Heater blowing cold air?

After the car has warmed up and you turn the heater on all you get is cold air, we pulled the heater core out and had it checked, it was ok we then replaced both of the heater hoses, the thermostat, reservoir bottle, flushed the radiator, replaced the hose clamps, radiator hoses, you let it run and it will start to heat up I then opened the bleeder for the cooling system we get steam and then water will com out close it and soon we get steam coming from the back of the motor it will then start to lug down like it is flooding it self I then open the bleeder and we get steam but the motor smoothies out. Take car for a test drive and the temp will start to climb and it will peg the needle. Checked the coolant level and it will be low top it off and you go through the same thing all over again. Should we take the radiator out and have it professionally cleaned.

Where is the blend door actuator located on the 99 chevy malibu

I replaced the intake gasket on my car put a new thermostat water pump in it and now when I crank it up it has no heat and it sounds like the lifters are knocking. I put the rods back in the same order am I suppose to torque the lifter bolts abd if so what are the specs

1st off just got done replacing lower intake gaskets because of coolant in the oil, after which I flushed the cooling system with one of those cheap prestone kits and refilled. Started engine waited for a temp and checked for heat. NONE! Further more the car heated to around 215 never overheated though. So I changed the thermostat refilled and bled the cooling system. I started it let get a temp. Checked for heat. NONE! Thinking I still had an air pocket I opened the bleeder it was a steady stream. At one point the resevior went empty the low coolant light came on so I added more immediatly while it was running. Shortly after that the resevior overflowed so I shut the car off afterwhich a nasty gas/steam evaporated out of the resevior and all the coolant disappeared. The thermostat opened once during all this I kno because I watched the gauge. I believe I have a blown head gasket and exhaust gasses are getting into the coolant. My question is. Is this the problem and how do I test for it. If not this then what? And how do I test for it?

Thanks for the reply, going for the tester right now. As for the oil it was the first thing I checked and it looks like fresh, clean oil. As for the white smoke most defenatly, not as much as some cars i've seen but defenatly there. If the block tester comes up positive next would be a compression check to narrow it down, right? Again thankx a lot times are a little tough right now and cant afford to take it to the shop.

Tester came in today, used it. Results were positive. I planned on changing both headgaskets if this were the case but I got to thinking this just indicates a leak. It could also mean a cracked or warped head or a cracked block right? And if so is there any definative way to tell which exactly is the cause? Any suggestions greatly appreciated thankx!

Thankx gona do some asking around try and find one, Ill let u kno.

Its been a while, been busy and still got problems. Couldnt locate leakdown tester went a head and tore it down gaskets ended up looking alright had the heads pressure checked. No leaks, and surfaced.005". New gaskets and bolted it back up, started it, ran fine. Let it get a temp and checked for heat. Had it for half a minute then nothing. Also when it got to temp it started over flowing at the resevior for a minute or two and then sucked it dry and the low coolant light came on, I added more water only for it to do it again in a couple minutes. I repeated this for a while thinking I had an air bubble somewhere I opened the bleeder and no matter how long I left it open or when I opened it I couldnt get a steady stream of water. Again it never overheated and I dont kno if this is related but the gas needle fluctuates randomly between half and full. And after all this when u shut the car off u can hear the coolant boiling back into the resevior and it doesnt want to start agian right away you either half to give it a few minutes or give it throttle. Any ideas?
Thankx

For one, you are not to have the bleeder open while the car is running. The bleeder is only for checking that the cooling system is full. You may want to check the water pump at the weep hole on the bottom. My seal had went out on mine and it was only $13 for the part and I replaced it myself.

I have removed the two water heater hoses on the engine firewall side and the water is there on the inlet (thermostat side) but nothing from the outlet (when connected). My understanding is that it has to be one of two things, the coolant flow valve is bad or the heater core is plugged. How do I get to the flow control valve to check it (detailed info will be appreciated) and what's the easiest way to remove the blockage?

Heater problem
1999 Chevy Malibu 6 cyl Wheel Drive Type unknown Automatic 125000 miles

when I turn the heater on the heater does not blow out hot or even warm air. I replaced the control unit thinking maybe it was bad. It still does not work. What else should I check