Heater core

[rwljpl]

So what goes on the water pump where the hose is currently?
And what do I do with the hose currently on the manifold next to to the thermostat/big hose?

 

[Powerhouse Ranch]

79 k10, small hose to intake fitting, big hose to water pump, been this way at least 30 years. Still cooks you out of the cab in -30

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hmmmm very interesting

 

[Shorty81]

l would think that to maximize your heater temp, you need to move the hose from the water pump to the plug location on the intake manifold to the left of the t'stat housing.

Dave is right. Move the hose from the pump to the intake. I made this mistake myself and had no heat also.

 

[BigDaddy72]

On sbc I’ve always ran them to the intake and plugged the water pump.

Honestly I never thought of doing it differently than that.

It has always worked.

Also sounds like you may have some air pockets in it too.

The hose switch to the manifold is easy and I think it’s either 3/8 or 1/2” npt fitting for the pump to plug it off. (I don’t remember which one sorry) Easy peasy.

 

[Blue Ox]

The lower radiator hose is the suction side, so your core return is going to suction, but the lower hose goes the the same part of the water pump that your feed hose is going to. Basically it looks like you've got both sides of the heater core plumbed to suction.

So it all just sucks.

 

[PrairieDrifter]

So I have a magic truck then? Or what

Edit- I'm keepin em coming! Missed a post lol. I now see he has one going to the rad and one to the water pump.

 

[rwljpl]

I want to make sure I’ve got this right -
1. Disconnect hose from water pump and plug that hole on water pump
2. Connect that hose to manifold as in picture

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[PrairieDrifter]

I want to make sure I’ve got this right -
1. Disconnect hose from water pump and plug that hole on water pump
2. Connect that hose to manifold as in picture

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If that's the smaller hose and the bigger hose is going to the rad then yes you are correct.
Also those fittings should interchange with each other.

 

[rwljpl]

What sealant do you recommend for these plugs? They’ve got a gray sealant but I don’t know what that is. I plan to do the work this weekend.

 

[Bextreme04]

What sealant do you recommend for these plugs? They’ve got a gray sealant but I don’t know what that is. I plan to do the work this weekend.

I usually use a Teflon tape or a liquid PTFE with Teflon sealant. If you are using tape, don’t be shy with it... biggest mistake people make is using just a wrap or two.

 

[PrairieDrifter]

I use the white tephlon paste.

 

[Octane]

79 k10, small hose to intake fitting, big hose to water pump, been this way at least 30 years. Still cooks you out of the cab in -30

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My 77 is the same way,big hose to pump and smaller to the intake.Been that way since 1977

 

[Octane]

Yep, has coolant in the core but no flow, explaining the warm air and slightly warm hoses.

The big hose should go(marked in blue) either to a nipple on the radiator, or to a hose barb at the top of the water pump.

The smaller hose should go to a hose barb fitting, that is straight over to the passenger side of the intake, from the thermostat housing. (Marked in green)

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I believe you are right,when the hose hooks to radiator the other hose hooks to intake.

 

[Turbo4whl]

What sealant do you recommend for these plugs? They’ve got a gray sealant but I don’t know what that is. I plan to do the work this weekend.

My reply might be too late, but I would not use teflon tape. More reasons than @Bextreme04 stated but I'll save that unless someone asks.

PST pipe sealant as stated is good. My choice is #2 Permatex, but I'm sure someone would disagree. Also, I would not use a silicone sealant unless the package specifically calls out, good for antifreeze, like an anaerobic sealant. For a anaerobic to work well, both metal connections must be clean. The #2 Permatex will work on rusty threads or threads with old sealant still present.

 

[PrairieDrifter]

I believe you are right,when the hose hooks to radiator the other hose hooks to intake.

The small hose always goes to that intake fitting, I've found. Then either the water pump fitting or rad for the big hose.