Engine Overheating; Changed Thermostat, still overheating!

[Mobetta72]

2004, Chevy Tahoe, 5.3, 2WD
My Tahoe started overheating a few days ago with antifreeze/water burping out of the reservoir. I thought it was the thermostat so I changed it, but that didn’t help the problem. When idling with the radiator cap off, the antifreeze/water starts burping out the reservoir. What’s the problem? Please help! Thanks

 

[Rivieraracing]

When you did the thermostat, did you hose out the block and radiator real good and did the water flow out of everything good? No blockage? Might want to think about checking out the waterpump for failure!

---------- Post added at 06:24 AM ---------- Previous post was at 06:22 AM ----------

Dumb question but have to ask anyway, is the serpentine belt still on the pulleys? Sorry, I had to!! lol

 

[brassknucklemafia]

worse case and you wont like it. head gasket. i had the same problem and that was the case for me, no water in the oil or anything like that or any other hints to let me know that was the case. ( it was on the exhaust side and not the coolant side of the gasket, on the drivers side that let go) changed my head gaskets and that was the end of the problem. but the first thing i did was change the thermostat thinking i had a bad or sticky one, I even took out the radiator and flushed it twice, just to make sure there was no blockage (even though it was less than 6 months old) so i feel your frustration. because we all know that damn coolant isn't cheap, just to watch it bubble and gurgle away. hope that helps.