adding a shut off valve for heater?

[skiknox]

I just replaced my heater core in the old heater on the 95 ps205 lt1 and i want to add a shut off valve where to brass barbed fitting comes off the engine. Anyone know of a threaded to hose barb valve i can use?
thanks,
Ben

[wheelerd]

Here's a pic from my MCX. Valve is just on the left of the photo above the valve cover. Return barb is down by the pulley. (Hoses are off for winterization.) I don't know the exact specs of the shutoff valve but they do exist. You can likely find one at Lowes or Home Depot.

[TRBenj]

I assume this would be so that you could turn off the water loop through the heater core, should it break again? A valve obviously wouldnt help for draining (winterizing), though some quick disconnects would.

I think it would be very difficult to find a valve with hose barbs built in. Its easy to find a proper sized ball valve with female NPT threads that can accept a hose barb fitting x NPT male thread on each end, though. Assuming your heater lines are 5/8" ID, I would grab the appropriate quantities of the following part numbers from McMaster.

5346K66
47865K23

[Ben]

No help on the valve (yet), but can i ask where is your heater located and what all outputs do you have? I'm trying to figure how to stuff one in a 94. Pictures?

[CiscoStu]

On the MCX, the valve is actually on the RETURN side of the circuit that goes to the heater core. Turning off the valve doesn't prevent water from going through the heater core, it only stops it from going back into the block. You need a fully sealed system (no leaks) for the valve to do any good.

[wheelerd]

Originally Posted by CiscoStu

On the MCX, the valve is actually on the RETURN side of the circuit that goes to the heater core. Turning off the valve doesn't prevent water from going through the heater core, it only stops it from going back into the block. You need a fully sealed system (no leaks) for the valve to do any good.

Depends where that valve is. On my MCX (pic above) the valve at the intake manifold is on the pressure side. Water circulation in the typical GM small-block (with the exception of the LT1) is: in through the bottom rad hose, through the block, up through the heads, out the intake manifold via the thermostat.

[Ski-me]

In my 94' the heater box is under the dash, wedged in by the steering column. It does look tight but it does work, too. I have 2 hoses, one to the driver's feet and the other just to the left of driver, between walkway to front.

[CiscoStu]

Wheelerd, you can see that the non-valve side is on the water pump... It's a push, not a pull.

I went through h*ll with my local dealer when I poked a hole in my heater core. I knew it had a hole in it when I de-winterized the boat, so I called and asked if turning the valve OFF was all I needed to do. The mechanic said, "Yup", turning the valve off prevents water from going to the core. WRONG! With the valve off, the heater core was leaking water to the tune of about 1-2 gallons/minute. Thats a lot of water going onto the carpet and down to the bilge.

That valve will only stop water going to the heater core if it's a sealed system...

[wheelerd]

I beg to differ. See http://wiki.answers.com/Q/Coolant_flow_v8_diagram
That's why the return line from the heater is sometimes Y'ed into the raw water pump supply line so that it draws better and provides better circulation at idle.

[skiknox]

mine feeds dead in the center right below the k&n filter, not trying to use for winterization just to shut water from always circulating through core when not in use.