65 289 with a stock cooling system. No air conditioning. The radiator, water pump and thermostat were replaced about 2 years ago and don't even have 500 miles on them. Recently started driving the car after 22 months of working on it.
It was fine for a while. Now, after I park it I am losing coolant, apparently through the overflow tube. The engine temp gauge seems to work and the car is not running hot, nor does it smell hot.
Any ideas?

 

Install a catch can if it is bothering you. Without it everytime you top off the radiator it will overflow to 'find its level' which is just fine as long as you are not running hot.

 

The coolant should be an inch below the filler neck when cold. If you fill it any higher than that, it'll overflow every time.

 

I installed a over flow on my '65 289. Where does your Mustang run at temperature wish?

 

plus one

 

yea head to the pick a part! or use an old fire extinguisher.

 

After it finds it's level a new 14 psi radiator cap couldn't hurt.

 

The older you get the more coolant you loose. Just ask the young chicks.

 

Yeah get a overflow tank or ignore it.

 

Not an overflow can, but a recovery or expansion tank. An overflow or catch can will keep coolant from spilling onto the ground, but it is a top feed and simply stores it. You need a recovery tank that fills from the bottom and is vented on the top. As coolant heats up and pressurizes it expands. When it reaches the psi of the cap, it pushes up against the plunger which allows it to pass the seal and vent out the cap hose. By running this to the recovery tank, it will expand into the tank and then return as it cools. Once fully purged, you maintain the coolant level through the tank, not the radiator. Here are some examples from Summit:

http://summitracing.com/search/?keyw...recovery&dds=1