Pl510, does it matter which way heater hoses are connected?

[Dolomite]

Edit: I found a oic of my old two door’s engine bay, and confirmed with a friend.

[MikeRL411]

The heater inlet ought to be on the pipe that has the shut off valve.  If the core springs a leak and you have the inlet on the non valved connection you will flood your car and probably ruin your carpeting.  Other than that, be my guest !

[tr8er]

Yeah, as Mike said, doesn't matter

[datsunaholic]

If the heater core leaks it won't matter which end has a valve.  Not with a system pressurized to 10-15psi (or more).  Even if the non-valved side is on the suction side of the pump- because the pressure doesn't instantly go away when the engine is turned off... but it does equalize in the entire system.

[MikeRL411]

If the heater core leaks it won't matter which end has a valve.  Not with a system pressurized to 10-15psi (or more).  Even if the non-valved side is on the suction side of the pump- because the pressure doesn't instantly go away when the engine is turned off... but it does equalize in the entire system.

 

But, with the input on the valve side you can shut the valve off.  If the valve is on the outlet and you shut it off you increase the leak flow rate.

[datzenmike]

I think what Doug is saying is the pressure is the same anywhere in the cooling  system.

[MikeRL411]

I think what Doug is saying is the pressure is the same anywhere in the cooling  system.

 

So pop the lever on your Stant radiator cap.

[datzenmike]

That would slow down a leak on a hot engine. Might even stop of the hole is very small. When cold it would still siphon out until the coolant level is at or below the leak.

[datsunaholic]

So pop the lever on your Stant radiator cap.

 

That essentially releases the pressure in the entire system, as it's now no longer a closed loop.

 

The pressure in the system is not created by the pump.  Its caused by heat. 

 

My point was, however, that if you have a heater core leak it doesn't matter where the valve is.  Unless you isolate the heater core entirely, which requires TWO valves, you'll still end up with a wet floor.