2006 Sloshing sound behind Dash

If you are going to burp it. I would do the bubble test also. When my 2005 started having issues that was the first sign my mechanic did. Just take the radiator cap off when it isn't real hot. Start the truck. Look into the radiator and watch for bubbles. It wont take long if you have a Head Gasket issue. If you see bubbles that is exhaust gasses escaping and coming up through the radiator. My bubbles were small like what you see in a soda can when you open it and I drove around for almost a year with the truck before I had it fixed and it never got hot or caused any damage. The one gasket went around 137,000 miles and was around 1/8 of an inch hole. I now have 220,000 something miles and its still going strong.

 

I wouldn't jump to head gasket unless it was an 05

 

Start the truck cold with the radiator cap off and look for bubbles. Get some air out by squeezing the upper radiator hose. Put the radiator cap back on before the engine gets hot.
Watch coolant level. It will be up and down slightly. If the level drops and keeps dropping, you have a problem. Make sure your radiator cap is good.
Smell the exhaust fumes, especially just after first starting the truck. If you smell the sweet smell of burning coolant, the coolant is leaking into the cylinders.
Check the oil filler cap after a longish drive. A milky residue may indicate coolant in the crankcase. Residue in the filler cap after a short drive but not a longer drive is condensation.
Milky "chocolate milkshake" on the engine oil dipstick. This is usually a definitive sign you have a head gasket issue. There are a number of things that can cause this, but on 05-06 Tacomas, it's usually a head gasket.
Good luck.

 

Most auto parts stores rent a Block Tester which includes a color changing fluid to detect if exhaust gases are present in the cooling system.

 

I took the cap off and started that car and the fluid in the radiator neck rose and started to spill out. Should I try it again at an incline or is something wrong?

 

This was the first the first symptom mine had of head gasket failure

 

That’s common.
Like was explained earlier. It helps A LOT if you have a spill free funnel.

The water pump is pushing the water. The water isn’t moving when the truck is off or first started.
It takes a bit for the water in the cooling system to get flowing.
And since the cap isn’t on, the water will take the path of least resistance. There isn’t any resistance when the cap is off. So, naturally the water wants to come out the radiator fill port.

If you use the spill free funnel, the coolant will stay in the funnel when it gets pushed out. Then it will eventually settle back down.

 

Same lol

 

Was the truck bought from a dealer? If there is a warranty with this truck look into it. You may need it.
No reason to burp a coolant system that has not been opened up recently.

 

I had that water noise when the A/C refrigerant was low. Of course it only made that water noise when the A/C was on.