Audi Parts Catalog Audi Accessories Catalog Audi Technical Articles VW-Audi Tech Forums
 
  Search our site:    
View Recent Cars  |   Cart  | Project List | Order Status | Help    
 >  >
Audi Air Filter Replacement
 
Bookmark and Share

Pelican Technical Article:

Audi Air Filter Replacement

Peter Bodensteiner

Time:

30 mins.

Tab:

$13

Talent:

**

Tools:

screwdrivers

Applicable Models:

Audi A4 (1997-01)
Audi A4 Quattro (1997-01)
Audi TT (2000-04)
Audi TT Quattro (2000-04)
VW Beetle (1999-02)
VW Golf (2000-02)
VW Jetta (1998-05)
VW Passat (1996-00)

Parts Required:

New filter

Hot Tip:

wipe out the air filter housing with a rag

Performance Gain:

Better breathing engine

Complementary Modification:

Change cabin air filter

Changing the filter that protects the engine's intake tract from dust and debris is usually more challenging in modern cars than in older cars. Rather than simply spinning a wing nut off and on, cramped engine bays and multiple lines and connections mean you usually have to contort your fingers to get at hidden fasteners and then muscle various hoses, housings and other parts out of the way in order to change an air filter. The Audi A4 is no different.

Although it doesn't change much about the process of replacing the air filter, it's worth making note of the 1.8T's intake path, which is different than that of a conventional car because of its turbocharger and intercooler system.

In a naturally aspirated car, air goes from intake snorkel to filter to throttle body to intake manifold to engine. In a turbocharged car, the air that passes through the filter instead travels to the compressor side of the turbocharger. The compressor wheel is attached by a shaft to the turbine wheel of the turbo, which is propelled by exhaust gases coming out of the engine. Thus the turbo uses exhaust gases to spin the compressor wheel and compress the intake air; the turbo is usually located near the exhaust side of the engine.

In our Audi 1.8T, the intake air travels through a snorkel that takes air from the front grille area to the passenger side of the engine compartment. The air enters the bottom of the air filter housing, flows up through the filter and then down through a hose to the turbocharger. The turbo is mounted to the exhaust manifold on the passenger side of the engine.

After the intake air is compressed by the "cold" side of the turbocharger it travels across the front of the car to the intercooler, which is mounted just ahead of the driver's side wheel well. Then it goes through the throttle body, intake manifold, and into the engine.

The air filter housing is like a clamshell, divided into upper and lower halves. The upper half is freed up by releasing four clips, after which it can be raised to gain access to the filter itself.

Here's what you'll find when you open the hood of your 1.
Figure 1

Here's what you'll find when you open the hood of your 1.8T. The filter housing is located underneath this panel, which is purely cosmetic. The intake snorkel is the piece with the ribbed section just in front of this cosmetic panel.

The underside of the cosmetic panel has two triangular plastic wedges that snap into corresponding metal clips on top of the filter housing.
Figure 2

The underside of the cosmetic panel has two triangular plastic wedges that snap into corresponding metal clips on top of the filter housing. Here I've tilted the upper panel to show the relationship between these connecting pieces.

Once you remove the upper panel, here's what you'll see.
Figure 3

Once you remove the upper panel, here's what you'll see. Note the proximity to the exhaust manifold to the right in this photo. You'll want to make sure the engine is cold before performing this filter change, because you'll be working right next to the exhaust system and you could get burned quite easily.

No crazy fasteners for the intake snorkel.
Figure 4

No crazy fasteners for the intake snorkel. Just pull up here, where it joins with the air filter housing ...

.
Figure 5

...and at the front, simply pull it away from the duct that brings air in from the grille area, above the radiator.

This is the view back through of the fresh-air duct toward the front of the car.
Figure 6

This is the view back through of the fresh-air duct toward the front of the car.

There are four clips that hold the upper half of the air filter housing tight to the bottom half.
Figure 8

There are four clips that hold the upper half of the air filter housing tight to the bottom half. This one at the front right corner is the most visible and accessible. The right rear clip, which has been released, is also visible in the photo. All four clips have this same design and are released by pushing the top tab off of the edge of the upper housing.

Now the degree of difficulty increases; this clip is located on the left rear side of the filter housing.
Figure 9

Now the degree of difficulty increases; this clip is located on the left rear side of the filter housing. It's not that hard to release once you get your hand on it, but you have to wedge your hand in behind the heat shield to get to it (green arrow).

Remember that heat shield from the last step? Do yourself a favor and remove the two Phillips screws holding the top of it in place.
Figure 10

Remember that heat shield from the last step? Do yourself a favor and remove the two Phillips screws holding the top of it in place. You can then tilt it out of the way, which will help you reach clip number 4, on the left front corner of the airbox.

