Heater core water flow question.

[tinman_72]

Does water flow through the heater core at all times or is it somehow bypassed when the heat is off? (The question pertains to a '93, by the way.)
Edit:
Actually, more specifically, does water constantly flow through the heater hoses? I want to add a mechanical temp gauge and I was thinking it would be easy to find another tee like the one that holds the temp sensor in the heater hose.

 

[Fast Fords]

i do believe it is constantly cycled throughout the entire cooling system during operating of the vehicle. I guess the only way heat is brought into the cab and the coolant cooled is when the blendoor and heater fan is open/on.

 

[RangerFabWorks]

yes hot water is always cycled through the heater core. the way you get the heat up to the truck is by opening the blend door, and turning on the blower motor, this allows the fan to blow heat up into the ducts. as for hooking up a mechanical gauge to it. i wouldnt trust it. cause it will only send up the hot water when the thermostat is starting to open. just run it to the block as was intended. itll read way more accurate. hope this helps, dave

 

[Mark_88]

OK...I just looked at my setup that may or may not be different from other engines...but one of my lines to the heater core comes off the connector that houses the T-stat...and the other comes from lower down on the water pump...without fully understanding the actual flow of the fluids I would think that the T-stat remains closed keeping the hotter fluid from exiting the engine until it is at operating temperature...once the T-stat opens the hot fluid goes to both the rad through a larger tube and the heater core...

I'm going to try to find a flow chart for this because I may have my lines either mixed up or backwards...which wouldn't surprise me at all...

 

[RangerFabWorks]

mark you are correct the line off the t-outlet is the inlet on the heater core, and the return goes to the water pump. that is why i wouldnt hook a gauge up the way this guy wants to. your gauge wont read anything untill the t-stat opens, then the gauge is gonna bounce up. so i would just connect the gauge to the block.

 

[Mark_88]

Thanks for the confirmation on that...

I have that line going to the right side of the heater core, and it branches off into the head through the intake manifold...this is where I may have things mixed up...thinking that the outlet from the heater core should actually go to the intake because this fluid should actually be cooler than when it goes into the heater core...especially if there is airflow through the heater core...

I copied my current setup from a Mustang in the junkyard...so it could be wrong...does anyone have pics of how this should go so I can make any necessary changes?

I think it would help both the OP and others...TIA

 

[RangerFabWorks]

on my ranger, the inlet came off the top of the water pump, then the outlet branched into the head with all the weird pipes running from the head, the exhaust manifold and everything in between. so it sounds like yours is correct. im a chevy guy so i guess thats why we usually have no heat.

 

[AllanD]

A temp guage in the water line to the computer provides an accurate point for measuring temp

Lets be real guys if it's good enough for engine management it's good enough
for a guage.

The HEater core flow path is constant flow
the tap for the heater core bypasses the thermostat
and returns the flow to the pump

No coolant flows through the radiator until the T-stat opens

If I wanted to add a guage that's where I'd put it.

but in truth you really only need to know "cold, normal and Hot"
Knowing the actual exact temp isn't useful to most people.

Personally I could care less, I know where my factory temp guage "lives"
and if it's somewhere else I know I have a problem.


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