Piston Slap: Truncated Thoughts on Trunk Vents

Sebastian writes:

Every time I see a car on the street without its rear bumper, I see these vents under where the bumper is supposed to go. I have an Oldsmobile Cutlass Supreme 1993 that also has these vents inside the rear doors.

What is the function of those vents?

Sajeev answers:

I was shocked at the number of forum threads discussing trunk vents: people really wanna seal them up, too! More advanced Googling netted this great article, and here’s the good part:

The flow of air from the passenger compartment to the trunk compartment is desirable for several reasons. It is desirable that there be positive air pressure within the passenger compartment to cause air to go through the trunk compartment so that the trunk compartment, which is typically neither heated or cooled, maintains a temperature closer to the selected temperature of the passenger compartment. It is desirable that the passenger compartment have a higher air pressure rate than the trunk so that fumes, moisture or odors which may enter into the trunk from either outside the vehicle or from things stored inside the trunk do not enter into the passenger compartment.

To allow for the continuous flow of air from the passenger compartment into the trunk compartment, an exhauster must be provided. An exhauster is a vent that acts as a check valve to relieve air that is delivered into the trunk compartment from the passenger compartment to the exterior of the vehicle. Additionally, the exhauster also functions to relieve pressure when the doors, trunk or cargo hatch of a vehicle are closed. The pressure relieving function of the exhauster is vital to passenger comfort and to the prevention of glass damage to the vehicle.

So yeah, these things are important. That’s all we can say … right, Best and Brightest?

[Image: Shutterstock user aliciamariemassie]

Send your queries to sajeev@thetruthaboutcars.com. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice.