Antifreeze
 

I drained some very new antifreeze from my mustang and stored it in my garage for about 4 weeks. Can I pour this back into the car 4 weeks later or should I buy new again??

Has it been sealed or open? Be careful that nothing has gotten into it and contaminated it. I think if it were me I would just junk it. If it was sealed you can just pour it in. If you are just putting it into the reservoir you can just pour it in however if it is going directly into the rad make sure your car is running while you are pouring it in. Do not remove the rad cap when you car is hot though.

It's not sealed, it's been sitting in a drain pan on the garage floor covered with paper bags. I originally drained it to remove my intake manifold. The car should be running when I fill it up..huh??

The vehicle is a 1970 Mustang.

you can pour it back and run a freeze test on it with a cheap freeze tester...

you also need to make sure there were no pieces that fell into the antifreeze while it was sitting...

I am assuming you didn't completely drain the system or the rad? If you did you could fill the rad with the car not running and then start the engine and leaving the rad cap off while it runs pour the rest in

Okay perfect thx. I think I'm just gonna add some new stuff...I've come all this way..don't wanna screw things up now.

i'd rather spend 20 or 30 bucks on new stuff then spend the cash on a rebuild later, not saying you're going to bake the motor if you put the old stuff in, but for the peace of mind, new coolant would be the way to go IMO

Good decision, good luck also just be carefull you do not get burned putting it in and remeber to mix the new stuff 50/50 with water.

Yes I totally agree. I actually put the old anitfreeze in containers just last night to get ready to dispose of them. I'll make sure I wear goggles when the car is running as I pour.. Thank you very much. I'll post pics later tonight of what I've done so far..but she's just about ready to fire up. :)

if it isn't already pre-mixed, try to use distilled water if possible