Seasonal question: Water for anti-freeze for winter or summer?

I went to two different mechanics and one told me that you can run your car in the summer with just water, HOWEVER you can’t get away with that during the winter which apparently is when you need the anti-freeze the most. Then another mechanic told me the polar opposite that it’s the winter when you can use water instead of anti-freeze and you’ll be ok whereas summer you need anti-freeze more. Please don’t just tell me that you need anti-freeze for both seasons because I know it will cause damage to parts of the car if you don’t. I’d like to know which season can you get away with just water because it’s bothered me how I got conflicting words.

Thank you

You need to use antifreeze all year round.

It protects from overheating in the summer and freezing in the winter.

It protects the cooling system from corrosion.

And it lubricates the water pump.


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Thank you. But like I said I understand it can cause damage but I wanted to know what I could get away with in which season.

NEVER USE JUST WATER. It’s that important. 50/50 all year is pretty standard. Anyone that says you can use just water is wrong.

Both those mechanics are nuts.

Neither seasons, but not just because of corrosion damage to the engine. Coolant provides both freeze protection in winter and boil-over protection in summer. It not only lowers the freezing point, but raises the boiling point. Straight water in summer will boil and steam out of the radiator cap when it over-pressurizes the cooling system. Then, you have less water in the engine and it’ll overheat.

You can’t “get away with it” long term any season. Short term, of course, cooling the motor is more acutely important. In reality, why would you ever replace a recommended ratio of 50 to 50 percent coolant, specific for your car for example with pure water. It’s usually a matter of topping it off with water in an emergency then changing over before winter. So theoretically, you always have "some of each " which is perfectly adequate temporarily. It your intent is to use water for the sake of using water or evaluate what a mechanic says, it’s not worth your time and why mess around with the theoretically, second biggest investment in your life. Use what the manual says…a mixture using the right coolant which often is specifically recommended for your car. I know you don’t want the discussion to go in the way of proper coolant mixture, but in reality, nothing else matters as being suitable long term for your car.

Mannn…the mechanics I went to were f*cking idiots…

Water freezes and expands at 32 degrees. The expansion will crack, radiators, engine blocks and heater cores. Antifreeze raises the boiling point. This keeps the car from overheating and blowing a head gasket. As said it keeps the internal parts from corroding.

I am having a very hard time taking the OP’s question seriously, but I will overcome my skepticism to explain that “anti-freeze” functions as both a very effective coolant in warmer months and to prevent the engine’s cooling system from freezing in the winter, and that additionally it contains anti-corrosion agents to protect the cooling system, the heater core, and the engine from rust.

Using only water will lead to the following:

Accelerated rust & corrosion of the cooling system and the heater core and–possibly–the water passages in the engine.
Early failure of the water pump
Overheating in the summer
“Freeze-up” of the cooling system and engine in the winter

Why am I skeptical?
Because I have a very hard time believing that a mechanic told the OP that “you can use water instead of anti-freeze” during the winter. Even the untrained kids at Jiffy Lube would know that this statement is so wrong as to be…incredible.

Ya got that right!

Edit: In response to Jim Frosts latest post.

If your name is really “Jim Frost”, they were probably pulling your leg so to speak. In the Continental USA almost anyone over the age of 10 now knows it is “engine coolant”, rather than antifreeze. Your owner’s manual will make all this very clear.

A name like “Jack” might illicit a similar response.

I almost suspect that this person is just messing around. If not than he needs to find someone who can really help them instead of these so called mechanics. I say this because of their other posts.

When I was 8 years old, I knew that antifreeze was essential in the winter–if you didn’t want to wind up with engine damage. And, when “permanent antifreeze” became the norm many years later, everyone whom I knew–including women who are totally non-mechanical–knew that you are supposed to use it all year-round.

I am VERY skeptical…

Doc, I still often call it antifreeze… and I’m over 10. Heck, my SHORTS are over 10!
Perhaps it’s a regional thing.

@the same mountainbike–No matter what somebody calls it, I am extremely skeptical about a mechanic ever having told the OP that he can use plain water during the winter. Even during the summer, it is absolutely a bad idea, but…during the winter?

I think that this person is trying to yank everyone’s chain.

Yeah, I absolutely agree with all the points made. Just going for a chuckle.
I do, however, believe the OP when he/she says a mechanic told him this. I’ve heard stranger things.

“I do, however, believe the OP when he/she says a mechanic told him this. I’ve heard stranger things.”

While I remain highly skeptical about the original question, if a so-called mechanic actually did utter that nonsense, then he needs to put down the wrench–or put down the bottle that he is guzzling from.
No competent (or sober) mechanic could actually say something this outrageously incorrect.

I agree that if the statement is accurate, and the guy who made it claims to be a mechanic, this is one guy that should be put out to pasture… however, remember that the oil drainers at Jiffy Lube are perceived by many a customer to be a “mechanic”. The comment could have come from anywhere.

technically what it protects from in the summer is boiling over, not overheating.
although loss of coolant could lead to overheating.
it protects from freezing in the winter, and corrosion always.

In olden times, they used water in the summer and an alcohol water mix in the winter.
But cars ran much cooler then. And probably had a lot more problems than rusty water.