# Yet another mystery noise

**URL:** <https://community.cartalk.com/t/yet-another-mystery-noise/7476>\
**Category:** Maintenance/Repairs\
**Created:** [November 20, 2007, 3:03am UTC](https://community.cartalk.com/t/yet-another-mystery-noise/7476 "2007-11-20T03:03:38Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![JamieFR](https://avatars.discourse-cdn.com/v4/letter/j/c57346/32.png) [@JamieFR](https://community.cartalk.com/u/JamieFR)\
**Post date:** [November 20, 2007, 3:03am UTC](https://community.cartalk.com/t/yet-another-mystery-noise/7476/1 "2007-11-20T03:03:38Z")

</div>

Hi again. Yes, I have another mystery noise. I wasn’t sure if I should have just used the same post, so I just created a new thread. Here are the details:  
  
  
  
 To me it sounds like it has something to do with liquid flowing through something. I can hear it when I am slowing down or speeding up, but it isn’t that loud. I can hear it prominently when I am at a stopsign or stoplight. I can hear it a little bit when I am in park. However, when I turn the AC on it is very loud.  
  
  
  
 More info: I added some anti-freeze to bring it up to the correct level and I also added a quart of oil because it was low.  
  
  
  
 My gut, which was wrong with the power steering pump situation, is telling me that it is the water pump.

---

<div class="post-metadata">

**Author:** ![Joseph\_E\_Meehan](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/joseph_e_meehan/32/21_2.png) [@Joseph\_E\_Meehan](https://community.cartalk.com/u/Joseph_E_Meehan)\
**Post date:** [November 22, 2007, 3:55pm UTC](https://community.cartalk.com/t/yet-another-mystery-noise/7476/2 "2007-11-22T15:55:38Z")

</div>

```
I am going to guess there is air in the coolant and right now at least some of it is in the heater core.
```

---

<div class="post-metadata">

**Author:** ![mcparadise](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mcparadise/32/32_2.png) [@mcparadise](https://community.cartalk.com/u/mcparadise)\
**Post date:** [November 22, 2007, 7:00pm UTC](https://community.cartalk.com/t/yet-another-mystery-noise/7476/3 "2007-11-22T19:00:04Z")

</div>

I agree. Bleeding the air out of the cooling system is the first thing to do.

---

<div class="post-metadata">

**Author:** ![JamieFR](https://avatars.discourse-cdn.com/v4/letter/j/c57346/32.png) [@JamieFR](https://community.cartalk.com/u/JamieFR)\
**Post date:** [November 23, 2007, 3:40am UTC](https://community.cartalk.com/t/yet-another-mystery-noise/7476/4 "2007-11-23T03:40:29Z")

</div>

Air in the coolant? How does that happen?

---

<div class="post-metadata">

**Author:** ![JamieFR](https://avatars.discourse-cdn.com/v4/letter/j/c57346/32.png) [@JamieFR](https://community.cartalk.com/u/JamieFR)\
**Post date:** [November 30, 2007, 4:54am UTC](https://community.cartalk.com/t/yet-another-mystery-noise/7476/5 "2007-11-30T04:54:37Z")

</div>

Here is what I found out today. I had a mechanic friend check it for me and he says that it is the a/c compressor and that it won’t effect any other systems in the vehicle.