Heater hose routing

[Honky Kong jr]

It has no valve in either hose to core. I also have a pre drilled t-Stat that's suppose to let it bypass. I think I need to put a regular t-Stat in. It wants to run a little warm when idling. To much circulation.

It's gotta spend a little time in the radiator for heat dissipation. Not to much or saturation occurs. Then you get a whistle.

 

[4WDKC]

It has no valve in either hose to core. I also have a pre drilled t-Stat that's suppose to let it bypass. I think I need to put a regular t-Stat in. It wants to run a little warm when idling. To much circulation.

I dont think this is your issue, you would have to have large holes to even get close to this.
This is the tstat I am look at for my vette because its warmer than i like https://www.summitracing.com/parts/emp-300 only complaint from multiple users is it takes forever to warm up.

 

[gpmorgan]

T

I dont think this is your issue, you would have to have large holes to even get close to this.
This is the tstat I am look at for my vette because its warmer than i like https://www.summitracing.com/parts/emp-300 only complaint from multiple users is it takes forever to warm up.

That's the one I have. I didn't seem to have a problem with it heating up. I've had it in since Feb. I'm going to get a radiator shroud with 2 elec fans. I have a large 3row alum rad. They make a shroud with fans for it. Let me know how the stat works for you.

 

[Ilike55s]

Hey Folks,,,hoping I can resurrect this thread as I'm a bit flustered!! I replaced the 305 in my 82 Silverado with a 454. Bought a new water pump that has TWO 1/2" ports at the top of pump. (The two ports are at different sections of the pump) I hooked one of the WP ports to the 1/2" port on the Front port of the intake and the other 1/2 WP port to one of the heater hose. The other heater hose went to a 1/2" port at Top of intake. There is a 1/2" port on radiator that I plugged (mistake?) Started the engine and after a bit I think I could hear a water hammer in engine so,,I shut it down quick.
What did I do wrong?

 

[Dave M]

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3/4" to the radiator, 1/2" to the manifold

 

[dsteelejr]

Hey Folks,,,hoping I can resurrect this thread as I'm a bit flustered!! I replaced the 305 in my 82 Silverado with a 454. Bought a new water pump that has TWO 1/2" ports at the top of pump. (The two ports are at different sections of the pump) I hooked one of the WP ports to the 1/2" port on the Front port of the intake and the other 1/2 WP port to one of the heater hose. The other heater hose went to a 1/2" port at Top of intake. There is a 1/2" port on radiator that I plugged (mistake?) Started the engine and after a bit I think I could hear a water hammer in engine so,,I shut it down quick.
What did I do wrong?

I've been wondering what is the correct routing, too. My problem is my heater core barley gets warm. I put a new heater core in and it didn't get any better. The hoses to the heater core barely get warm, which tells me hot coolant is not flowing to it. I have a 1980 K25 and 1973 C20. The problem I have is on the 1980, but I consulted the GM factory service manual for the '73. I doubt much has changed with the heater hose routing over the decades. Here is what it has to say:

Heater hoses are routed from the water pump and thermostat housing (radiator on automatic transmission vehicles) to the core inlet and outlet pipes as shown in Figure 7. Hoses are attached at each end with screw type clamps.

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[TubeTruck]

I believe you should have a 3/4 port and a 5/8 port on the heater core. The 3/4" port goes to the radiator and the 5/8" port goes to the intake at the thermostat.

The BBC engines have a port at the front of the manifold that goes to a port on the top/back of the water pump. Some people do not install this hose and others do. I know my EFI 454 came with it so I plan on putting it back in. Some people that have not installed this hose have had overheating issues and after installing it their overheating issues went away.

If you don't have enough heat make sure your HVAC door is opening all the way.

 

[dsteelejr]

I believe you should have a 3/4 port and a 5/8 port on the heater core. The 3/4" port goes to the radiator and the 5/8" port goes to the intake at the thermostat.

The BBC engines have a port at the front of the manifold that goes to a port on the top/back of the water pump. Some people do not install this hose and others do. I know my EFI 454 came with it so I plan on putting it back in. Some people that have not installed this hose have had overheating issues and after installing it their overheating issues went away.

If you don't have enough heat make sure your HVAC door is opening all the way.

I checked the flaps when I replaced the heater core. Everything worked fine. The heater core hoses were barely warm so I knew hot coolant wasn't traveling to the heater core.

When I replaced the engine I routed the hoses the way they were before. The difference is that previously there was an electric block heater inline and there were Y fittings and whatnot. I removed and didn't reinstall the block heater. The bypass from the water pump to the front of the intake was previously used so I hooked it up the way it was before. Since the pumped coolant is going to follow the path of least resistance I think it was simply bypassing there instead of going to the heater core. I plugged one of the ports on the water pump and the port on the front of the intake and ran the 5/8" hose from the water pump port to the heater core and return it with 3/4" hose to the top of the intake. It gets plenty hot now.