Took my grandson's 73 Dart to the inspection station a couple of days ago, and noticed a slight overflow of the radiator when I shut the engine off. Got the car home, vented the Stant radiator cap, and KaBlooie....

Last two projects did the same thing, so I pretty much knew what to do. Took the radiator out and took it to the shop. Flushed engine and heater. Replaced all hoses too. One area which I think had a lot to do with the problem was one I hadn't dealt with in a long time and serves as a good reminder...the small hose running from just below the thermostat housing to the top of the water pump was cut to the wrong length by someone. Consequently, it was twisted and all but blocked off the water flow. Good thing to check on these engines. Simple fix, get another length of 3/4" hose, cut to proper length and reinstall. Just thought I would pass that along.

That bypass hose is 5/8".

Also another commonly overlooked area in cooling is the block itself. Pop some of the freeze caps off or the block drain plug (on passenger side near oil filter, its a square plug, not sure if all engines had these) and if water doesn't come out, then you have a problem I remember reading some posts on these boards or others that when people removed the plug it was clogged completely shut.

Craig: Nope...3/4" in this case. Someone changed the nipples. Thanks though. Looked into some technical stuff I had on hand and the 5/8 would have been correct if all original.