My truck has been sitting a little while and I need to get it down to my mechanic for some other issues. I need to get a coolant drain and replace cause its been a couple years and I was wondering if it would be safe to just add water to the reservoir to get it to the mechanic? It is pretty low right now.

 

There is no reason to not to run water in the system. The value of the antifreeze is to keep it from freezing in the winter. Some people run water only, distilled ideally, if you live somewhere that never freezes.

 

Sure.

Coolant is just fancy water. It's stuff that takes the heat away.

As long as you arnt going 200 miles in +100f. Or letting it sit in freezing conditions, it will be fine.

I used to run vehicles on just water all the time. Until winter, then added antifreeze.

You say you're swapping it anyway, tell the mechanic so he knows.

All good.

Caveat. As long as the fluid level isn't low because it's leaking out fast from some place.

 

As stated water is cool. Cooler than antifreeze

 

Though it's worth noting that antifreeze also helps raise the boiling point of water. Since most engines operate (for emissions purposes) very near the "red zone", something needs to help keep the solution from boiling.

So, while pure water is the most efficient fluid for heat transfer, it's always recommended that at least some percentage of your coolant consists of antifreeze. I always err on the side of more water though.


(It's also why a functioning overflow cap is important - pressure also suppresses boiling.)

 

Down side of water is a calcium build up plugging your radiator. Distilled water with coolant is the only way to go.

 

Yes! Always distilled, except in absolute emergencies.

 

Thats why it is refrered to as COOLANT these days and not antifreeze any more.