Ok guys, I cant find a post on the forums so I am just going to ask. I am having to flush my cooling system and replace my radiation and t stat due to a transmission fluid leak inside the radiator. my question is how much antifreeze will I need to go back into my system? Also, instead of getting the cheap Autozone antifreeze can I get another brand/type that will cool better? The car is my 1986 Trans Am with a 350 bored .030 over and heat is kind of a problem running around town.

 

The rule of thumb is a 50/50 mix of antifreeze and distilled water. you can run 60% antifreeze and 40% water also. You can buy premixed gallons (I never do) or you can buy the gallons separetly. 1 gallon of antifreeze, then 1 gallon of water, then mix a 1/2 gallon of each and that should be enough to fill your system. You can use a coolign system additive. Royal purple ice comes to mind. results vary on how much it will help. Good luck

 

They used two bottles of purple ice on one of the hot rod TV shows and it worked about 15 degrees cooler. They had an old ford truck and did the pepsi challenge on it with before and after. The stuff did work but they had to use two bottles and they said it works best with straight water but does work good with antifreeze.

 

If heat is an issue, than run a 25% ratio of antifreeze and 75% water. Personally I run 50/50. But that's more so for convenience than anything else.

25% will give you freeze protection down to 10°F. If your location gets colder than that in the wintertime, bump the antifreeze ratio up some more. 25% should also give you enough corrosion protection.

60% will make your car run hotter than 50%, which will run hotter than 25%. While antifreeze does raise the boiling point of coolant, it also slows the heat transfer and thus makes your car run hotter. That's why a 25-40% antifreeze ratio works better than 50%.

 

1 gallon antifreeze. 1 bottle water wetter. rest distilled water. and i run green antifreeze in the 92 camaro as well as my 02 avalanche with the same mix. never had a problem. have ran this same mix in several vehicles in the past 15 years with no problems.