1972 Fury Radiator Cap

[1970FuryConv]

When I got my 1972 Fury III, I was surprised to see that it has a coolant reservoir/overflow tank. Not sure when those came out, because my 1970 Fury did not come with one. I need to buy a new radiator cap. The radiator cap pictured hisses and loses pressure, such that the reservoir system is not operational, i.e. it doesn't draw coolant back into the radiator when the system cools. I wondered: is there a difference between radiator caps for cooling systems that have an overflow reservoir and those that don’t? How would I tell which is which? Thanks for your answers and recommendations.

 

[The Goose]

If it has a vent lever it's not for an overflow tank. The ones with the vent lever are one way flow. Your cap is correct type just a bad cap or wrong pressure setting for your application. My dad used to boil them to see if they worked. No need for that just go buy a good quality replacement. Happy hunting.

 

[ceebuddy]

The vent lever is just a safer way to release pressure in case the cap has to be removed while the radiator is still hot. You may use it with a reservoir, too.

Any cap (with or without lever) will feature two valves: A bigger pressure seal controlled by a sturdy spring and a smaller vacuum valve that may be kept close by a smaller spring, or hang loose and only close when hot coolant reaches the cap due to build-up of pressure.

The pressure spring will open when the designated pressure is exceeded and thereby release steam and coolant into whatever is a the the end of the overflow hose: the road or a reservoir.

When the engine is shut off the radiator cools down and coolant and air in the radiator contracts. Then the vacuum valve is either already open (if no spring) or will open because higher ambient air pressure forces media back into the radiator to equalize pressure. If there is no coolant reservoir then air is sucked into the radiator. If coolant had been lost through the overflow hose when the radiator was hot and this cycle repeats, the coolant level may drop over time and eventueally needs to be topped up. If there is a reservoir at the end of the hose then coolant will be pushed back into the (cool) radiator.

 

[1970FuryConv]

Great answer ceebuddy. I bookmarked this thread. You know your stuff!

 

[The Goose]

Wow. I stand corrected. My dads family had a Texaco gas station and shop in the 40's 50's & 60's. Closed sometime in the 70's I think. They did all kinds of voodoo , poured bearings, reverse charged old batteries back to life etc etc. That was one of his rules for our cars and I never thought to question it. That's too funny, sorry not trying to steer you wrong !!!!

 

[1970FuryConv]

Wow. I stand corrected. My dads family had a Texaco gas station and shop in the 40's 50's & 60's. Closed sometime in the 70's I think. They did all kinds of voodoo , poured bearings, reverse charged old batteries back to life etc etc. That was one of his rules for our cars and I never thought to question it. That's too funny, sorry not trying to steer you wrong !!!!

No problem Goose. I'm here to share, but I'm mostly here to learn. I think we both learned.

 

[The Goose]

No problem Goose. I'm here to share, but I'm mostly here to learn. I think we both learned.

10-4

 

[70bigblockdodge]

I think you would have to look a while to find one that does not work with a reservoir tank.

 

[1970FuryConv]

Carquest 10231 $5.39, 16 psi, installed. Should work with reservoir system because also spec’d for my 1990 W150, which has a reservoir system. Cannot test drive yet because I am making repairs to my taillight assembly and all associated wiring. Rear bumper off

car.