[0w40X1]

When I ran my X1 s28i without air conditioning one nice day, I thought something was really wrong. The coolant temp on my scanguage showed 236 deg f instead of the 215 deg f I was used to.
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The second you add gas, temp starts down.

In fact when on the track car runs cooler at 209 deg f.

Using eco-pro, temp goes up to 236 deg f.

So when there's nopt much waste heat, BMW design adds heat on purpose for efficiency.

21 extra deg f COULD make plastic more brittle, and I see no need for that slight almost immeasurable economy.

Most all those Japanese cars don't get much better mileage with way less power.