I'm contemplating installing a screen filter on the inlet side of the coolant flow through the water heater in the engine compartment. Anyone know which is the IN and which is the OUT?


Thanks, Bill

 

The IN is always the lower spigot on these systems.

The OUT is the upper spigot.

 

Except that mine on the XJ6C is an inner and an outer. Not an upper and a lower.

 

HOT water/coolant ALWAYS travels from the water pump to the valve and on to the core as shown.

(';')

 

I posted this question a while back. Lot's of good answers. search "coolant flow through the heater core? "


hopefully helpful
geneo

 

I always flushed my whole system about every 3 years including the
heater core using a cleaner and so far its working fine after 35 years.

Walter

 

After doing a bit of research I found out that with a GM TBI engine ,.. the coolant flows from radiator bottom hose through the water pump.. then through the engine,..under the TBI unit where some exits out of the heater hose connection (rear of intake manifold) goes into the heater valve ..through the heater core...out of heater core to radiator. Also the TBI intake manifold has the rear water port (head to manifold gasket) blocked off with restrictor plates. Not all SBC are the same. With the TBI engines the water pump does NOT flow coolant out of the water pump water fitting to the heater valve. Rather coolant travels through the engine and exits (some of it) from rear coolant outlet on manifold to heater valve through the heater core and drains forward through a long hose to empty into the radiator. The bulk of the coolant returns through the thermostat to the top of the radiator. Restrictor plates are critical. So SBC are not all the same - depends on application / year / vin number.