1999 volvo s70 where do I put antifreeze?

[alison]

I don't know where to put the antifreeze in my s70. Does it go where the coolant is? Do you have to drain the coolant? And does it need to be a 50/50 antifreeze-water mixture?

[E Showell]

Antifreeze and coolant are the same thing. In the summer, it elevates the boiling point in the cooling system above that of pure water and in the winter, it gives you freeze protection. Elementary chemistry teaches that any substance dissolved in water will both elevate the boiling point and depress the freezing point -- the nature of the substance and quantity added to the mix determines the magnitude of that effect -- (boiling point elevation/freezing point depression). That's why if you are hand cranking ice-cream, you mix rock salt in with the ice and water packed around the metal canister with the ice cream mix in it. The rock salt depresses the freezing point of the ice/water mix, but I digress.

"Antifreeze" goes exactly where the coolant does -- in the opaque white tank (the expansion tank) with the greenish blue cap just inside the passenger side fender and a little back from the front of the car. There is no need to drain anything to add "antifreeze." Also, best not to remove the expansion tank cap when the car is warm. If you are topping up the coolant, make sure you add a compatible coolant recommended for use in aluminum block engines. Several good premixed coolants exist so that you do not have to fuss with mixing coolant with distilled water. Best not to use tap water (too many minerals in it) and best not to use straight distilled water this time of year, especially in Colorado, where it can get pretty cold.

To give you a fully-responsive answer, most non-premixed coolants/antifreezes have a chart on the bottle indicating freeze protection characteristics for various mix ratios. Be guided by the chart, i.e., how cold does it get in your part of Colorado this time of year, and if you plan on keeping the car, only mix the coolant with distilled water. The minerals in tap water can do a number on an automotive cooling system.

[tryingbe]

Do not open the cap when the car is HOT. Only opens when it is cold.