Loud "suck" sound when engine shut off

[Thermo1223]

Air intake's on cars from the factory are made to silence any possible noises relating to it's operation. If you own a performance car/truck then ignore that.

This is why you see excess amounts of plastic tubing that seemingly look useless, just there to muffle the noise.

As long as the filter was secured than yes the sound is the result.

In fact people do this a lot because they like that sound or "think" it makes the car perform better. It usually does not and in fact can make it worse especially on hot days.

 

[InvalidUserID]

I have an intake on my car and when I shut off, it lets out an exhale. I figure it's the intake since it never did so before.

 

[yonyon]

Originally Posted By: threeputtpar

Besides the unfiltered air getting it, does the sucking noise indicate any possible problems? I had recently installed a cheap, lightweight air filter in my A6 as a diagnostic tool and this type of sound was the unintended result. Am I OK as long as it's still filtering the air?


No worries. The noise is a hiss from air moving past the throttle butterfly. When you stop the engine the airflow slows to a stop and the hiss changes producing the schloop. Your engine sucked before and it still sucks now; you can hear it better now because it isn't muffled.

 

[yonyon]

Originally Posted By: TechnoLoGs
And the hole the alternator pulley put in it is about the size of a quarter.


Seal it up man! Just last year I had to deal with a Murano that had been to a quicky-lube two hours earlier where the clamp on the air intake hose was left loose (presumably to facilitate the sale of a new air filter that probably wasn't needed.) That was two hours with a loose clamp I tell you. That's how long it took for the engine to eat a twist tie

and die. Dead hole. These things do happen.

I don't care if you end up using an old sock and a tube of epoxy, but you need to seal up that intake. Try to use something that can't fit through the throttle body. You might get lucky and run with your quarter sized hole for years, but then again, you might not.

 

[babyivan]

Originally Posted By: 147_Grain
Running without an air filter will suck far more than the noise you're hearing.

Either someone is trying to get our ire up or they're really ignorant.
This guy has a few other ridiculous threads on here.... one about no knock sensor, another one about no t-stat, and of course this one about no air filter

If you seriously have to explain to someone why it's a bad idea to run a car without an air filter, I just don't know what to say!

...someone just looking to get some attention I think

Not worth wasting anymore time on this guy and his nonsense threads!

 

[Bamaro]

Originally Posted By: babyivan
Originally Posted By: 147_Grain
Running without an air filter will suck far more than the noise you're hearing.

Either someone is trying to get our ire up or they're really ignorant.
This guy has a few other ridiculous threads on here.... one about no knock sensor, another one about no t-stat, and of course this one about no air filter

If you seriously have to explain to someone why it's a bad idea to run a car without an air filter, I just don't know what to say!

...someone just looking to get some attention I think

Not worth wasting anymore time on this guy and his nonsense threads!

Finally some sense