Strange hammering sound after car is parked

[Sally M]

Sorry... I am new to the forum and think I posted this in the wrong area a little while ago so will put it here which may more likely be where it belongs...
I have noticed, should I happen to be near the car a short while after I've parked it that there is a sound like someone is hammering something under the hood. Lasts maybe 8-10 "hits" then stops. Any idea what could be causing this? Thank you!

 

[WannabeST]

Sorry... I am new to the forum and think I posted this in the wrong area a little while ago so will put it here which may more likely be where it belongs...
I have noticed, should I happen to be near the car a short while after I've parked it that there is a sound like someone is hammering something under the hood. Lasts maybe 8-10 "hits" then stops. Any idea what could be causing this? Thank you!

When you say there is a hammering sound, is it loud? or does it just sound like taps.

And also is a short while like a few seconds after parking or a few minutes?

 

[isis]

It’s the blend door behind the glovebox. It’s toast.

 

[Sally M]

When you say there is a hammering sound, is it loud? or does it just sound like taps.

And also is a short while like a few seconds after parking or a few minutes?

It has varied quite a bit... but never less than 5-10 minutes and sometimes longer....

 

[Sally M]

When you say there is a hammering sound, is it loud? or does it just sound like taps.

And also is a short while like a few seconds after parking or a few minutes?

Forgot to say that it is fairly loud.

 

[Sally M]

It’s the blend door behind the glovebox. It’s toast.

I'll tell the service dept that in the morning.... I have no idea what that means but hope that they will.

 

[Capri to ST]

It’s the blend door behind the glovebox. It’s toast.

That was my first thought also.

 

[Capri to ST]

I'll tell the service dept that in the morning.... I have no idea what that means but hope that they will.

Our HVAC system has three actuators, little motors that move around different parts of the system when you make adjustments or after you shut the car off. One controls the temperature, one controls where the air goes, and one controls whether air is fresh or recirculated. That last one is the one behind the glove box which seems to be the one you're hearing.
They have these cheap plastic gears in them which can strip out over time, and when they do the actuator keeps trying to move them but since the gears are stripped out that doesn't happen, and the whacking sound you hear is the motor turning something trying to function. This is a known issue in our cars and in many other modern cars.The one behind my glove box is also making noise and I'm getting ready to replace it. It's annoying, but not a huge deal otherwise.
Here's a thread discussing it which probably has a lot more information than you need, but I will link it here in case you find it helpful-
https://www.fiestastforum.com/threa...cking-sound-part-numbers-video-install.22458/

 

[M-Sport fan]

Sometimes my actuators even 'clack' more than ten minutes after shut down.

IF there was a way to fix these things permanently, I would do so, but until there is I will just live with the noise.
(I usually park far enough away from anyone to even be embarrassed by the loud chicken pecking sounds.)

 

[Sam4]

I'll tell the service dept that in the morning.... I have no idea what that means but hope that they will.

It controls the airflow to the floor / dash / defroster. If you change flow, you'll hear the blend door moving to adjust the flow. It's got a little broken tooth, and skips like a bad fan when you power down the car. and sadly, they get big bucks to change it...

 

[SteveS]

Or you can buy the less than $20 part and replace it yourself.

 

[isis]

The one behind the glovebox controls the fresh/recirculated air. The sound you hear after it is off is the car trying to seal up when parked. With this broken I got lots of interior fogging and some frost even when the car sat overnight. I think it stays open to let the vents air dry for a time after it’s been running.

 

[Sally M]

Or you can buy the less than $20 part and replace it yourself.

Fortunately since I bought the car there recently they are going to take care of it without charging me... but that's definitely the issue.

 

[Sally M]

It’s the blend door behind the glovebox. It’s toast.

As I suspect you already know you were 100% right. Thanks.

 

[Sally M]

It controls the airflow to the floor / dash / defroster. If you change flow, you'll hear the blend door moving to adjust the flow. It's got a little broken tooth, and skips like a bad fan when you power down the car. and sadly, they get big bucks to change it...

Fortunately for me this time they are going to take care of it since I just bought the car there a few months ago. Thanks for the added info.

 

[Sally M]

That was my first thought also.

You were both right! Thanks.