The Stovebolt Site Forums The Shop Area Interiors Heater water flow 1949 3100

I have had the heater core cleaned the heater cntrol valve rebuilt, but I can't get any heat out of the heater. The hosees get hot going into the heater control valve and out of the valve, the other hose is cold. I think the heater is air bound. ANY IDEAS. :confused: :confused:

I know you didn't reverse the hoses. So, you are sure the valve is completely open and letting more than a trickle through? Disconnect both hoses in front of the valve and everything, fab up an adaptor to a water source like a regular water hose. Put a bucket on the outlet hose and see what happens.

bill1949,

I'm just guessing, but if the valve is 'thermostatic' it must be direction sensitive to water flow.

If this is true (my guess), then maybe you have the hoses reversed.

Stuart

bill1949,

I have enclosed a link to a picture. You can scroll forward and backward to look at different pages. This shows hose routing and might help.

http://chevy.tocmp.com/accessories/1951am/51aim38.htm

Stuart

Mine had a plastic plug placed inside the heater core supply hose at the pump. Ya never know what you're gonna find. Besides, I don't need no stinking heat!

atomarc

From what I see in your pictures I have the hoses in the correct places.
it seems like I can't get the heater core full of coolant.

bill1949,

It appears to me that hose "B" would be considered the supply hose. It comes out of a nipple on the water pump, through the heater core, then on to the thermostatic valve and completes the trip ending up in the thermostat housing, on the engine side of the thermostat.

The water pump is always trying to push the water through the heater core. It can only be stopped by the valve, or a thermostat that hasn't opened yet.

The heater core probably wouldn't 'air lock' as it has the positive pressure of the water pump behind it.

The heater valve must be turned ON to allow the water through. It's a open system except for that valve and the thermostat...you could always just bypass the valve and see what develops.

If you print the picture, it becomes much more readable and clear. Double check the hoses and give it another try...it's a pretty straightforward deal.

Stuart

Atomarc, I looked at the picture you provided and am not trying to be a "smartie". But I always thought the heater control valve was suppose to be in the supply line to the heater. Am I wrong on that? It sure looks otherwise in the picture. Thsnks

beltfed,

A "smartie" huh!. I am only going by the little picture I linked...having never dinked with one of these. The valve in question isn't a simple ON/OFF valve (I think). There is a small bulb/capillary tube affair that sits in the cab and signals the thermostatic valve to open or close to some degree...a crude climate control.

This valve needs to be on the downstream side of the heater core so the core is always charged with 'hot water'. The valve is adjusting this gradually...allowing more through to bring the heat up and closing to cool things down.

This is how I assume it works, but I have been know to be wandering in the fog before.

Stuart

I'd say Stuart's right, FWIW - there isn't really a 'supply line', the heater flow is just a loop - the valve restricts the flow in the loop so that the water that goes thru the core is slower/faster

if bill1949 has freshly rebuilt parts, the right hookup, both hoses on the valve hot and the one from the core cold, I'd suspect that the freshly rebuilt core has a solder plug preventing flow

the test would be simple - remove hose at point C and plug that at the engine, see if water comes out the hose

if you can make up a simple fitting you can also take both hoses off the core and put yer garden hose to either core tube and see if water flows thru it ..... case closed

Bill

Having just removed mine this week, I'm certain it is hooked up so that the flow is from the water pump to the control valve, then into the core. As explained elsewhere, I think by Red58, you want the valve on the supply side. This keeps the core from always being "full on" with pressure. My apologies to the original poster if I got it wrong.

I admit not yet fully understanding the function of the capillary tube except that it is some type of crude "climate control." New valves sold at parts houses do not have this feature. (Draw your own conclusions.) However, being isolated from the hot supply would only increase flow.

I'll keep watching the thread. I'm learning from reading.

Bill

Atomic,
As always, your point is well made.
Beltfed

TxLaTx,

I think you are correct. The water exiting the thermostat housing, being heated by the engine, and not yet cooled by the radiator, would be the hottest. This would be the supply (sorry Red) for the heater. I had it backwards! From top of engine, through valve, through heater core and back into engine via waterpump (negative pressure side).

You can't keep a good Atomic down for long!

Stuart

Is it too late to change my mind? I think the pressure, or supply side of the 'loop' comes from the nipple on the waterpump and follows the route shown in the GM picture...how could that be wrong, right!

It just makes more sense to me that the normal flow of water would always be OUT of the pump, from the bottom of the engine to the top, and not bass-ackwards from the top back to the pump.

It looks like I am asking AND answering my own questions here...a one man thread!

Stuart