1974 620 Coolant hoses and the heater control swtiches

[Richie]

Hey, 

 

So I am using a weber carb and need help with connecting hoses. I dont currently have a picture but I will try and be as specific as possible. 

1. There is a coolant pipe under the fuel pump next to the lower rad hose, (not the hose that connects to the fire wall and that elbow fitting) near the alternator. Where does that connect?

2. There is a fitting on the thermostat housing, next to the temp sender, and old egr sensor, where does that connect?

3. There is a fitting on the intake manifold location it is kind of under the carb, where does that connect? 

 

And lastly, if anyone knows how the damn metal wires that control the heater switches in the cab connect, please share. Thank you. 

[datzenmike]

All three are connected. The one under the carburetor goes to the thermostat housing where the fitting there joins it at a metal Y pipe. It then goes down the front of the engine to the lower radiator hose and joins it at the inlet to the water pump.

 

 

 

The Y is a metal pipe. Short lengths of hose connect the top left to the thermostat housing, top right to the intake and the bottom to the lower rad hose. Rubber hose and a T fitting will work but the pipe is better for protection.

 

When working, water flows from two outlets on the side of the head into the undersides of the two intake runners and exits beside the carburetor. This warms the intake air when it is cold and draws away heat in extremely hot weather. The outlet at the thermostat helps displace the otherwise stagnant water around the thermostat. The thermostat thus opens immediately as soon as the engine is warmed up rather than much later because the thermostat is surrounded with still cold water. Both these outputs are routed down to the inlet to the water pump. 

 

 

[Richie]

1 hour ago, datzenmike said:

All three are connected. The one under the carburetor goes to the thermostat housing where the fitting there joins it at a metal Y pipe. It then goes down the front of the engine to the lower radiator hose and joins it at the inlet to the water pump.

 

 

 

The Y is a metal pipe. Short lengths of hose connect the top left to the thermostat housing, top right to the intake and the bottom to the lower rad hose. Rubber hose and a T fitting will work but the pipe is better for protection.

 

When working, water flows from two outlets on the side of the head into the undersides of the two intake runners and exits beside the carburetor. This warms the intake air when it is cold and draws away heat in extremely hot weather. The outlet at the thermostat helps displace the otherwise stagnant water around the thermostat. The thermostat thus opens immediately as soon as the engine is warmed up rather than much later because the thermostat is surrounded with still cold water. Both these outputs are routed to the inlet to the water pump. 

 

 

I looked up the diagram for before this post, and this is where i am confused. On the thermostat housing, before I rebuilt everything, the connector was not a Y connector like you are describing. It was a single port outlet. So what you are saying is that I need to get a Y pipe connector for the thermostat housing and connect one end to the intake, and the other to the lower rad housing where that inlet is. Thank you. 

 

Waaiit a minute, now I am curious. How does coolant not get into the intake from the lower rad housing through the thermostat housing to the intake?

Edited November 25, 2021 by Richie

[datzenmike]

 

The water pump draws water in and pushes it into the block. There it travels up into the head. From the head....

 

2 hours ago, datzenmike said:

When working, water flows from two outlets on the side of the head into the undersides of the two intake runners and exits beside the carburetor.

 

The outlet at the thermostat helps displace the otherwise stagnant water around the thermostat.

 

Both these outputs are routed down to the inlet to the water pump. 

 

 

 

[Richie]

39 minutes ago, datzenmike said:

 

The water pump draws water in and pushes it into the block. There it travels up into the head. From the head....

 

 

That is some crazy engineering. Thank you. I am gonna find a Y pipe connector and get the hoses all connected. 

[datzenmike]

Excellent. Some thought went into this thermostat by pass and the intake coolant passages that makes it run better during and speeds the warm up when everything is cold. Why not take advantage of it? A 'T' fitting will work with hose barbs on the ends.

 

 

 

[Richie]

On 11/25/2021 at 6:50 AM, datzenmike said:

Excellent. Some thought went into this thermostat by pass and the intake coolant passages that makes it run better during and speeds the warm up when everything is cold. Why not take advantage of it? A 'T' fitting will work with hose barbs on the ends.

 

 

 

Hey. So i went through my part box and found this metal pipe that run from the radiator outlet, to the intake with a connector that lines up perfectly to the thermo housing outlet. See if no one touches my stuff I dont have to stress about.