Radiator Cap Question

[30Tudor]

Can somebody please explain to me how my quail radiator cap is supposed to work from a sealing perspective. The reason I am asking is that I think I am occasionally getting some fluid discharge out the top of the cap where the quail attaches to the cap. Also occasionally I get some fluid on the top of the radiator or spraying into my windshield. This is not a chronic issue, just occasionally. I have a fluid recovery bottle mounted above the engine which is attached to the overflow pipe. I also have a 160 degree thermostat.. I am confident the seal is good from the radiator to the cap but there is an inner plug in the center of the cap that I am not sure that is sealing. THanks for your help.

[1931 flamingo]

Skip should chime in here pretty quick, but there is a kit available from vendors with 2 gskts and attaching hardware for a quail cap. Basically remove the quail, then the adapter, repl gasket where rad cap would go and then the gskt under the quail where it closes. Solved my same problem.
Paul in CT

[skip]

Hear here. The man is right.

Quails, with or without a thermometer have a tendency to defaecate upon the windscreen in regular fashion.

Some common sense needs to be injected here. The cooling system is a 3 gallon affair. No more than 2-1/2 gallons is needed to circulate around to cool the engine if the radiator is free flowing and grease free and has tight fins to tube contact. Were talking a 1930 unit. Were talking mine. I did make a water dip stick for peace of mind. Hot or cold I know where my level is. I don't use a restricting thermostat and I don't overheat if the timing is right. That's a whole nother ball of wax.

Any more water than 2-1/2 gallons in this non pressurized system tends to puke out the overflow tube or out the top of the radiator. And an overflow bottle does little good and has generally been not needed for 80 plus years, millions of 'A's and billions of miles. But I could be wrong.

Let the radiator find it's own liquid level as the water temp usually hovers around 160 deg F. and that is 52 deg F less and far below the 212 deg F that straight water boils at. And even a higher boiling temperature can be had if running a 50/50 mix of antifreeze, water pump lube and Wetter Water. So ask yourself...'How hot is hot?'

The adapter that the Quail sits on must have 'spot-on' gasket[s] and if two gaskets are needed lay in some non hardening Permatex #2 goop 'tween them if using two gaskets.

You see the first problem is a radiator that has both neck tangs that is a little splayed out by being over tightened by the previous owner. Usually to stop the Quail from leaking.

This over tightening and thus lifting [bending up] of the mounting tangs in the neck of the radiator is caused by the two Allen key screws that pull a bar up.
That bar is mounted under these tangs and if the tangs are already pulled up that creates the need for a second gasket. I would not recommend trying to 'beat' the old hard cooper tangs back into their original position.

OK. Two gaskets under the mounting for the Quail creates a seal 'tween the radiator and the mounting. This must be sealed and water tight. Even though we don't run pressure it can and does pee out a little water if the liquid level is too high.

Now the Quail. She must sit on a perfect sealing gasket[s]. Same story as above.

And the last gasket, the one that the Quail closes on and twists 90 degrees to lock must be a complete seal.

This gasket under my Quail was too large in the outside diameter. Inside diameter was good. I could trim the outside edge but I'm too old for that kind of surgery with a razor blade. I considered an 'O' ring from a NAPA store; NAPA has a variety of sizes and could even make one up if needed. But I decided to cut her.


So I cut a tiny bit out to shorten the 'circle' and than refitted it back together inside the groove, using my dental explorer instrument to push it down for a good fit with Permatex #2 to hold it in place.


A dab of Vaseline under the Quail's disc lets her slide down, twist and lock on without distributing this resized and Permatex'ed down gasket. This was a two day carefully orchestrated affair to get it right after months of fretting about it and cutting my own gaskets. I finially ordered a double set of all gaskets just in case I needed doubles, which I did.


And a nice long drive to heat things up and set all the gaskets and now my Quail fails to defaecate on my paint, bonnet or windscreen.

skip.

[30Tudor]

Thanks Skip. I really appreciate the reply and had a good laugh about your term "Quail defacation" which is now going to be part of my Model A language. I'm pretty sure my gaskets are tight, however, I will look at them again. Do you think I could have some leaking in the center of the cap? There is a connection point there with a 1/2" hole on which the flange is rolled over onto the main sealing flange (can't send a picture right now). Should I just seal this off with gasket sealer as well?

[skip]

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"Do you think I could have some leaking in the center of the cap? There is a connection point there with a 1/2" hole on which the flange is rolled over onto the main sealing flange (can't send a picture right now). Should I just seal this off with gasket sealer as well? "

No I don't think so. When I first started to fool around with this problem I tried a sold one piece neoprene gasket covering that entire disc with the 1/2 hole in it. No good. Still leaked out but never from this hole.

That hole in the center of the rotating portion of the cap is a blind hole and is there to provide some leeway for the flat disc to seat properly under the Quail. If that disc did not move, than it would be really hard for that disc to seat and seal onto the gasket [the gasket I shortened and Permatex'ed down] because of the tilt needed to close the Quail.

I suspect the gaskets and/or the fit of the gaskets.
A water molecule is pretty small and can find it's way out from under very easily.

A drop of food color at various gasket levels from bottom up can help trace the water's movement. Start at the bottom and work up. Your not going to find it in day.

skip.