Bypass hose

[ss454elco]

I'm putting a 454 in my 84 K10 and want to eliminate the bypass hose because the hose is stressed at the water pump nipple. The nipple on the water pump sits at a 45° angle which doesn't line up well with manifold nipple. Everything I've read says you need it to prevent hot spots or air pockets and that BB's are prone to cavitation. But doesn't running the heater hose off the intake do the same thing? Some say drill a couple 1/8-3/16" holes in the thermostat but that won't flow as much as the hose will. Looking for possible solutions or input from others who have dealt with this. Thanks.

 

[75gmck25]

On many squarebody trucks the heater return hose runs to a fitting on the radiator instead of the water pump. When I remove my radiator cap I can look in and see that this hose is really flowing a lot of water.

You can buy a thermostat with a hole in it, or just drill yourself, but this is mostly just to prevent an airlock. AFAIK, it does not replace the heater hose bypass.

How about using a water pump fitting that has a different angle, so the heater hose routing is better?

 

[ss454elco]

I did end up getting 1/2" MPT x 5/8 hose adapters at Home Depot that were shorter than normal water pump hose fittings. I shortened the hose barb portion which allowed better alignment. I'm just wondering why the hookup to the waterpump. Is it just to have coolant flow when the thermostat is closed? If that's the case, doesn't coolant flow from the same passage as the thermostat through the heater core do the same thing? (Assuming there is no hot water shut off valve in the hose going to the heater core).

 

[fast 99]

Bypass is designed to circulate coolant before thermostat opens to reduce hot spots. Might be other reasons as well.

 

[matt4426]

I think the heater core coolant circuit does the same thing as bypass hose on BBC.

 

[matt4426]

See picture:

The heater core pressure line comes off upstream of the "closed" thermostat and allows coolant flow before the thermostat opens.

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[Keith Seymore]

I haven't run the bypass hose in forever.

Just a couple 1/4" holes in the thermostat.

K

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[ss454elco]

matt4426, that's exactly what I was thinking. Don't understand why the factory would run hot water from the manifold right back into the motor, (albeit mixed with cooled water from rad) unless it was a form/function/production cost thing. I'm wanting to remove hot coolant and intake only cooled coolant. I like what you did with your hose to the heater core. Much cleaner than up over the valve cover from the manifold. Thanks for including the picture.

 

[Fastduramax]

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[Fastduramax]

That is actually a 90 degree molded hose I found and shortened it quite a bit, the stainless fittings I used are so close together a straight piece of hose kinks…