Change Coolant

[Michael_]

Hi,

I want to completely drain and refill the coolant in my 69 charger rt with the 440 engine since i dont know whats in there and when it has last been changed.

I just read the shop manual.
They suggest to change it once a year and say there are drain plugs in the engine block and radiator.

I did a little research and read something like "good luck if those plugs in the block have never been opened bevor".

So bevor i do anything.
How good are my chances to get it open and is there a special tool that will make it easier or i need because otherwise i have no chance?

 

[451Mopar]

The small (1/8" NPT) plugs in the block are near the motor mounts. I think the original plush had a square head, if replaced may have a hex head?
Sometimes they will be rusted in place pretty good. On an older engine there can be a lot of buildup inside the block, that after removing the plug, nothing will come out, so might need to pole through the scale with a round punch or phillips screwdriver for the coolant to drain from the block.

 

[69Bee]

The block side plugs should be 9/16", so use a 6 point socket for better grip, as a 12 point socket can lead to rounding off the plug. An impact will make the job easier, BUT if you have problems, just knock a freeze plug sideways and pull out to drain each side. As far as the coolant, use ethylene glycol (green) coolant and mix 50/50.

 

[Michael_]

Thanks.
Okay i will use a long wrench and hopefully i can get that bolt loose without to much trouble.

 

[tonysrt]

May be apply some good penetrating oil before you tackle those plugs. If you do get them out you can replace them with petcocks so they'll be easier to drain in the future. If you decide to take out a freeze out plug make sure that it is accessible to install a new one.

 

[tonysrt]

My 58 Fury 350 blew out a freeze out plug and it was so unaccessible that I had to use a rubber plug to stop the leak. They do work especially when there is no room to pound it in.