The Stovebolt Site Forums The Shop Area Engine Shop Cooling System questions for you.

My 59 Apache 1/2 ton with rebuilt stock 235 has a new radiator, water pump hoses etc for the restoration. Does the thermostat housing have a small,possibly threaded hole on the top or did the PO do something funky to this one. Would a stock radiator cap be best or a differnt pound rating? Thanks Ralph

Ralph,
I have a few OLD stock thermostat housings layin around the shop with a hole in the top for a pipe plug to bleed out excess air.
But they are pretty much all 1/8" pipe thread not a "small" hole.
Im no expert but everyone here seems to recomend a "stock" low poundage cap on the old engines.
Tim

If I'm thinking of the same threaded hole you are, it is tapped for 1/4" standard threads (stove bolt threads). I don't recall on the '59 models, but on older engines, there was a clamp on the fuel line that attached to that hole. The idea was to provide support for the fuel line. Frequently (sooner or later), the screw was left out after cooling system service or cylinder head work was done. If your fuel line has an unused, loose clamp somewhere on it, that is where it goes. As for the radiator pressure cap, I think the 15 PSI was standard by that time. A lower pressure cap would still work all right, as long as you are not driving at high altitude and with heavy loads on the truck.

Harvester

Correct pressure cap for the 59 is rated at 7 lbs. Had a 4 lb. cap on mine for years with no problem though.