propper routing of heater hoses

[andyr354]

This is on my 70 with out AC. What port should the heater hoses go to, and what is the direction of flow. I assume out of the intake and back into the water pump (this is a short shaft water pump). One hose is conected to a bung on the front water passage on the intake, other hose dumps right back to water pump.

Also I would like to add a manual shutoff valve to the system to shutdown some inside heat on warm day drives.

[Blue Beard]

Are you still using the A\C?

[COBALT]

Yep, that's right. Just remember that the fitting on the intake (hence the size of the hose) is 5/8" standard. As you said that's the output to the heater core (bottom?). Fluid pressure forces the fluid up through the core to the output to the water pump. The input to the water pump is 3/4" (again, so is the hose).

Pretty simple. I've installed, and re-installed, and re-installed fittings, cores, and hoses on my truck so many times I think I could do it in my sleep. Normally I just get about a 3' length of both hose types, + some clamps to go with it - 4 5/8" clamps, because I usually install a flush tee on the 5/8" side for flushing. I run the 3/4" from the top of the heater core straight to the water pump. Easy. The 5/8" I cut into two pieces, run a piece from the heater core to the flush tee, and clamp them. Then I run the other piece from the other end of the flush tee to the intake. Clamp those. There - I'm done.

The only sticky parts are:

1. Getting good fittings for the intake/water pump. Most of us have a mix of metals: aluminum for intake and cast iron for water pump (unless you've gone aftermarket on your water pump as well). I've found that using the basic thin walled steel fittings you buy at NAPA (not the cheap ones in the rack but the ones from behind the counter) ALWAYS seal right and fit right. I use the liquid sealer with teflon, and let them set up for a few hours before adding coolant and starting the engine. Don't use brass mixed with aluminum and running fluid. I've also had bad results with chrome fittings.

2. The necks on the eater core can sometimes be easy to crack and cause a leak when you're putting the hoses on. They just like to bend. Therefore I use some water soluble lube (don't laugh....KY works great) to make sure they slip on without me damanging them.