Does it matter which direction I have the coolant flowing through the heater core? I can't think of any reason why it would matter, and as of now I have it flowing the opposite way from stock and it seems to work fine.

I picked up a vacuum operated bypass valve from a caravan and the only way to really get it to plumb in and be oriented right is to have the coolant flowing the opposite direction from factory.

Thanks, Aaron

 

If the two pipes are the same size.......you might even get you heater to work a little bit better (do to reverse flow losing and lifting the crud out of the bottom of the heater core.


Flash.

 

Should be fine. Just check the condition of the coolant periodicaly incase the reverse flow knocks some junk loose in the heater core.

 

People used to do that on purpose, way back in old timey days.

They would change hose directions every year as a part of preventive maintenance.

 

What would be the benefit(s) of a "Bypass" type of valve in this application?

 

Would help keep heat out of the cab in the summer.

 

The standard/OEM cut-off valve accomplishes that, . . .. or am I missing something?

 

True.

Thought you were talking about replacing that one with a bypass valve. Same result either way.

 

I've heard that the valve in our trucks can stop closing completely over time and will still allow some coolant flow through the heater core. Some people have reported an increase in cool air from the AC after installing a bypass valve as it doesn't just shut off the coolant from the heater core it still allows the coolant to flow, just not through the core.

I also put one of those kits from cummins that replaces the freeze plug in the back of the head and allows coolant to flow out the back of the head.

 

I installed a "T" with a 2lb. check valve and a manual shutoff valve south of that in the heater circuit after I found it impossible to find the correct heater valve for my '71 Chrysler. Works great. Valve open in winter, water flows through the entire circuit, including the heater core. Valve closed in summer, water flows only through the coolant filter portion of the circuit.

 

On a new heater core it won't matter as much, but on your 20 year old unit, it will. Flow in is the passenger side hose, out is d-side or closer to engine. If unsure, just follow the hose from the t-stat area to the core and the hose where it returns the coolant to the block.

 

Why ??

Is there an internal design reason for this ??

 

Yes, our heater cores are designed like a radiator with an inlet and outlet. In via the top, out via the bottom. Hook it up the opposite way the old core could be plugged or at the very least have much more resistance that way. Take a new heater core, shoot compressed air through each tube. You should be able to hear a change in the tone of the air, indicating a higher resistance to flow one way. At least in my experience.

 

Well so far with it being hooked up backwards the heat has been working normal in the mornings. So I think i'll be leaving it like it is unless someone has had an experience that indicates this will be bad.

Thanks for everyone's replies.

Aaron

 

Last time I looked, the heater cores were of the cross flow design.