Coolant Leak

Cracked head or blown head gasket. You could crank on the head bolts and pray but I suspect that isn't the solution. If it's leaking outside it may be leaking inside too. Time to pull the head and magnaflux for cracks. Best to do it soon as water in a motor has some odd effects.

dave it cant be from the head there can it , theres an 1 1/2" gap to the water jacket where the chain runs
it must be from the water pump

i agree about the passage but i thought it was an oil one going up from the pump the water passage goes to the side below the line of the head from the diagram it would be where the 3/8" wall is that the covers the front of the chain passage so i would have thought it was a crack in the water pump housing

You could try this. It worked on mine, although it was probably a smaller head gasket leak than yours (mine was more of a seeping gasket). It works with antifreeze, doesnt plug up the system and drains out with the coolant when you drain the system. I was leery of the pellets and ceramic coatings due to overheating possibilities.

http://www.crracing.com/performance/chemicals2.html

Or, if you don't mind trying something 'old school' (actually, it's more like pre-school....), egg whites can be used to seal leaks in cooling systems. I've never done it and I don't know how well it works or even if there are any problems in doing it, but it seems pretty logical.

If you dump an egg white into the cooling system, preferably while it is nice and hot and flowing, it will cook. When it trys to get through the leak, it tends to get caught and stick. The more it cooks, the harder it gets til it becomes a chunk of carbon. The more than sticks, the better the seal. Plus, it seems to me, it can't be any worse in our cooling systems than some of the rust scale floating around in them.

Like I said, I've never tried it.

i think the "cook on the road side " method is best left to urban mith
it is the absolute last chance thing
you may get home but you will have to rebuild to clean the remains out of the engine ,rad and heater matrix (both of which will block )
better to use a modern chemical fix or replace gaskets
a small tub or your common rad sealer will fix a small seep and you can then drain the rad and fill with new water and antifreeze so you dont have a surplus in the system to block the rad and heater

ps if you have a rad full of rust flakes now is the time to flush the systemwhile antifreeze is cheap as the stores dont want to keep it on the shelf till the fall

if thats where your leak is coming from, between the head, block, and timing chain cover and your sure its not between the water pump and timing chain cover, i'd say that little "O-ring is leaking, or if a PO didnt know what he was doing when he put the motor back together it may not even be there at all.i had a motor where it wasnt even there at all, and go figure that was the motor that appeared to be freshly rebuilt, but with a broken number 4 rod that broke the block in pieces near the back, completely openeing up the oil journals in the bottom of the block, while jamming hte pistons at a 40 degree or so agngle inside the cylinder!!! best thing yet is it'd still roll over pretty nicely by hand or starter.