this car has been around, pretty much EVERY problem has been come across and corrected

Mr Jokster

iTrader: (8)

Mr Jokster

iTrader: (8)

Ok, I just reread your post, the "cog" sound IS the servo motors on the vents that I speak of Plenty of threads on this Be sure to check our FAQ/DIY thread stickied on the top of the 2gs theads

pmaximus

Thank you very much! Any idea what the "mooing" or buzzing sound could be?

Mr Jokster

iTrader: (8)

Ok, if its a buzzing sound, most likely its the master cylinder (which is a normal sound). To replicate it, press the brake pedal 5 times and take a listen, is that the same "buzzing" sound you speak of? If it is, its just the electronic brake booster resetting the pressure.

pmaximus

I went into my car to test what you recommended and it didn't sound the same, I was recording and got the full extent of the mooing/ buzzing sound on video, here is the link:

https://youtu.be/3zjmltioyIM

Mr Jokster

iTrader: (8)

Actually, it still could be the servo as I mentioned. Its the teeth of the gears grinding, that would have to be confirmed by another member as I vaguely remember it making that same sound when its very bad, but you can search "buzzing noise (or sound) behind the dash" and read what comes up. However, being that it comes on right after startup, it sill can be the master cylinder as I mentioned.

Another test to rule it out. Open the hood and have someone turn the key on (or turn it on and run out real quick) and listen for that sound where the booster is right behind the gauge cluster right there out in the open. If anything, it will be very loud now that the hood is open IF it in fact is the cylinder... The other thing to do, make the sound happen again and put your ear under the dash and listen to see if its more located behind and under the radio. That is where the servo is.


As I type this, I'm more certain its the servo