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      01-05-2019, 03:29 PM   #2
nachob
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Drives: 2004 330i ZHP, 2022 Cayman T
Join Date: Apr 2008
Location: California

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Not normally. Cars have evaporative controls to let the gas expand and so it doesn't go into the atmosphere. They have little expansion tanks for this. It's possible under pressure a little bit might end up in the evaporative system but not enough to move the gauge. When the car is moving around the gauge doesn't move immediately. It's possible it was slightly higher when you drove it in because you were driving it around. Once it settled for a few weeks, it dropped to the perfectly still level which is slightly lower than when the car is moving. Just a shot in the dark!
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