Loud noise in engine

When I turn my car on (2008) I get this jet engine sound from the radiator area. It's not there all the time, but I would say most of the time. Is it normal?

I have an MP3 of the sound, but the forum won't let me upload it to show you.

 

I topped off the coolant this morning in both reservoirs. It's been low for a while. As far as I know the water pump is working fine, but I don't really know how to check. The car is at 192,000 miles. I've owned it since 160,000. Other than this roar coming from the engine when it's running the car seems to be working fine. The sound goes away from time to time when the engine goes completely quiet, but comes back to life for most of the time it's running.

 

I'm not seeing any pink residue, but I'm still looking around. There are a couple spots near the closest belt wheel that look more like pink paint than crystals. I filled the container in the front of the engine and the one beside the battery.

 

I thought I did that. I had to take the big plastic shield off the front of the engine (and broke two of those plastic screws) in order to check the radiator coolant level. Either my angle and light was bad, or the reservoir was damn near empty. I'll have to take a look for that air bleeder. There was a cap on the passenger side right next to the reservoir that said to open it before filling and I got an air hiss when I opened it.

Anyways, I drove for 5 minutes to get new air filters (my cabin filter looked like a tree was taking root). When I turned on the car I got that roaring sound. When I got going I decided to turn off the air conditioning and the roar went away. I parked in front of Autozone and played with the A/C for a few minutes and it seems that the sound is the big fan in the front kicking in when the A/C is on. As soon as I turn it off it goes away. I pulled into the driveway and got out which is where I notice the roar the most. This time I parked with the A/C off and the car stayed quiet on battery for a couple minutes. I turned the A/C back on while idle and the engine roared back on again. Now that I think I've discovered the source of the roar, my follow up question is: is this normal behavior? If so, I'll ignore it and focus on other issues.

 

It's at 192,000 miles and as far as I can tell it's on the original battery. I bought it at 160,000 miles. What do you mean by "cycle?" How often does it make that buzzing noise?

 

I have to take one of these air filters back to the store to trade. When I come back I'll let it sit and time it and let you know.

 

How long should it run with the a/c on to make it a good test? I drove it without a/c for 5 minutes, regenerated 75Wh, and let it idle in the garage for 10 minutes without the ICE coming on.

 

Not to derail my own thread, but I got a new sound coming from the engine (or just finally noticed it). I noticed it while my car was sitting idle in the garage waiting to see if the ICE would come on. I might have heard it while the car was in motion too. This YouTube video isn't my car, but it's the exact same sound (starts around :15 but you can really hear it at :50). The car in the video is making that pumping sound continuously while mine is only occurring for two seconds every couple minutes. What is this?

 

I turned it on and the engine came on for about 20 seconds then went silent. I turned the a/c on and within 5 seconds the engine and the radiator fans came on. I let the a/c run for about 30 seconds then turned the a/c off. It immediately went silent again. I'm not sure if I'm doing this test correctly.