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How to purge coolant system on Eldorado 1973

2061 Views 9 Replies 3 Participants Last post by  Ranger
Hello everybody,

I want to know how to flush the coolant on my cadillac eldorado convertible 1973?

Indeed, I've noticed that when I drive for a certain time and that the motor has time to warm up, when I stop the engine I hear a boiling noise from the upper hose (the one that starts from the thermostat to go to the top right of the radiator and which spans the air conditioning compressor).

I touched the hose is not under pressure and hard, I think it's a good point. I precise that the water pump and thermostat are new, and joints.

So that is why I was thinking of a purge of refoidissement system as I have done wrong, so I wanted to know the procedure to drain properly.
No overheating symbol lights up on the dashboard.

I also noticed that I my heater does not work (the fan works but no hot air) ... Is there a link between this two facts ?

I await your response eagerly!

ps: I'm French so please no abbreviation or I do not understand: D


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No heat and bubbling mean that there is air in the system. Is the system full to the correct level?
Thank you for your response,

What level are you talking about?
Coolant level. Is the radiator full to the cap opening with? If there is a reservoir is it filled to the full line?
No the radiator is not full, and the reservoir is almost empty. But I suddenly have a revelation thanks to your response, maybe I have not quite filled the radiator. On one site I found that there should be 9.46 liters of coolant, and there on another I discover that it takes 20 liter !
It's change everything !

So what is the maximum capacity of the engine coolant? (In liter?)
Not sure, but it doesn't really matter. Just fill the radiator until it's totally full, and fill the reservoir to the fill line.
it seems obvious to me now, I thought it was weird to put 9 liters of coolant and see that my radiator was not full, but I did not think he was filling it to its maximum capacity

I'll refill tomorrow and my problem should be solved.

Is there a chance that my heating starts to work? I do not understand why the fact that there was air in my circuit makes the heater does not work? Yet I hit the water pipes are all hot
Hot coolant flows through the heater core, and air blows past the fins and gets warmed. If there's air in the system, there's little to nothing flowing through the core at times, so nothing to warm the air.
Ok thank you for this precisions, it's very helpfull !
Once you fill it (and add a pint or so to the reservoir), be sure to check it again after you drive it once or twice. There should always be some coolant in the reservoir and the radiator should always be filled to the cap.
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