Demineralized vs distilled water in radiator - problems?
Posted: Mon Jul 18, 2016 3:55 pm
Hi,
as I am still gathering $$$ for engine repair (coolant leaking on head gasket + chains replacement = 2k EUR) it became a habit to have sometimes more water with me than gas
During winter I had to add approx. 1 qt every 200-300 miles as dripping was more like a personal waterfall.
Then I found very cheap DEMINERALIZED water (60 cents for 5 qt) in our local supermarket, and I begun using this one instead of more expensive DISTILLED water. (NOTE: Demineralized water is produced by adding chemicals, which make minerals and hard particles to collect on the bottom, so there are some leftovers of those chemicals for sure. While distilled water is pure vapor distillation, no chemicals added)
Then came the Spring and Summer.
Now, here comes the weird part: Coolant is not leaking anymore.
I am asking myself, whether that's the consequence of:
- either Summer temperatures
- or rust and residues, produced by chemicals of demineralized water (...as I noticed radiator inside at filling cap is covered with thin layer of brown something....looks like rust. And I can tell for sure it was NOT there before)
So I just wanted to do a CLEANING of cooling system with Coolant Flush & Clean...but now I am not sure anymore whether it is a good idea. I might remove garbage which sealed the leaking gasket, rendering leak even worse than before.
What do you say?
as I am still gathering $$$ for engine repair (coolant leaking on head gasket + chains replacement = 2k EUR) it became a habit to have sometimes more water with me than gas

Then I found very cheap DEMINERALIZED water (60 cents for 5 qt) in our local supermarket, and I begun using this one instead of more expensive DISTILLED water. (NOTE: Demineralized water is produced by adding chemicals, which make minerals and hard particles to collect on the bottom, so there are some leftovers of those chemicals for sure. While distilled water is pure vapor distillation, no chemicals added)
Then came the Spring and Summer.
Now, here comes the weird part: Coolant is not leaking anymore.

I am asking myself, whether that's the consequence of:
- either Summer temperatures
- or rust and residues, produced by chemicals of demineralized water (...as I noticed radiator inside at filling cap is covered with thin layer of brown something....looks like rust. And I can tell for sure it was NOT there before)
So I just wanted to do a CLEANING of cooling system with Coolant Flush & Clean...but now I am not sure anymore whether it is a good idea. I might remove garbage which sealed the leaking gasket, rendering leak even worse than before.
What do you say?