Reason for slight heater core flow?

[CyFi6]

Well I was thinking about throwing a manual shut off valve for the heater core into my truck for the summertime just to keep any chance of extra heat out of the cab. I remember that in the Supra (and probably other vehicles) the heater control valve never shuts off coolant flow 100%, and leaves a small opening for coolant to trickle through at all times, even with max AC on. I always wondered why exactly this was needed, and if anything can/will be damaged if heater core flow were completely halted. Only thing I can really even imagine would be that stagnant coolant in the heater core could somehow speed corrosion, but that is kind of far fetched and I don't have any evidence for the reasoning, just a pure guess.

 

[hvyman]

Think it's more a flow thing so heat doesn't build up in any one spot more than another or create a wall with it no where to go.

I'd just leave it. It's extra cooling capacity.

 

[te72]

I'd just leave it. It's extra cooling capacity.

It's also in Arizona, where any additional heat in the cabin is quite unnecessary.

I personally never worried about it, if your AC is working well, you shouldn't even notice it. Tint your windows if you haven't already, I know of a really good place in Glendale that has done 3 of my cars now...

 

[SupraPieces]

it was probably made that way so that you wouldn't have stagnant water sitting in your heater core and rot it out... flow=healthy

 

[IJ.]

it was probably made that way so that you wouldn't have stagnant water sitting in your heater core and rot it out... flow=healthy

"should" be a coolant mix so there's little chance of it "rotting" more a case of it reduces the chances of an air pocket forming.