Overheating too often.

It's overheating everyday and I don't have heat anymore!
 
I could start it up and run it for 5min and it will be overheating.
I've changed the waterpumpabout 6months ago and thermostat just the other day.
 
I felt the heatercore lines and the top radiator hose and they are all cold. the only onw that was hot was the bottom hose coming from the waterpump. The overflow coolant was high and hot.
 
What can it be? Blocked Heatercore?
Can I pull the thermostat out and run it that way? 
 

Do not run without the thermostat. Have you looked inside the radiator to see if the coolant looked okay and how long has it been since you had the system drained and flushed?

You may have a broken impeller in the water pump. It sounds like the coolant is not flowing.
I would suggest removing the thermostat, make sure that the coolant is topped up in the rad, leave the rad cap off and watch in the rad to see that the coolant is circulating. If you see coolant circulating, install another new thermostat.
If you don't see the coolant circulating, replace the water pump.

I would do what chevy lover said, then if it is the thermastat or water pump and you replace either and it works fine, I would flush the system just in case there is any debris or excessive dirt in the system!!

I've been filling up the rad. everyday. There are no leaks anywhere that I see. I've checked the floor also, nothing either. I think it's burning off.
 
Flushed the heater core and reverse flushed it. Then flushed the whole system with prestone rad. flush. It still has no heat but when idleing it sits about 210 and when I'm driving its about 240. So I think I'm getting somewhere.

quote:

ORIGINAL: 96Ls4Dr

I've been filling up the rad. everyday. There are no leaks anywhere that I see. I've checked the floor also, nothing either. I think it's burning off.

One thing for sure, the coolant is going somewhere. Have you checked your oil level to be sure it's not mixing into the crankcase due to a leaking intake manifold gasket?

Yep Oil is good, brown and at the right level.
 
I think if it's going somewhere it's into the exhaust.
I read somewhere that if your exhaust is white your burning antifreeze. Mine was white for a while and when I had just plain water and some rad. flush and it was still white.
It also has a really rough idle.
 
My Sevice Engine Soon light is on now too. It blinks when it's idleing but is on steady when driving. I know I need to get that checked out but the nearest place is a half hour in the wrong direction.

Well, 'white' exhaust can also signify a too lean air/fuel ratio. If it is from coolant, though, it means a blown head gasket, warped head, or cracked block. I had an '82 Cutlass once that showed billowing white smoke on take-off from a dead stop and it was a bad modulator valve letting ATF get into the engine. That was a simple fix.

quote:

ORIGINAL: Chevy Lover

You may have a broken impeller in the water pump. It sounds like the coolant is not flowing.
I would suggest removing the thermostat, make sure that the coolant is topped up in the rad, leave the rad cap off and watch in the rad to see that the coolant is circulating. If you see coolant circulating, install another new thermostat.
If you don't see the coolant circulating, replace the water pump.

 
automotive water pumps are cetrifugal?

Most all of the water pumps used are centrifugal.

That is true about waterpumps being centrifugal but what I believe he ment is that there could be a broken fin inside the water pump. My buddy's fullsize chevy had broken fins inside his water pump that luckily stayed right there without circulation. I don't know how else to describe it besides a fin or blade. 

Most impellers in modern water pumps are stamped steel.  They are spot welded together.  Most common failure is the bearings, but if the welds are poor, the impeller can break loose of the drive hub.