Mokomaki

Hello. Couldnt find this problem googling or searching this forum.

So whenever i turn the ignition on while in P, the brake fluid reservoir will buzz pretty loudly. Some time after a few minutes it will stop for a few seconds and continue again.

Noticed that this also happens with the engine on even when just stopping with D on.

Brakes feel good and the reservoir fluid is just below the max line.

What could be the problem?

1996 4.2 v8 205 miles.

Mokomaki

https://www.dropbox.com/s/6ourkx3eq9..._0722.mp4?dl=0

theres some footage. Isn't that loud in the video, but is very loud to the cabin doors closed.

silverd2

It's not your reservoir buzzing...more likely the pump valve unit (for heater control) between the reservoir and the fresh air intake.

Mokomaki

Point there! Since my sides are only blowing Hot. Is there a fix other than replacing the 300€ pump?

silverd2

If it is indeed that pump running, it's main purpose is just the "restore" feature on the climate control (running remaining heat for passengers after the motor is shut off).

While it's whining, try unplugging it (cylindrical plug between brake booster and fresh air intake)...this will at least let you know if it's causing the noise and the climate control should otherwise operate fine without it.