The fourth generation Volkswagen Jetta came with two distinctive engine types, the 1.8-liter 20 valve turbo 4 cylinder and 5 cylinder VR5 powerplant. Manufactured between 1999 and 2005, there’s lots to like about this cool sedan but there’s also list of concerns when you begin to modify your Jetta.
Want more power and torque in your turbocharged engine but not sure how to get it safely? one of the best modifications is a Volkswagen Jetta cold air intake. Today we’ll be showing you how to install one in a 2003 Jetta Wolfsburg edition.
The part number for this cold air system from AEM is 21-493 and it comes in a variety of colors from RED, BLUE, POLISH and GUNMETAL. This makes it easy for you to add a dash of flavor to your engine bay, and increases the efficiency of your engine.
How is this done? AEM’s Dryflow open air element is mounted under the front driver side fender, and routes fresh cold air into your engine. The colder the incoming air charge, the denser the air is and thus the more power you can make. This increases combustion capabilities and creates for a happier, more efficient fuel combustion cycle.
Tools you will need to install this AEM cold air intake
- automotive jack – optional
- 10mm / 8mm sockets
- long extension
Before you begin make sure to use care around your coolant hoses. The Jetta’s engine coolant hoses are plastic and the heat created from the turbocharger and piping can lead to them becoming brittle over time. To begin installing your air intake, you must first undo the airbox in your Jetta by unscrewing the 10mm bolts that secure it to your chassis.
The air box is a small unit located above your battery tray, and the distribution block that’s mounted to the top of it.
Undo the clamps that lead to your Volkswagen Mass Air Flow Meter (MAF) and remove the entire airbox assembly. Now that you have your air filter removed, pull up on the plastic covering over your battery distribution box.
In order to install your Volkswagen Jetta Cold Air Intake, you must remove the battery all together. There’s a small opening near the fenderwell and with the battery in place there’s no way to snake in the AEM intake.
Begin this process by undoing the distribution block, and undoing the battery terminals on your battery posts. The next part is to loosen the battery by removing the tricky bolt behind your front driver side headlight. This is a 11mm bolt that secures the back end of your battery tray to the chassis.
Once this bolt is removed you can move on to disconnecting the front battery tie down in your Jetta, and removing the entire battery all together.
Now that’s out of the way, move onto your MAF and unplug it by pulling up on the retaining clip.
Now that the MAF is unplugged, you should have enough wiggle room to fit your AEM cold air intake pipe through the opening in your Volkswagen fenderwell. Before you do that however, you must secure the lower pipe to the AEM DryFlow filter and use one of the supplied 10mm grommets to screw into your frame.
You can get away with this without the use of a automotive jack, but always use jackstands if you are going that route.
Once you have the AEM filter and lower pipe secured, it should be mounted securely and safely, with the opening facing upward.
Always make sure to use the supplied AEM grommets for any mounting to the chassis and the intake pipe.
Next you must remove the PCV inlet to your valve cover, and carefully install the rubber hose supplied by AEM.
Once you have the new PCV hose connected to the upper AEM cold air intake pipe, you are ready to go. Connect the lower pipe to your MAF and tighten up the LOWER hose clamps for a snug fitment.
Make sure to tighten the LOWER clamps only to ensure your air intake isn’t going anywhere. Once it’s in there nice and snug you can reconnect your MAF. There’s one last grommet you need to mount to the fender to make sure the AEM intake isn’t going anywhere.
Use the supplied AEM grommet here, it’s also a 10mm but DO NOT TIGHTEN until after everything is in and together.
Once your MAF is reconnected, go ahead and put back the battery carefully, it may be a tight fit.
Because the Jetta uses a dedicated battery tray, there’s very little wiggle room. Because of this, do not tighten the hose clamps leading to your mass air flow sensor, as these are best left loose. If your intake pipe doesn’t fit right, you might need to rotate or clock it for better fitment.
Reinstall your battery and secure the front 11mm bolt first, then you can go about putting back the battery isolation plastics and reconnecting the battery terminals. Make sure to put back the battery distribution block as you found it, otherwise the master battery cover won’t fit right.
Once the battery is reconnected, tighten the clamps to your MAF and the 10mm grommet that’s on the driver side Jetta fender. Congratulations! you now know how to install a Volkswagen Jetta Cold Air Intake!
Have any questions about our guide? Leave us a comment below and let us know!