Rant: Heard a guy at the parts counter telling a customer to just top off their coolant with water, no matter what

I was picking up a thermostat gasket yesterday and the guy next to me was asking about a coolant leak. The counter guy said, 'Just keep adding water, it's all the same stuff anyway.' That's flat wrong, especially with modern aluminum blocks and the different coolant types. Using straight water can cause corrosion and won't protect against freezing or boiling like the proper mix. Has anyone else had to correct this kind of bad advice for a customer after the fact?

3 comments

3 Comments

stella3072mo ago

Flat wrong" seems a bit strong. For a small top off in a pinch, a little water isn't going to ruin the whole engine. People have been doing it forever without disaster.

cameronrivera2mo ago

Yeah, but it's about the coolant mix. Straight water doesn't protect from freezing or boiling over like it should. I had an old truck overheat in summer traffic because the mix was too weak. Had to get the whole system flushed after that.

emery9651mo ago

For a simple top off it's fine, but people get lazy and keep adding water instead of fixing the real problem. A 50/50 mix is cheap insurance compared to replacing a blown head gasket from running straight water in the summer. A little water in the system here and there eventually turns into a mostly water system if you never drain and refill.