In 1980, Volkswagen released a sedan version of its compact Golf, and named it the Jetta. At the time of publication, the Jetta had undergone five generational changes, with the latest starting in 2005. The 2007 Jetta came in five trim levels, they were: base, 2.5, Wolfsburg Edition, 2.0T and GLI. The Wolfsburg Edition came fitted with a 150-horsepower, 2.5-liter four-cylinder engine. Volkswagen integrated the air filter housing with the plastic cover on top of the engine, making replacing the air filter slightly trickier.
Open the Jetta's hood, and find the two bolts securing the end of the air intake tube to the front grille. Remove these bolts, using a ratchet and socket.
Trace the air intake hose toward the engine until you find the mass airflow sensor -- the electrical component attached to the air intake tube. Squeeze the ears on the hose clamp securing the air intake hose to the MAF sensor using slip-joint pliers, and slide the hose clamp away from the MAF sensor. Pull the air intake hose from the MAF sensor, and set the intake hose in a secure location.
Press the locking button on the MAF sensor wiring harness, and pull the harness away from the MAF sensor.
Grab both sides of the front part of the plastic engine cover and pull it upward to disengage the front retaining clips. Grab both sides of the rearmost part of the plastic engine cover, and pull upward to disengage the retaining clips. Pull the cover off the engine, and set it upside down on a soft surface.
Find the air filter housing on the underside of the engine cover. Remove the five air filter housing screws, using a Phillips screwdriver. Pivot the front of the air filter housing upward and pull the housing off the tabs on the engine cover.
Pull the air filter out of the housing -- take note of the filter's positioning for reinstallation. Slide a new air filter into the housing in the same position as the old filter.
Guide the air filter housing onto the underside of the engine cover, so the tabs on the engine cover slide into the slots on the rear of the air filter housing. Pivot the air filter housing downward, and tighten the air filter housing screws with a Phillips screwdriver.
Set the engine cover back on top of the engine, lining up the retaining clips on the bottom of the engine cover with the slots in the engine cover brackets. Press the rearmost part of the engine cover down to lock the clips in place and then press the front part of the engine cover down to lock the front of the cover in place.
Press the air intake hose back onto the end of the MAF sensor. Move the hose clamp on the MAF sensor side of the intake hose back into place to secure the MAF inside the air intake tube, using slip-joint pliers.
Line the boltholes on the free end of the air intake hose up with the boltholes in the front grille. Tighten the air intake hose-to-grille bolts, using a ratchet and socket.
