Complementary Modification: Replace Belt Tensioner
One of the more routine maintenance jobs you will encounter while owning a E46 involves replacing the drive and serpentine belts.
That dreaded "gravel-like" sound hitting the under tray of your 3-Series, followed by the loss of power steering and an increasing engine temperature gauge usually indicates your serpentine belt has snapped. If you have had this happen to you and have diagnosed either belt to be the culprit, then read on.
In this article, I'll go over the steps involved with replacing the drive belts on the BMW E46, M52 and M54 engine. Be sure to always remember to work with a cool engine, you DO NOT want to be working in or around hot metal components! Also remember to remove the key from the ignition.
Hot tip
Work with a cool engine.
//
Project Photos
Figure 1 The BMW E46 models utilize 2 multi-rib engine drive belts. A small outer belt drives the A/C compressor and the larger inner belt drives the alternator, coolant pump and the power steering pump.
Figure 2 With your engine cold and off, inspect your drive belts for wear. The belts (outer belt red arrow, inner belt yellow arrow) should be free from cracks, fraying, glazing and missing chunks. Replace your belt every four years or if any of the previously mentioned issues are present.
Figure 3 Working at top of radiator, remove the 4 expansion rivets from the intake air duct (yellow arrows).
Figure 4 To remove the rivets, you can use a small flathead screwdriver to pry them up, then, using needle nose pliers, pull the rivet out. The expanding portion of the rivet will now come out with the duct. Depending on your model year, the vehicle may have 3 or 4 expansion rivets.
Figure 5 Next, remove the intake air duct from your radiator support by lifting it up and out of the intake air housing duct. It is not necessary to remove the radiator cooling fan shroud from the vehicle. However removing it will allow easier access to the drive belts. See our Pelican Parts Technical Article on Removing the Radiator Fan for more instructions on how to remove. Before removing the drive belts, mark the direction of rotation (if reusing belts) and note the installation position. There are two styles of tensioners, hydraulic and spring (mechanical) loaded. Each has a unique way of releasing tension.
Figure 6 If you have hydraulic style tensioners, remove the dust cap (yellow arrow) from the tensioner pulley.
Figure 7 Once your dust cap is removed, youÂÂ'll have access to the 8mm Allen nut (red arrow) used to rotate the tensioner.
Figure 8 If you have spring loaded tensioners, use a 16mm hex socket (red arrow) to rotate and release the tension.
Figure 9 Locate your A/C drive belt tensioner; use a 16 mm hex socket (red arrow) or remove the dust cap (yellow arrow) to access the Allen bolt, if 16mm hex is not present.
Figure 10 Using a ratchet with a long handle and an 8mm socket or a 16mm open end wrench (yellow arrow, depending on style of tensioner), rotate the A/C belt tensioner clockwise to release tension and slide the belt (red arrow) off the pulleys.
Figure 11 Locate the accessory drive belt tensioner and remove the dust cap (if necessary). Using a ratchet with a long handle and the appropriate size socket, rotate the drive belt tensioner clockwise (red arrow) to release the tension and then you can slide your belt off the pulleys.
Got more questions? Ask any of our automotive experts.
