Coolant Flush?

[TrevDaddy]

I searched with few results. It just hit 19 degrees in STL, and I have no idea if my coolant can take the abuse. When I looked under my rad cap, it seems like the liquid is clearer than it should be. I know that a couple of gallons of Prestone will be needed, and maybe a new thermostat. The rad hoses are fine, look new.

 

What is the procedure for this? Will my service manual detail what is need to be done? I know that disconnecting the lower rad hose will get most of the fluid out, but is there a block drain plug that will drain the rest? Is a push through method needed (water hose)? This is important, I really want this thing to survive the winter.

 

Trev

[datzenmike]

I think a gallon would be plenty. Too much anti freeze will raise the freezing point. There is a plug on the right side of the block to drain the lower water jacket around the cylinders.

[chavezYchavez]

Pard,

I just did this to my 73 620 dont think it had ever been done before as it was really dirty. Go to autozone or Walmart and buy prestone Radiator flush comes in a med size yellow container http://www.prestone.com/products/coolingSystemTreatments.php it takes about an hour to complete the process. Then refill with a 50/50 antifreeze and good to go mine is good to -30 below and boilover of +290 after doing this. In the spring I plan on removing the radiator completely and having it hot tanked at a radiator shop. A 36 year old radiator needs to be deep cleaned after so long I was just worried so did this quick flush to make sure it would go thru the winter. Hope this helps and good luck.

CYC