Gen 1 3.0 v6. I pulled the lines at the firewall and with the temp slider to the warm side can pump water through the heater core so both it and the valve can flow, the supply line from the engine delivers coolant out of it when cranked briefly to check flow. I also squirted with the water hose into the lines going back into the engine. The supply line that goes into the heater valve would take water in and raise the radiator level. The return hose from the heater core back to the engine didn't take any flow or raise the radiator level that i could see. Thats a tight spot back there , i see one is flanged with two bolts and the other clamped to a pipe.
Can anyone enlighten me as to where these two are going? There isn't a hidden manual cut off valve i don't know about is there?
Thanks for replys
Mike

Maybe corrosion blocking the return? No other valves besides the one on the core.

I'd run a small diameter coil spring down the blocked hose, or maybe a flat plumbing snake, or hit it with some air pressure. Is it possible you are deadheading against the thermostat? Try removing it and hitting the hose with hose water again. The FSM is spotty on which hose is which. The clamped hose should be a direct flow off the water pump. The flanged hose connection looks like it comes off the lower intake, but I can't remember the exact water routing. Been too long since I've been in there.

Any body got an upper intake off and could shoot some pics? I'm pretty sure the flanged connector is the return side, but not sure enough to make any definative comment.

is this what your looking for ?

Thanks, but no. I need the lower intake that bolts to the head and has the t'stat on it on the front and may have the two bolt water flange on the back. Appreciate the try, though. Sorry I wasn't clear enough.

i got that too,here you go.

Thank you, sir. Exactly right.

OK, the two flange connector goes straight into the heads thru the lower manifold, as I thought I remembered. The water pipe under the lower mani goes straight to the water pump, IIRC to the pressure side of the pump, but that may be wrongo. I doubt either path is blocked in the metal. This leaves a blocked hose, perhaps from an internal collapse. Replace the hoses.

Ok I found what looked like some radiator seal down in the clogged pipe. I've got a leak at the heater core and will start a new thread if i don't turn up anything in the search.
Thanks
Mike

Well I got minimal heat at first and got back in there and dislodged of all things a friggin cork that had been jammed into the return line....
just goes to show you never know what a previous owner may have done .... <img src="/forums/images/graemlins/confused.gif" alt="" />

These pics might help as well. They are off a 1993 gen2 3.0 12v V6.

I presume it will be the same.

The red and blue goes to the rear matrix.

The red in the top and the red in the bottom pic is the same.

The long pipe on the intake plenum goes to the heater core's open pipe on the top picture.

Hope it helps