Liquid Swishing sound in Dashboard

Ok...I have the strangest noise coming from the Dashboard of my 05. Its been going on since I had the radiator fluid changed. In order to correct the issue. I have done the following:
1. Had the Rad Fluid change again and vacuumed to ensure there were no air gaps.
2. Changed the T-Stat (bottom rad hose was not getting hot. Still not)

The following has been checked:
1. No rad fluid on the floor board.
2. Heater still works fine
3. AC works.
4. Engine temp is just a hair bit higher than norm but nothing really bad.
5. bottom rad hose is not getting warm (although mechanic says it did for him, I still fail to have it for me)

The noise sounds like 5 gals of water is flushing through the dash. It get stronger when I rev up the engine. It tends to have a bit of a squeaking sounds, like a hamster wheel. The Mech says its the heater core and wants to charge me $800 to check it.

Can anyone help. I am new to the site...so forgive me if this has been asked before but I did a search and could not find anything related.

Thanks

 

Heater core.

That said, mechanic is out of his damn gourd if he's gonna charge 800 bucks "to check it".

I'm still thinking air in the system. There's a couple of red flags that say you've got air, like the rad hose not getting warm, and that the engine temp is a little higher than normal.

Sometimes it takes a couple of times to get the thing completely burped.

 

^ This

I had the same issue and flushed my heater core and the issue went bye bye. $800! Do it yourself for $0.

 

I seen the drain on the fire wall under the windshield get clogged and the water sometime drains back into the air box under the dash. I had it happen on my 2003 dodge pick up. I used some welding wire to clear out the lines.

 

If the temp control is turned all the way to cold, there shouldn't be any water flowing through the heater core. When you did the coolant change, did you do it with the heater on?

 

put the front up on ramps, open radiator cold and warm it up. itll burp out the air. the higher the front the better. on a hill maybe too...old jeep trick

 

I have burped it twice myself and it still had the noise. Took it too a seperate mechanic and he vacuumed it out from the bottom and said there was no air in the system.
As far as the heater on when the rad fluid was changed...I would say no, it wasnt. I didnt do it myself but at a quick lube...and that was my problem.
How do you flush the heater core? I think its the heater core too...just dont know how to access it.
Thank you all...this has been great help.
I will be posting more...for some damn reason, the truck has been sluggish and getting about 17 mpg. Not the normal 21. Anyways...any advice on the heater core flush would be appreciated. thanks.

 

Were you not advised to NOT install that fish tank instead of the in-dash nav setup?

And welcome to TW

 

Thats funny....excactly what my buddy said when he heard it...but then he thought it might be a keg o rater...and got excited.

Thanks for the welcoming.