Which way is the water circulating in the radiator in a 2001 Ford Powerstroke. Is it "fed" from bottom to top, or is the inlet on the top? Best regards from Norway

There are two large hoses attached to a car radiator. The top one is usually attached to the top of the engine at the outlet of the thermostat housing. This is the return line to the radiator. The lower large hose is usually attached to the water pump inlet. This is where the cooled down coolant is circulated back into the engine. If you have an automatic transmission, there are likely two smaller hoses attached to one side, one on top and one on the bottom. These are cooler lines that attach to the transmission to cool the transmission fluid.

One exits the thermostat housing and the other needs to enter at a different point, usually the water pump.

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The water pump is enclosed on the front of the engine. The bottom radiator hose connects to the water pump inlet.
You do not add coolant to the water pump. You add a 50-50 mix of antifreeze and water into the radiator cap opening. Or you can buy the coolant already mixed with water and just pour it into the radiator.

The coolant system uses the water pump to circulate the coolant through the engine and then into the radiator via the upper radiator hose for cooling it off, and it then goes back into the engine through the bottom radiator hose. When the engine is warmed up, the coolant constantly circulates through the engine to radiator and back into the engine.

If both heater hoses are getting hot, the problem could be a stuck blend door under the dash.
If only one hose is getting hot, there is a blockage in the coolant flow somewhere.

if it is not loosing coolant, then the coolant is not circulating. Moving the warm stuff to the radiator to cool and then cool stuff back into the engine is the way it is supposed to work. bad water pump or clogged radiator come to mind first. remove the engine ends of the two large hoses from the top and bottom of the radiator and dump water into the top hose, if it does not flow out the bottom hose at about the same rate, it may well be clogged.

The most probable cause of both problems is with the replacement heads. As far as knocking goes, hard to diagnose from here - usual causes are a noisy hydraulic lifter (which, if severe, should be replaced) or a failing piston bearing or incorrect head/head gasket (piston banging on head which is very serious). Also, if the head gaskets were incorrectly installed or the wrong heads were used, you could have blocked some of the cooling water ports.

Overheating can also be caused by a blocked radiator - the system circulates the cooling water into the bottom of the radiator and the water cools as it circulated up to the top and back to the engine. A quick way to check when overheating is to CAREFULLY see if there is a hot-to-cooler temperature gradient in the radiator from bottom to top.

You need to make sure the coolant is circulating. Check to make sure the top and bottom hoses are hot and firm to the touch. If the bottom hose is not hot and firm the water isn't circulating which means the thermostat is stuck in the closed position. Also check to make sure the radiator isn't clogged or doesn't have to many crushed fins that prevents the air from properly cooling it.

dear friend:i think we should start with pressure testing the system for water leaks,if there is leaks you will loose pressure,if you reach working temp feel the top and bottom radiator hose,they should be the same temp,if not then the thermostat is faulty,if you got poor circulation then it can be the waterpump or the radiator is blocked,check airflow threw the radiator,check radiatorcap pressure,

When engine is cold, take out the thermostat. Put back everything add water as needed to the radiator, leave the radiator cap out. Start the engine be careful stand in front of the radiator and where the radiator cap goes watch if the water is circulating rev it slowly and the water should circulate faster. If it is not circulating the radiator maybe clogged, inside the cylinder head where coolant circulates might be clogged or the water pump is not working.

Ok, I will ty to help ya.  This is pretty simple.  First pop your hood open.  Make sure your engine is cool or you can and will get burned!!! Take the cap off of the radiator.  Under the car on the bottom side of the radiator, to the passenger side I believe is a plug.  Get yourself something ***Clean*** to hold the antifreeze in.  It has to hold a few gallons.  Make sure it is clean if you want to reuse the antifreeze.  If you can not find a plug, take the bottom hose off.  Drain the antifreeze.  Next, look on top of the radiator.  There should be a big hose going from the top of the radiator to the engine.  Follow it.  It should be connected to a metal water inlet that is bolted to the engine.  Take that end of the hose off.  Unbolt the water inlet from the engine.  inside is your thermostat.  ***Make sure you note which way the thermostat sits in there.*** As is you install the new one backwards, it will not work.  After you have your new thermostat in place, use some sealant and place the inlet back on the engine.  Tighten the bolts down.  Reconnect your upper hose.  Put you bottom hose or drain plug, whichever you used, back together.  Refill your radiator with antifreeze.  Chances are it will not all fit.  you may need to run your engine for a few seconds to get it circulating.  Put you cap back on and drive the car a few miles to get it warmed up.  Come back and let the car cool off.  Open the cap and make sure it is full and you are done.  I know it is lengthy, but it is pretty simple.  Hope it helps and please don't forget to rate!