Radiator Question

[farrellg]

What is the correct water coolant level in a non pressure radiator? I have been working on these for years, how ever, it seems they all find their own level. Reason I ask, on my 1931 4 cylinder U124 truck, I believe the level it settles to is lower than I like. I can still see it when opening the cap, but is only about 1/2 full on the top tank.

[JACK M]

I wouldnt worry unless it runs hot.

[keiser31]

My '31 DB coupe runs with the water about 1 1/2" below the filler.

[Guest 1930]

Like you said they find their own comfortable spot by way of the overflow tube. I wouldn't worry about it either unless it runs hot

[Guest DodgeKCL]

Like Jason says if you overfill the rad it just runs it out the overflow tube until it finds it's own level. I know I've got too much in it when I turn a particular corner on my paved driveway on the way to the garage and I leave a trail of antifreeze. This always happens when I re/re the antifreeze every 3 or 4 years. It eventually settles down on it's own.

[farrellg]

Thanks for the replies. I really never worried about it as long as it did not over heat. I have several older pieces of farm machinery, non pressure systems, and always just let them be. Thanks

[Pete K.]

Some folks used to set a roofing nail in the overflow tube to keep a higher level of coolant in the top tank. I hope they had a good cap gasket! Just a slight amount of "build-up" of crud on the inside of the radiator tubes will be enough to keep the coolant from flowing fast enough through the core, therefore coolant will flow out the overflow tube since it has nowhere else to go. As the core becomes progressively blocked, the upper coolant level will drop until one experiences overheating. Usually, the water pump will keep doing it's thing with gusto, filling the top tank from the engine. Just a side note; 1930's Pontiac's used a "cross-flow" honeycomb radiator core like many of our modern cars use today. I never drove one so I don't really know if that helped with over-feeding the top tank of a radiator that has a build up in the tubes.

[farrellg]

I do know when you look at various radiators, the overflow tube height and relation to the cap varies some, most likely from years of funnels being placed in the fill hole.

[Pete K.]

There's been much discussion of the overflow pipe location on various forums and the consensus is the pipe should be low enough to not contact the radiator cap, of course, and towards the BACK of the neck, as we face the car. Works well for Model A's! My '25 Dodge's pipe is soldered in sort of towards the right of the neck as you face the front of radiator. Height seems to work OK. It seems that someone had pinched the tube opening into a tight "oval" shape, maybe to restrict coolant overflow. I'm leaving it like that. It seems to work too. WORD TO THE WISE--Be careful bending those old tubes in the neck. They are BRITTLE and will crack farthur down the tube where you don't want a HOLE! Don't ask me how I know this.