How you burp the heater core

What kind of vehicle?

blend door is inside the heat/ac box that contains the heater core that you changed. It is vacuum operated, so check all of your vacuum lines. There is a vacuum line that goes thru the firewall, right above or below the 2 heater hoses.

your heater core might be clogged or have an air pocket in system for this, when engine is cool, take radiator cap.off, if you have a no spill funnel to use, then set it up and start.you car and fill your no spill funnel and let it run to burp your system if you dont have one, then take cap off, place a bucket under.your radiator, start your car, let it run till warms up, watch your antifreeze if it starts to burp.and lower, then you had air pockets, it also.helps if you raise the front end of your car to a little if your heater core is clogged feel your heater core hoses, the top one should be hotter then.the other one, if not, back flush your heater core to do this, wait till your engine cools, take off both.heater core hoses then get about 6 feet of heater hose the same size, place about 4 feet of hose on the top heater core line and place a clamp, put this hose into.a.bucket, take the other two feet of hose and place on the bottom heater core line and clamp then take your garden hose and turn water on, into the bottom heater core hose, this will push all the antifreeze and junk out the top hose that goes into.the bucket do this till you have clean water coming out now if you also have.an air compressor, after you have clean water, do the same thing with the air hose, but only use no more then.20psi of air, you dont want to screw the heater core up after you did the air, I.always run more water though it.again to make sure everything is out after you have done this, put the heater core hoses back on, and fill system, start your car, and do as I.said above to burp the system also check your radiator cap, I will always replace them if they.are more then 5 years old, the gasket goes bad, for every psi you lose in your system, you lose heat, I forgot how the math works, but it can be 10 degrees of heat lose do.a.back flush when your eng is cool

make sure when you put in fluid that you burp heater core might be air in it.

Check the Thermostat sounds like it is faulty and is opening when it should be closed. Cheap fix around $15 doing it yourself,

Air is getting into the system. Tighten all hoses and do not overlook the hose going to the expansion tank. When car cools that hose sucks water back into system but if not tight it will suck in air. Could be why you constantly have to "burp" the system.

THERE IS NO HEATER CONTROL VALVE ON THE WATER HOSES. NEW HEATER CORE. INLET LINE right before heater core hot, outlet after core look warm. Burped cooling system 5 times with engine at operating temp. Installed homade burp VALVE right after heater core outlet(high part of hose). Still no heat. Removed water pump, impeller still in good shape not stripped off shaft. Removed heater core hoses flushed water thrue the connections on the block to the water pump INLET and outlet. flushed water thrue heater core and hoses. Going to put it back togeter today. Used known good gauge to check water temp for operating temp in test. 195 f

The heater needs coolant in the vehicle to operate. If you're leaking coolant somewhere, and the level falls to low, it won't get into the heater core.

First, fill the coolant - heat extracted by the coolant from the engine is used to heat your climate-controlled air. If you don't have enough coolant, you won't have the ability to heat your interior. Once you've filled the coolant, burp the system (click my screenname, go to Tips and Tricks, and the procedure is there). That should do it.

If you still don't get heat, disconnect the heater core hoses, put one in a bucket, and use an air compressor to blow into the other one. Then reverse it (swap hoses) - you may have something blocking coolant flow to the heater core, keeping it from generating the heated air in the car. Once that's done, reattach the heater core hoses, top off coolant, and burp the system again.

The Number 1 issue with no heat, is AIR. Air can get trapped in the heater core resulting in no heat. when Cold, open the system and run it at a high idle... about 1500rpms, driving it a short distance will also work, with the cap loose so it can burp any air trapped, then top off the coolant. A pint low is all it takes.