Here's a look at clip number 4.
Figure 11

Here's a look at clip number 4. You can see how, once you move the heat shield out of the way it's much easier to reach (green arrow).

If you still can't reach that last clip, you can remove move the turbo intake tube from the airbox.
Figure 12

If you still can't reach that last clip, you can remove move the turbo intake tube from the airbox. This step may also help you move the top of the intake housing in order to get at the filter. Loosen the hose clamp with a nut driver, screwdriver, or ratchet.

Wedge a screwdriver between the hose and the airbox in order to break its hose's seal and release it from the airbox.
Figure 13

Wedge a screwdriver between the hose and the airbox in order to break its hose's seal and release it from the airbox.

Pull the turbo intake hose out of the way but make sure nothing falls in; this hose provides a direct path to the compressor side of the turbo.
Figure 14

Pull the turbo intake hose out of the way but make sure nothing falls in; this hose provides a direct path to the compressor side of the turbo.

Now you can lift the upper air filter housing up and away from the lower half.
Figure 15

Now you can lift the upper air filter housing up and away from the lower half.

Reach in and extract the old filter.
Figure 16

Reach in and extract the old filter.

Comparing the new filter, on the right, with the old one, it looks like the old one isn't really that old.
Figure 17

Comparing the new filter, on the right, with the old one, it looks like the old one isn't really that old.

Here's a good look at what you have to work with when installing the new filter.
Figure 18

Here's a good look at what you have to work with when installing the new filter. Be assured that it is harder to get the new one in than it was to get the old one out!

The new filter goes in pleat-side down.
Figure 19

The new filter goes in pleat-side down. This photo shows the kinds of obstacles you'll face when wrestling it into place.

Here the filter is largely in position.
Figure 20

Here the filter is largely in position. At this point you can lift the upper half of the housing and the filter up, rotate it slightly to make it parallel to the lower half, and then lower it straight down into the bottom half.

The remainder of the job consists of buttoning everything back up.
Figure 21

The remainder of the job consists of buttoning everything back up. This shot illustrates again why you want to do this job with a cold engine--that's the exhaust oxygen sensor pressing against my hand as I secure the left rear clip.

22
Figure 22

Fasten the other three remaining clips; reattach the turbocharger hose to the airbox; secure the heat shield with the two Phillips screws; and reattach the intake snorkel and cosmetic airbox cover.

Bookmark and Share
Comments and Suggestions:
Joe Comments: Thanks for the advice lat me try all that and I will come back to you
November 2, 2015
  Followup from the Pelican Staff: No problem. - Nick at Pelican Parts  
Joe Comments: On hot day or after long distances my car will just cut out and I will have to wait about ten minutes before it can start again. Mechanics adived me to replave the fuel sensor but that didnt help too.
November 1, 2015
  Followup from the Pelican Staff: When your engine doesn’t start you’ll want to check the basics. Check spark, fuel injector pulse and fuel pressure, volume, quality and engine compression. Are there any fault codes? Once you figure out what is missing, it will be easier to diagnose.
- Nick at Pelican Parts
 
i can fix it Comments: thank you! i replaced the deteriorated foam piece with an old sock...it seems to work - i'll know more when i check the mpg next.
April 4, 2015
  Followup from the Pelican Staff: Thanks for the follow up. We appreciate it.
- Nick at Pelican Parts
 
i can fix it Comments: ...here it is, from a weird angle. i also meant 'air filter, not 'oil filter' when referencing mpg improvement. thank you so much - i bought the hayes manual, but it's not working for me. i knew better. may as well throw in a suggestion for a good manual, too, if you have one. thanks again! e
April 2, 2015
  Followup from the Pelican Staff: That is the fresh air flap. It opens at certain engine speeds. - Nick at Pelican Parts  
I can fix this! Comments: What is the valve looking thing underneath the air filter on a 2003 passat wagon 1.8 t? Also wondering what the best path to take is for someone interested in improving mpg while changing oil filter....i.e. Brand/type/conversion? Thanks, Erin
April 2, 2015
  Followup from the Pelican Staff: Inside the intake air housing? I think there is only the snow screen inside. Can you share a photo? - Nick at Pelican Parts  

  Search our site:    

View Cart & CheckOut | Project List | Order Status |  Help    

 

[Home] [Customer Service] [Shopping Cart] [Project/Wish List]
  [Privacy Statement]  [Contact Us] [About Us] [Shipping] [Careers]

Copyright © Pelican Parts Inc. -    DMCA Registered Agent Contact Page

Page last updated: Fri 12/9/2016 02:01:54 AM