boiling water out of coolant reservoir, thermostat good, water pump good. Water not circulating through engine.

 

First of all what kind of vehicle are you talking about? Need to know year, model, engine. How do you know that the water pump and t-stat are working properly?

 

Thermostat in correctly ? All air purged outta system ?

 

89 Cherokee 4.0, check the thermostat and it opens and closes with temperature, took out water pump, seal, shaft, impeller and baring are all good. Everything working but not getting water circulation

 

not an expert but check the lower radiator hose. there should be a spring in there that keeps it flowing. otherwise, the system might pinch the hose closed when operating at temp

 

Please explain how a hose will collapse when the cooling system is pressurized.

 

Umm no. Older ruber hoses contained springs to prevent kinking. Newer hoses do not need springs due to how they are made. 99% of hose springs have rotted away and are not available anywhere.

Only reason a lower hose will collapse is because the radiator is completely clogged making the water pump create a vacuum

 

thanks for correcting me. this was what I had been told.

 

The water pump wont create a vacuum and collapse a hose. The water pump is not a positive displacement pump. When the t-stat is closed, there's no flow thru the rad because the closed stat has plugged flow thru the rad. The entire system is pressurized even when the stat is closed.

 

Do you have coolant bubbling out of teh coolant bottle?

If so, replace the cap with a Napa 703-1396. Pressure must not be allowed to escape otherwise an overheating condition will result.

 

Also make sure you have the correct water pump, i.e., spinning in the correct direction.
Regarding the coil -in-the-hose, we just had a long thread not too long ago and the bottom line was that the coil is placed inside the lower hose to assist in the assembly process in the factory. Find the thread for additional details. Interesting read.