rust in water

[robgross1930]

Originally Posted by daveymc29

I have always had pretty good luck with the water being clear of rust in my cars. I use a bit of soluble oil in them with distilled water as my choice of coolants here in sunny CA at sea level + 384 feet. Then recently I had occasion to examine the radiator water on the roadster and found it low so I added a bit and went for a drive. When I got up to freeway speed, around 55, I noticed an orange froth just below my moto-meter. Got home and checked, never saw it rusty like that. What could have made the engine rust up that fast? I drained it all and filled with vinegar and will drive it a few weeks than flush and do a soda treatment or two before filling for good. Should I be using a coolant instead of water? Been driving this car since 93 with no real rust problems before. (But then that's what the guy aid when his horse died, "Never did that before.")

"Should I be using a coolant instead of water?"

Where you drive, in my opinion, no.

Your engine would not run rust free for 23 YEARS and suddenly form rust out of the blue without good reason. Mr. Wesenberg explained it exactly. Rust had formed and settled in the back years ago when people were running straight water in your engine and it finally broke loose. Rust will not form in a proper ratio mix of soluble oil and water. In your case the rust was already there and mixed in when it came loose.

On the other hand, an oil/water mixture that is too weak can form rust just as a weak mixture of antifreeze to water can form rust. Seen it all my life.