No coolant flowing through heater core

I just swapped out a 1.9L engine in a 95 escort and it runs great but there is no heat coming out of the heater. I replaced the thermostat. The radiator is full. The upper hose gets hot. The heater hoses do not get hot. The guage shows just above the cold mark and the heater hose with the temp sensors is only a little warm. The other heater hose that goes back to the water pump does not get warm.

It appears to me I am not getting circulation through the heater core. I back flushed the core and it looked ok. The only other thing I can think of to check is the water pump. This is not an easy one to get to because it is behind the timing belt.

Does anyone have any other ideas on why I am not getting any coolant flowing through the heater core?

Thanks.

Do you think you got all the air out of the system. I would make sure of that before you go checking the water pump. If your engine isn't overheating your wter pump should be working just fine.

I am not sure what else to do to get the air out. There is no bleeder valve. I thought about putting in a flush T on the heater hose and then hooking a hose to it to see if that would push out the air. Not sure what else to try.

Thanks.

Make sure both radiator hoses are getting hot. If this occurs the water pump is working. Does the engine come up to operating temperature. For a while I got a lot of bad thermostats. I heated an old coffee cup of water in the microwave.
I watched them work before I put them in. If the engine is coming up to temperature and both radiator hoses are hot I would drive it for a couple of days and see if it will circulate. Some time they have to get completely full
before they work.
Some Ford trucks have a heater control valve which has to open but I don't think an escort has one,easy to check for as it would be in the heater hose.

Try just removing your radiator cap and running the car till the thermostat opens that should pull in the antifreeze and you can add more if needed and hopefully get all the air out.

that heater core is not that hard to take out asuming it's almost right under your glove box like my one i had and never will have one again. i'd take it out run little pressure of water threw it see what happens or comes out of it.another thing is when it's cold start it up take cap off see if it's circulating threw radiater.

I agree that you may need to get air out. When cool, fill the radiator to the top then close it and start the engine. As the engine warms up, continue to add water/coolant into the reservoir as necessary. If the water pump is working you should feel warmth and pressure on the upper radiator hose when the thermostat is open. Chances are that it is fine.

Continue adding coolant through your reservoir until the level holds and the gauges start reading normal temp. Once that seems ok, then check for heater operation.

Thanks for all the input. The upper hose does get hot. The problem with these cars is the heat sensor is not in the engine. It is in the heater hose. If there is not circulation through the heater hose due to trapped air or a bad pump, you don't know what the real engine temp is. I just don't want to take the chance of over heating the engine and voiding the warrenty.

I ran the car with the cap off and let it get hot. I started spurting water out of the radiator onto the engine. It does look like the water is circulating because the water I add gets mixed with the green coolant.

I am going to try again tomorrow morning.

Thanks.

You will need to have the cap on the radiator so pressure can build. Pressure is a major part of temperature control as well.
When the engine is cold, fill the radiator through the cap, otherwise when it is running fill through the reservoir. WHen the radiator needs water it will draw from the reservoir.
Also be sure the hose from the reservoir to the radiator is not damaged or clogged.

Thanks for all the help on this. I found out what the problem was when I took the water pump off. The wrecking yard I got the engine from put red caps over all the openings in the engine like vacume lines and water outlets. They put one cap inside the water pump heater hose outlet where it was hard to see. I found it when I took the pump off. (Not a simple job.) Took the cap out and put it all back together and it runs great with lots of heat. I will make sure I check all these next time.

Thanks.

good deal..you'll never forget that now will you?glad your up and running again..

scrapper1