mis3

A local auto shop sells a coolant testing kit. This device consists of a pump, a tube to suck in the coolant and a small reservoir to test the coolant.

Reading the instruction, this tester can determine the boiling point of The coolant. Did anyone try something like this? What should be the boiling point of the coolant.

dave2001auto

Those are just density measuring device. The freezing point is more important, especially if you live in a very cold area. Usually at 50% to 60% antifreeze give maximum protection.

mis3

The description did not say if it would measure the freezing point. I will check.

By the boiling point and freezing point, can we determine if there is ATF contamination?

sailorben

I wouldn't suspect so. ATF is an oil, coolant/antifreeze is water miscible. So therefore, they shouldn't mix in a way that would allow you to take a sample and see how much the mixing would have affected a boiling point of the whole coolant volume. Especially when the coolant itself is a mixture of antifreeze and water at varying concentrations. You'd end up with an O/W emulsion, which I believe is what the white sludge you see in the coolant tank is, when there is significant mixing.

If you want to be certain, and you can't see any sludge in the expansion tank, I'd suggest sending a sample off to a testing company.

mis3

I do not see any white sludge in the coolant reservoir. Color is light brown and nothing gluey.

The coolant was changed back in Oct-2011 when they changed the water pump and thermostat. I have driven maybe 50k miles after the coolant change. It's probably too early to change.

dave2001auto

The coolant is also has anti corrosion agents that goes bad and are not measured by the float tester. If the coolant fails the tester, it likely bad on the anti-corrosion. The newer mbz has an anti-corrosion pod that is expected to last 14 years if nothing goes wrong.
If you have ATF or oil in the coolant, something has gone wrong and needs fixing.