Which heater hose goes to the head?

[Fiat88]

I bought some new heater hoses and a burp kit. I found this picture on the forum and want to know if it shows the correct way to route the hoses. Does the passanger side heater hose go to the head like that? Thanks.

[digitech]

Don't think so - it's the other one I believe.

[kilrwail]

Here's the correct routing - the right (passenger side) hose goes to the head. Ignore the labels - they were for someone else.

[digitech]

I stand corrected!

[Fiat88]

Thanks!

[RoyBatty]

My manual shows the opposite.
The hose from the pipe connected to the water pump connects to the right (passenger side) of the core, where the hot water shut off valve is.
The hose from the head goes to the left (driver side).
I'm just sayin'........
Is there a variance due to different model years?

[kilrwail]

Is there a variance due to different model years?

There could be, given all the other changes made over the years. Mine's an original '78 but the OP's may be a different year.

[digitech]

There must be because I reviewed several photos I had taken at a few car shows and they all show the pass. side hose hooked to the water pipe and the driver's hooked to the head. I also dug up an instruction sheet from Bayless (before Midwest124) that came with the new heater valve and it showed the same setup.

[ventura ace]

From the 1970 owner's manual:



Alvon

[RoyBatty]

I may have thought of another way to approach this.
The purpose of the heater valve is to control the flow of hot water to the heater core.
To do this the valve must be in the supply line from the engine. Which as I understand things comes from the water pump.
I just replaced my valve a week ago. I had to make a few small tweaks to the hard line that bolts to the flange.
I also had to reroute the control cable for the valve to have the needed length to allow for proper rigging of this control.
Now, with the engine warmed up. I can open the valve and allow hot water to enter the core. And when I select the off position with the valve, eventually the airflow out of the core cools down to ambient air temp.
It seems to me that if the lines were reversed, you would be controlling the flow of water OUT of the core instead of INTO the core. Wouldn't that possibly cause the heater core to warm up even though you have selected the off position.
I understand that if the valve is closed there is no flow thru the core. But if the output side of the water pump is pushing thru the core to the stopping point of the valve, then wouldn't heat be transferred into the core when you don't really want it?

[ventura ace]

The hard line is on the inlet side of the water pump. Water flows out the back of the head, through the firewall to the heater core, then back through the firewall to the hard line that goes to the inlet (suction side) of the pump.

Alvon

[RoyBatty]

Then mine is backwards like the picture in my manual!
Odd thing is, the core does cool down when I move the valve to the off(cold) position.
I would think the coolant in the heater core would tend to stay warm with it hooked up wrong.

[baltobernie]

That's my engine shown in the OP, and that's the way the heater was plumbed when I got it The heater works fine.

La dolce vita

[124ADDHE]

It really makes no difference, either way will work exactly the same; a bit of heat can conduct its way into the core from either pathway. I do find that the best alignment is with the passanger-side line hooked up to the head. I did read however that a bypass would be nice for when the heater matrix is not active so that there is still good flow from the back of the head, to the pump - has anyone done this ?

Keith

[RoyBatty]

Just to show I'm not making this up.
EDIT: Ahaaaaa!! I just noticed they refer to the valve as the "inlet water flow control valve" !
Neener neener