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Does coolant evaporate?

March 11, 2019, 07:57:36 pm

We've been parked here since early January and are getting ready to leave at the end of the week. I've started doing some of the outside stuff and checked the coolant level. When we arrived in January the coolant in the white expansion tank was right at the COLD level. Yesterday if was quite a bit below that mark. I added enough to bring it up to the mark again (probably about a quart of 50-50 mix). I don't see any evidence of it on the ground, so where did it go? Engine oil is right where it ought to be 400 miles after an oil change and looks like it ought, as far as I can tell color.

We're in Hobbs, NM, so definitely a desert climate. Could it just be evaporation?

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Re: Does coolant evaporate?

Reply #1 – March 11, 2019, 08:01:24 pm

Well, the water component will certainly evaporate over time, which would lower the level.  Don't know about the antifreeze chemicals...

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Re: Does coolant evaporate?

Reply #2 – March 11, 2019, 08:02:59 pm

That's kind of what I was thinking, but Chemistry was more than 50 years ago and I've slept since then.

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Re: Does coolant evaporate?

Reply #3 – March 11, 2019, 08:11:00 pm

I'm in 'dry country' too, and lose some, but I don't know if the PO just added distilled water.  I'm going into Phoenix soon and will get what CAT suggests. I see no evidence of leaks, either.

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Re: Does coolant evaporate?

Reply #4 – March 11, 2019, 08:17:14 pm

Look for seepage around the radiator. Is it original?

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Re: Does coolant evaporate?

Reply #5 – March 11, 2019, 08:52:41 pm

From my experience, I suspect you have a small leak somewhere.  I have found some clamps that needed to be tightened.

Rich

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Re: Does coolant evaporate?

Reply #6 – March 11, 2019, 08:57:09 pm

I am also betting on a little seepage.  Cold temperatures, metal contracts and small leaks.  Check all hose clamps.

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Re: Does coolant evaporate?

Reply #7 – March 11, 2019, 09:32:05 pm

'When you arrived in January' was the engine warm or very cold. Warm engine coolant expands, cooling sucks it back into pressure tank if pressure cap is working ok. Coolant level should not go down once the coolant system has cooled down.

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Re: Does coolant evaporate?

Reply #8 – March 11, 2019, 09:33:54 pm

Coolant and oil checks are always done with the engine cold. Aside from getting proper readings, it is much easier on fingers.

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Re: Does coolant evaporate?

Reply #9 – March 12, 2019, 06:25:46 am

Check the coolant with a Refractometer. If the coolant concentration is up it's just water evaporation. Aqua-Hot's  evaporate water quite regularly if used consistently.

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