In the early years of automotive history, vehicles were equipped with few accessories. In the beginning, a leather – not rubber – belt drove just the cooling fan. As time went on and vehicles became more complex, more belt-driven accessories appeared on engines and the nylon-reinforced rubber belt replaced the leather belt. The 2007 VW Jetta came standard with a 150-horsepower, 2.5-liter in-line five-cylinder engine, which had three belt-driven accessories and used two drive belts to run them. Replacing the alternator belt, which also drives the power steering pump, requires removing the air-conditioning compressor belt first.
Loosen the lug bolts on the passenger’s front wheel with a ratchet and socket. Raise the front of the Jetta with a floor jack and slide jack stands under the front suspension crossmember. Lower the vehicle onto the jack stands. Remove the lug bolts and pull the wheel off the Jetta’s hub.
Crawl under the vehicle and remove the under-engine splashguard by removing the eight screws – four on each side – with a ratchet and socket, then pulling the splashguard rearward to disengage it from the bumper cover, then down.
Remove the 11 bolts securing the right-side engine splashguard found in the passenger’s side wheel well, then remove the right-side engine splash guard, exposing the drive belts behind it.
Draw a diagram of how both drive belts route over the accessory pulleys, using a pen and paper. This will aid you in reinstalling the belt.
Draw an arrow on the air-conditioning drive belt, using a grease pen, pointing the direction that the belt rotates when the engine is running. This helps you install the belt facing the same direction.
Find the air-conditioning tensioner pulley, between the crankshaft pulley and the air-conditioning pulley, by looking through the wheel well. Place a ratchet and 15 mm socket on the bolt in the center of the pulley and rotate the pulley clockwise to relieve tension from the belt and hold it there, then pull the belt off its pulleys. Allow the tensioner to rotate slowly back into its resting position.
Inspect the air-conditioning belt for any defects, including cranks, splits, fraying or missing grooves. If any defects exist, replace the belt.
Look above the air-conditioning tensioner pulley and find the alternator belt tensioner pulley. Rotate this pulley clockwise with a ratchet and 15 mm socket to relieve tension from the alternator belt and hold it. Remove the alternator belt from all the pulleys it drives. Allow the tensioner pulley to rotate slowly to its resting position.
Route the new alternator pulley around all of the pulleys it drives, except the tensioner pulley, using the diagram you drew as your guide. Rotate the tensioner pulley clockwise with a ratchet and 15 mm socket. Align the alternator belt up with the tensioner pulley, then allow the tensioner to rotate counterclockwise slowly until it engages the belt. Remove the ratchet and socket.
Use your drawn guide to reinstall the air-conditioning belt onto all of the pulleys it drives, except the tensioner pulley. If you are using the old belt, face the arrow you drew on it in the same direction it was pointing before you removed it. Turn the tensioner pulley clockwise with a ratchet and 15 mm socket, then align the belt with the tensioner pulley. Allow the tensioner to rotate slowly counterclockwise until it contacts the belt.
Reposition the right-side engine splashguard into the wheel well and hand-thread its 11 retaining bolts. Tighten the retaining bolts to 2 foot-pounds with a torque wrench and socket.
Crawl under the vehicle and lift the under-engine splashguard into place. Slide the splashguard forward until the tabs on the front of the splashguard engage the lip on the bottom of the front bumper cover. Hand-thread the eight under-engine splashguard bolts, then tighten them to 2 foot-pounds with a torque wrench and socket.
Install the front wheel onto the Jetta’s front hub and hand-tighten its wheel bolts. Raise the vehicle off the jack stands with a floor jack, then remove the jack stands. Lower the Jetta to the ground. Tighten the wheel bolts, in a crisscross pattern, to 89 foot-pounds.
