What's this fitting on the radiator?

TAZZ

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1974 charger 318. Ours didn't have one when we got it several months ago. Just a plug. Some kind of a choke control, heat for the carb? See red arrow at radiator. I also noticed the red cable as a ground.??

Arrow at fitting on radiator.jpg
 

pnora

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There is a sensor for emissions that screws into the radiator. The red cable was replaced at some time for the original black.
 

tonysrt

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My 75 Plymouth 318 had that fitting in the radiator also. The car is long gone though after 150,000 miles.
 

Charles Cook

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Take that cable off and replace with a black one or spray paint it black. You may not hook something up backwards but someone else may. Ask me how I know. Lol
 

TAZZ

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Take that cable off and replace with a black one or spray paint it black. You may not hook something up backwards but someone else may. Ask me how I know. Lol
Not my car. Just a picture I found on the net. I was surprised to see that in such a neat engine bay.
 

RJRENTON

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1974 charger 318. Ours didn't have one when we got it several months ago. Just a plug. Some kind of a choke control, heat for the carb? See red arrow at radiator. I also noticed the red cable as a ground.??

View attachment 1249350

Yes....its an emission control device....called a thermal vacuum valve or switch. The purpose was to control the ported vacuum signal to the EGR (Exhaust Gas Recirculation) valve. Below a certain temperature, the EGR signal was disabled until the coolant reached operating temperature, the valve opened and subsequently the EGR system functioned. EGR was introduced in the fuel charge to lower combustion chamber temperature to prevent/reduce NOx emissions.
BOB RENTON
 
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