Maybe you are right...I know I checked my vacuum pods about 6 months ago (i replaced them all 2yrs before) and they were fine but I was getting air out the defrost vents which I read should not be happening. I guessed it could be the vacuum bypass unit that all the hoses attach to. Maybe in addition to the defrost vents not closing it could be leaving me at 80% instead of 100%...

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k