Please help identify source of engine noise

Its your brake booster pump. Seems louder than it needs to be. I can hear mine sitting in the driver seat. Always comes on when I open the driver's door and will cycle on again after using the brakes a little bit. Its normal. What is not normal is if it cycles on when you are not using the brakes. That is a pretty good indication that there is a leak

I swapped out my master cylinder (accumulator?) and it definitely helped, but I have read of others that had the cycling going on for years.

 

Monitor how often you hear the noise... Once you hear it more than once in a minute its time for a brake booster pump swap.

 

houston, all systems normal

 

I normally hear this sounds whenever I am coming to a stop (using brakes of course) and it goes away as soon as I am fully stopped. Perhaps it's not the same sound, but I definitely do not get it when the vehicle is stationary, unless the car is not on and I open the driver's door.