Piston Slap: Truncated Thoughts on Trunk Vents

Sajeev Mehta
by Sajeev Mehta
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.

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2 of 74 comments
  • Hawox Hawox on Feb 26, 2016

    some years ago fiat was forced to pay damages to some lancia dedra owners. trunk vents were located above the tail pipe, the evidence was that exaust gasses were sucked in the compartment. i don't know it properly but some cancer cases were proved caused by exposition to the dedra's exaust

  • 415s30 415s30 on Mar 10, 2016

    I know on the early 240Z they changed the vents around because people's ears would pop, and the rear ones also sucked in exhaust. I would think pressure and the flow of air in all driving conditions with the windows up or down etc.. would make pretty significant changes.

  • Inside Looking Out All that is BS. Nissan just tries to buy time. By 2028 every Tesla will have fusion reactor under the hood. Commercial fusion reactor is under development as we speak 5 miles away from my home in Sandia labs in Livermore.
  • Lou_BC For some odd reason my new truck is more of a pain when it comes to incoming texts. I need data activated on phone and have it plugged into truck with Android Auto on. It doesn't work well with poor internet wireless access.The old Ford Sync system of 2010 vintage would play the text via a robotic voice and not allow a reply unless stopped. It was much more seamless and easier to work.
  • 28-Cars-Later Isn't that the Cayenne?
  • Kendahl I will look at my phone long enough to determine whether the caller is someone I really should talk to. If it is, I keep driving until I find a safe place to pull over before answering. If it isn't, to hell with them.I am greatly annoyed by people who sit at green traffic lights or drive well below the speed limit because they are focused on their phones instead of their driving. However, I don't express my frustration because (1) they don't think they're being inconsiderate and (2) may retaliate with road rage.
  • VoGhost What to name a car for people insecure about the size of their 'manhood'? Magnum. What do name a car for people insecure about their orientation? STR8. Nobody -- and I mean nobody -- knows their customer base like FCA/Stellantis.