Review on Standard Motor Products DCV1 Check by Shawn Pollock

This solved my problem. My old check valve no longer held a vacuum. I diagnosed my problem by blowing air through the black and white sides. None of the routes will be closed. This causes my air conditioning to switch from the dash to blowing through the defroster vents when driving uphill. Also, if you're sitting at a long red light, the air on the dashboard will start blowing warm air. Here are the full dimensions measured with a digital caliper: This vacuum check valve has 5mm O.D. tubes. The teeth have an outer diameter of 5.8 mm. The overall length from start to finish is 43mm. Outer diameter of the valve body 19 mm. The black side should be aligned (pointing) with the vacuum side (motor side).