2 style radiator caps- where to buy what I need
Only out drip tube and not while running or under pressure. Only when engine is shut off and heat soaks. Pressure goes up and it dribbles till it cools down a bit
You are fine.
You could remove a few cups of coolant to lower the level to about 1 inch below the filler inlet.
Basically with a non recovery system. After all the air is expelled from the system (a few heat cool cycles) as the fluid expands as it gets hot it will raise the pressure of the coolant to 13 lbs, any pressure over that will be released by the rad cap. Assuming the coolant is filled to the top some coolant will also come out.
When it cools and the coolant contracts, air will come back in. After a few cycles like this (assuming you never get the engine any hotter than the last time coolant dribbled out) you should not have anymore coolant dribbling out.
The system is actually designed to NOT be filled to the top. There should be an air gap (about an inch) below the bottom of the filler neck.
In a recovery system...
The coolant is filled to the top of the radiator, full. The hose goes to the bottom of a recovery bottle, there is another hose from the top of the bottle to atmosphere.
The bottle gets about 1/2 full with coolant.
As the coolant gets hot in the radiator it expands, creates pressure in the cooling system and since the rad is 100%full the excess coolant goes into the recovery bottle. ( You can see this happen when the level in the bottle goes from "cold" to "hot" marks on the side of the recovery bottle.)
When the engine cools the coolant contracts and pulles fluid back in from the recovery bottle.
If you have a hole in or a loose fitting tube from the rad to the recovery bottle the fluid will not get pulled (yes I know atmosphere actually pushes the fluid) back into the rad.
Hope that helps.
By the way, I do recall now, WAY back in the day rad caps did not have the larger washer just under the cap, that was added for recovery systems BUT will not effect the function of the non recovery system.
As to 2 types of caps, these days there are vented caps the type with the lever, to make removing a hot rad safer, ( just let it cool) and the standard cap that justs twits on and off. BUT both caps work the same way and will work fine on either type of system.
One last thing if you always loose some coolant out the tube, than you might have other issues like head gasket leak or crack in the block, adding combustion pressure to the system and forcing fluid out. ( Like blowing water out of a straw)
