Brz 2013 AT passenger side rattle
 

So I’ve been having this rattle or a TAPTAPTAP SOUND on the passenger side of the engine bay. It only appears when the car is warmed up. Most audible at low rpms. In the video I’m holding it at about 1500rpm. Regular mechanics say it might be lifters but I’ve seen that for some people the issue is vacuum pump. Please help !!!!!!
https://www.dropbox.com/s/4n9q3pr40y...le%20.mov?dl=0

The "lifters" in our engines don't really move, they pretty much just serve as a pivot point for the rockers and the valve lash specs indicate this is the case as well.

Does it change with engine temps, worse at low/high temps?

Yeah it sounds more audible when the car is warm , there’s no sound of that on the start up at all . Also gets faster with rpms.

Best thing to do is to isolate where the noise is coming from with a stethoscope, or a big screwdriver. Then work from there.

Yeah , that’s what the mechanic did and he said they’d have to take out the engine to
figure out what it is . Have u listened to the sound ?

Yeah, and to be honest it kind of sounds like an exhaust leak. But if the mechanic has already listened to it, he has likely determined that is not the case. It's really hard to tell through the video.

Should I give it to the mechanics at a Subaru dealership?

Sounds like it would be your best option. We can only speculate the issue online, it's much more difficult if you don't do your own work.

Vacuum pump on the AT cars. Common issue

Should I just try replacing it without being sure it is the problem ?

Always confirm first but that sounds exactly like the booster pump. It is only an issue on the ATs.

Yeah I have AT , and I can’t really confirm the sound because every mechanic I go to says it’s the lifters.

It does sort of sound like lifters if you don't have a comparison.

I guess I have an option either to spend money at diagnostics at the Subaru dealership or just replace the vacuum pump hoping that’s the problem