The Stovebolt Site Forums The Shop Area General Truck Talk radiator coolant recovery

I installed a mason jar as a coolant recovery container. The radiator will flow coolant into the bottle but will not recover it. I am using a 7 pound pressure cap. The mason jar has a 2 quart capacity with a vent to the atmosphere. No doubt I have done something wrong and need some advice. I used AN fittings into the original mason jar cap. The tube that connects to the radiator goes all the way to the bottom of the jar. Does the system have to be air tight to work?


Weeds

maybe what it's pushing out is the amount you've overfilled it .... a 283[?] with a stock-ish rad and a 7# cap won't/shouldn't get hot enough to need a recovery system, just don't fill the rad to the top and it'll quit pushing anything out

Bill

I would think it would have to be sealed to draw the water back in or it just draws air from the out side.

I think that Ron is correct. The GM accessory unit either has parts/instructions to convert the radiator cap, or it provides an appropriate cap. See figure 12.

Up to 1954, track radiator caps were often 0 psi pressure (except for big trucks, in some models/years). So, there would be no need for a modification in a truck/radiator that has a zero pressure cap.

The recovery tank cannot be air tight. If it was then when the vehicle is running the recovery tank would be pressurized just like the radiator and that's a bad thing, especially since you are using a glass container!

It sounds like it is set up correctly. The tube that goes to the radiator goes thru the recovery tank lid down to the bottom of the recovery tank. The other opening in the cap serves as a vent. The radiator pukes fluid into the recovery tank and then when the engine is off and the radiator starts to cool down the vacuum that results from the cooling will suck the fluid, via the submerged tube, back out of the recovery tank.

It's no different than drinking Coca-Cola from a straw. As long as the straw is submerged in the Coca-Cola you can suck the Coca-Cola out of the bottle. If you somehow had the straw in the bottle and the pop bottle was sealed you couldn't suck the Coca-Cola out 'cause you would be inducing a vacuum into the bottle.

I am really confused now. Hot Rod John says vent, WEbOLD says don't vent. Any other opinions?


Weeds

I think the confusion is due to defining what you want the tank to do.

Check this out: http://www.custompistols.com/cars/articles/overflow.htm

The use of an overflow tank (vented non-pressurized) is done for environmental reasons. It prevents a slightly overfilled radiator system from venting onto the ground.

The use of an expansion tank (pressurized), with a conventional radiator, adds a very small amount of additional coolant to the system.

Hope that helps!

John

if the system was sealed the recovery container would have the same positive and negative pressures as the rad and engine [which use a 14# cap or higher], I doubt the usual plastic reservoirs would stand that, let alone a mason jar [as John explains]

I'm pretty sure Weeds is running a 283, and states he has a 7# cap, a 283 with a 7# cap shouldn't normally run much over the thermostat rating, so will not generate the temps and pressures necessary to make a modern style recovery system function, it needs the more extreme contraction to draw the water back from the tank

283's blowing off a bit has been the subject of threads here before, and it's invariably a situation of filling the rad to the top when cold instead of leaving enough head space for expansion .... I'm sure if the bottle were emptied without topping off the rad, it wouldn't "flow coolant into the bottle" again

Bill

John, thanks for the link explaining the differences between the 2 systems. I thought they were one and the same. Bill, I am running a 283 and your explanation gets rid of the confusion on my part. The quantity of coolant in the mason jar has stabilized at about half full so I won't add any more coolant to the radiator. My education continues and this Stovebolt site is like old truck college.


Weeds

after reading the other responses i was wrong. the coke analogy works.

The 47-55 overflow tank (Radiator Overflow Condenser) is not air tight. It has an inflow pipe from the radiator and another pipe/hose to equalize pressure.

I also forgot that Weeds is not referring to an original overflow set-up.