Cleaning the Plenum


My girlfriend purchased a new 2018 Audi Q5, from this dealer. When it was in for standard maintenance they tried to tell her the “plenum needed cleaning”. They wanted $200 for this service. I advised against it. When she got it home, we found leaves covering the plenum but nothing inside the venting. Brushed them off. Thoughts?

thats not the plenum. thats the cowl. the plenum is under the plastic cover with the audi symbols.


Why do they think it needs to be cleaned, and how do they do it? Any direct injection car needs periodic cleaning of the injection valves since the fuel can’t do that any more. This may be what they suggest, and 3 years is a reasonable time for that service.


That picture makes me think that no one is raising the hood to check the oil level or other fluids on a regular schedule . Might be a good idea for both of you to learn how to check things and tire pressure and rotation .


I stand corrected. I never heard that area called a plenum but…


Posted on: May 9, 2018Audi Car Logo

It’s not always easy keeping up with all the maintenance tasks associated with driving a luxury import vehicle such as an Audi ; however, in order to experience your car at the performance level it was intended, such maintenance tasks are critical. Maintenance procedures range in cost, difficulty, and frequency, which make some procedures easier to put off than others. One task that you shouldn’t put off in your Audi is caring for the plenum tray located beneath the windshield in your car.

If you have no clue what a plenum chamber is, then you’re in luck—this article will briefly go over the common problems in Audi vehicles associated with a clogged plenum tray , including what models encounter the issue the most, and some of the consequences of not addressing the issue. The most important thing we’ll talk about is how to prevent a clogged plenum tray in your own Audi.


Your Audi is designed to be able to withstand various weather patterns, including heavy rains or exposure to excessive moisture. The plenum tray is a part under the hood toward the cabin with the main function of draining the water and moisture your car can collect. The intricate system of drainage components, including different valves , hoses , and filters , is ripe with areas for potential failure and, unfortunately, many Audi drivers tend to encounter a clogged plenum tray at one point or another.


The most common Audi model that deals with clogged plenum trays is the Audi A4 Quattro , across decades of engineering and design—that means that even if you drive an older Audi A4 , you’re even more susceptible to plenum tray clogs. Since this issue is common in specific Audi vehicles over others, it’s best to bring your car to an Audi specialist who will be able to accurately diagnose, assess, prevent, and treat any problems.


A clogged plenum chamber is known to lead to other significant performance issues in Audi vehicles, and therefore must not go overlooked in common maintenance procedures. Some of the most commonly associated problems include:


Water leaking into brake components can lead to premature wear of the parts, including corrosion and rust. This can lead to expensive brake repair procedures that otherwise might not have been necessary until much later in the car’s life.


As we all know, electrical components and water don’t mix well. When water comes into contact with electrical parts, it can cause wiring to short out and electrical currents to seize communication with terminals. This is problematic, as it can lead to HVAC issues as well as other concerning problems in your Audi’s performance.


One thing that Audi drivers especially pride themselves on is the luxury and comfort of the interior cabin . When the plenum drain becomes clogged, it is common for drivers to notice water seeping into the cabin, especially beneath where the HVAC blower is located. This can create mold and mildew growth inside the cabin or even extensive water damage, requiring significant repair work to fix the issue.


The best way to prevent your Audi’s plenum trays from clogging is to continually perform inspections and maintenance. If you’re not comfortable assessing your car’s draining on your own, it is imperative that you bring your Audi to an Audi specialist to ensure the best quality of care. Keeping the plenum tray free of debris such as leaves and dirt is a good way to ensure optimal drainage at all times, especially during the autumn season when leaves fall more rapidly in greater volumes.

Black Audi Q5 S-Line


The Audi experts here at Orion Automotive Services help make us the leading dealership alternative in Ann Arbor, MI , for such European imports. We take pride in our honesty, integrity, and excellent customer service, all of which have contributed to our standout reputation in the community; however, our level of skill, expertise, and knowledge make us the most qualified shop in Ann Arbor to work with such sophisticated automobiles. If you think you’re experiencing drainage problems in your Audi, the problem could be related to a clogged plenum tray. Please contact one of our helpful staff members to schedule an inspection right away, as the continued quality of your Audi’s performance depends on immediate, professional attention.

** Audi Logo image credit goes to:* vesilvio.

** Black Audi Q5 S-Line image credit goes to:* NikWaller.




Must have taken a lot of engineering to get a clogged AC drain to affect braking.


I think plenum is kind of a generic term. Intake plenum. AC plenum, etc.

Yeah, I think the OP means the intake manifold, not the debris cover.

?? The plenum in this case is the intake area for the HVAC system, under the debris cover (where the leaves are in the pic), I think.

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It doesn’t need to be opened because the car has no dipstick. Oil level is checked from the display screen inside the car.

Actually I am quite good at checking these things including changing my own oil in my 2018 Audi Q5 (my vehicle is garaged in Savannah, hers is in NYC). The service manager referenced the leaves in his report. I brushed off the leaves and removed the covers on both sides. Everything appeared to be very clean under the covers. The vehicle is still under warranty and if this is a recurring design problem, Audi should fix it.

Once it’s out of warranty I might find a way to put window screening over the area, to keep out all but the smallest stuff. Works great on my house’s outdoor A/C condenser, keeps out all the cottonwood seeds.

Mines not an Audi but looks familiar…

  1. Weekly shop vac of that area before washing.
  2. Annual removal of screen for vac and clearing of the drain hoses with air, then water.
  3. Annual cleaning of the air box/cabin filter area.

Still had to replace a cabin blower motor due to rust from accumulating stuff and moisture but that’s not bad for 10 years and over 150,000 miles.

Sounds like $200 well spent given given @weekend-warrior response

I think the main reason for the posted article is ADP, additional dealer profit. After all, $200 for brushing off a few leaves is pretty sweet. I would gladly do it for $100.

My daughter’s old car was sitting for several months before it was sold. Before we sold it, I opened the trunk and hood. There were lots of leaves in the channels, and I removed them. I should demand a couple hundred bucks for that! I even put them in a bag and not on the ground!