Coolant recovery

[7duster4]

I have a 1974 Duster. I believe this was the first year they came equipped with the coolant recovery system. I also still have the factory 26" a/c radiator. No problems over-heating but a question regarding the yellow container to the left of the radiator. I always thought the purpose was to add coolant and if the radiator was low it would suck that extra coolant in. I have a small leak so from time to time I have been adding some to the container and once I was low that extra fluid would find it's way into the engine. I took the car out today but didn't add any, the container was almost empty. When I got back I looked in it and it was almost full of boiling coolant. A couple hours later I checked it again and it must have all gone back in because it was almost empty. Is it normal for fluid to be pushed out of the radiator when hot?? I was surprised to see that. Before I drove I also popped the radiator cap off and it was about full so I didn't feel the need to add some to the yellow container. Is this supposed to happen or is something wrong?

Thanks for any info.

 

[64physhy]

As the coolant in the radiator and engine heats up, it expands, so needs someplace to go, so it goes into the overflow bottle. As it cools, it shrinks back to its original volume. Since the tube going into the overflow tank goes to the bottom of the tank, it siphons the fluid back into the radiator. Your overflow sounds like it's working correctly, but having boiling water in it is not normal. Several things could cause the boiling coolant: not enough anti-freeze (it also acts as an anti-boil), bad radiator cap, leak in the radiator or one of the hoses, bad thermostat (or no thermostat), bad water pump. I would start with the cap, especially if it hasn't been replaced in a long time.

 

[7duster4]

As the coolant in the radiator and engine heats up, it expands, so needs someplace to go, so it goes into the overflow bottle. As it cools, it shrinks back to its original volume. Since the tube going into the overflow tank goes to the bottom of the tank, it siphons the fluid back into the radiator. Your overflow sounds like it's working correctly, but having boiling water in it is not normal. Several things could cause the boiling coolant: not enough anti-freeze (it also acts as an anti-boil), bad radiator cap, leak in the radiator or one of the hoses, bad thermostat (or no thermostat), bad water pump. I would start with the cap, especially if it hasn't been replaced in a long time.

The coolant didn't rise when I looked in. But it was steamey. This was less than five minutes after shutting the car off. Makes sense though as far as being siphoned back into the radiator. The cap is a couple years old, it's a stant but can't remember the lbs rating.

Thanks

 

[yellowdartdave]

The coolant recovery system was first introduced in the 1973 A-Body as part of the Max Cooling or Trailer Tow Package or the A/C package.

When you shut the engine off, there is no more cooling going on. The engine is still hot and it will actually boil the water out of the radiator. In the 'old' cars, it would end up on the ground.
With the recovery system, it puts the water into the bottle and when the water cools down, there is a slight vacuum in the engine which thermo siphons the water back into the radiator.

Just as you shut your engine off, check the guage, wait about 5 minutes and check it again....it will probably be up near the top of the heat range.

http://www.hamtramck-historical.com...hipDataBook/1973/73_Dodge_Engineering0025.jpg

 

[myraley]

Say, could either of you post a photo of the coolent recovery system you are talking about? I want to add a stock type overfow tank to my 67 Dart, instead of that dumb square box I have from Autozone now, and want to verify how it goes in. It should work, right?

 

[superdart]

Check the pics here, it will show you how it goes. I'm not sure it will work thought because I *think* the older radiators are different.

The stock bottle was leaking on my '75 (and it looked like crap) so I put on an aluminum recovery bottle and it looks/works great: