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Drive Belt Replacement
 
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Pelican Technical Article:

Drive Belt Replacement

Nick Czerula

Time:

2 hours2 hrs

Tab:

$40

Talent:

****

Tools:

Set of sockets, wrenches, screwdrivers

Applicable Models:

BMW Z3 (1996-02)

Parts Required:

Drive belt

Hot Tip:

Work with a cool engine.

Performance Gain:

Proper engine accessory operation

Complementary Modification:

Replace idler pulley

The BMW Z3 engine utilizes two drive belts to drive the accessories pulleys at the front of the engine. The power steering pump, coolant pump and alternator are driven by one belt. A separate belt drives the AC compressor. A tensioner pulley tensions each belt. In some models an engine- cooling fan mounted on a thermal clutch is also driven by one of the drive belts.

The belts are tensioned by strong tensioners and do not need periodic adjustment. But they will, over time and due to heat, cold and the rigors of operating multiple pulleys, develop signs of wear. The signs of wear include: cracks, fraying, glazing or missing chunks. In addition, the tensioners and idler pulleys may develop defects. Bearings in these pulleys are lifetime lubricated. The lubrication eventually dries up or wears out and may cause noises. If a pulley bearing deteriorates, it can tilt and allow the belt to fly off the pulleys. If it seizes it can damage the belt quite quickly due to excessive friction.

In this article, I'll go over the steps involved with replacing the drive belts on the BMW Z3 4-cylinder engine and 6-cylinder engine. Be sure to work with a cool engine and remove the key from the ignition. With your engine cold and turned OFF, inspect your drive belts for wear. The belts should be free from cracks, fraying, glazing and missing chunks. Replace your belt if any of the previously mentioned issues are present or every four years.

Keep in mind that when your car was serviced before, parts may have been replaced with different size fasteners used in the replacement. The sizes of the nuts and bolts we give may be different from what you have, so be prepared with different size sockets and wrenches. 

Protect your eyes, hands and body from fluids, dust and debris while working on your vehicle. If you are working with the electrical system, disconnect the battery before beginning. Always catch fluids in appropriate containers and properly dispose of any fluid waste. Recycle parts, packaging and fluids when possible. Never work on your vehicle if you feel the task is beyond your ability. 

Models with 4-cylinder engine:

BMW Z3 models equipped with a 4-cylinder engine utilize 2 multi-rib engine drive belts.
Figure 1

BMW Z3 models equipped with a 4-cylinder engine 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 power steering pump. Some models have an idler pulley on the main drive belt and some do not. Use this diagram to aid with removing and installing your drive belt. Before removing drive belts, mark direction of rotation (if reusing belts) and note installation position. To remove the alternator (accessory) drive belt, you have to remove the A/C belt first. This is the order I will show you how to service the belts on your 4-cylinder Z3 engine. I like to remove the air filter housing, it makes access to the tensioner and belt much easier. Jack the front of your vehicle. See our tech article on jacking your vehicle.

Using a small flathead screwdriver, remove the tensioner dust cap.
Figure 2

Using a small flathead screwdriver, remove the tensioner dust cap. (green arrow). Gently lever off the cap by prying at edge.

The tensioner on the A/C belt is secured in position using a locking bolt (green arrow).
Figure 3

The tensioner on the A/C belt is secured in position using a locking bolt (green arrow). To relieve tension, loosen the 13mm bolt. Once this bolt is loosened, the tensioner will release and you can remove the belt.

Now you can remove the drive belt from the A/C compressor and pulley.
Figure 4

Now you can remove the drive belt from the A/C compressor and pulley. Next you will remove the alternator (accessory) drive belt.

Using a flathead screwdriver, loosen the secondary air pump inlet hose clamp.
Figure 5

Using a flathead screwdriver, loosen the secondary air pump inlet hose clamp. (green arrow)

Then remove the secondary air inlet hose from the air filter housing by pulling it straight off.
Figure 6

Then remove the secondary air inlet hose from the air filter housing by pulling it straight off. (green arrow)

Next, you will unclip the three air filter housing retaining clips.
Figure 7

Next, you will unclip the three air filter housing retaining clips. (green arrows). One of the clips was hidden beneath the secondary air inlet hose. You will have to reach in behind air filter housing to access it.

Disconnect the intake air sensor electrical connector by pressing the wire release tab and pulling the connector straight off.
Figure 8

Disconnect the intake air sensor electrical connector by pressing the wire release tab and pulling the connector straight off.

Working at the air flow meter, twist electrical connector counterclockwise to disconnect.
Figure 9

Working at the air flow meter, twist electrical connector counterclockwise to disconnect. (green arrow). Then loosen the air flow meter hose clamp (yellow arrow). Once loose, remove the air filter housing from the engine compartment.

Next, you have to loosen two 10mm nuts about 10 turns from the lower air filter housing (green arrows).
Figure 10

Next, you have to loosen two 10mm nuts about 10 turns from the lower air filter housing (green arrows). This will be enough to get it out.

With the lower air filter housing unbolted, lift it up, fastener side first, feeding the intake tube (green arrow) out of the shroud at radiator.
Figure 11

With the lower air filter housing unbolted, lift it up, fastener side first, feeding the intake tube (green arrow) out of the shroud at radiator.

Using a small flathead screwdriver, remove the tensioner dust cap.
Figure 12

Using a small flathead screwdriver, remove the tensioner dust cap. (green arrow). Gently lever off the cap by prying at edge.

To release tension on the belt, use a16 mm socket to rotate A/C belt tensioner counterclockwise and slide belt off pulleys.
Figure 13

To release tension on the belt, use a16 mm socket to rotate A/C belt tensioner counterclockwise and slide belt off pulleys.

Remove belt from alternator, then remove from remaining pulleys.
Figure 14

Remove belt from alternator, then remove from remaining pulleys. With belts removed, inspect pulleys for lateral play or binding. To install accessory drive belt, begin by wrapping belt around crankshaft pulley, then over and around water pump, pull a loop of belt through the crankshaft pulley and water pump pulley and place it around the tensioner. Then place the belt on the power steering pulley and around alternator. Release the tensioner, then install belt around tensioner pulley and tension belt. Check that it is properly aligned and installed in all pulley grooves correctly. Be careful not to force belt onto pulleys, damage may occur. To install A/C drive belt, begin by wrapping belt around crankshaft pulley, then onto A/C pulley, next place it on top of the tensioner pulley.

To tension the A/C belt, use a 10mm Allen (green arrow) and rotate tensioner counterclockwise to tension belt.
Figure 15

To tension the A/C belt, use a 10mm Allen (green arrow) and rotate tensioner counterclockwise to tension belt. While holding tension with Allen, tighten the 13mm locking bolt (yellow arrow). Reinstall dust caps on tensioner pulleys and install intake air housing. Start engine and allow it to run for less than 30 seconds, shut engine OFF and recheck belt installation.

Models with 6-cylinder engine:
BMW Z3 models equipped with a 6-cylinder engine utilize 2 multi-rib engine drive belts.
Figure 16

BMW Z3 models equipped with a 6-cylinder engine 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 power steering pump. Before removing drive belts, mark direction of rotation (if reusing belts) and note installation position. There are two styles of tensioners, hydraulic and spring loaded. Each has a unique way of releasing tension.

Hydraulic style tensioners, remove dust cap (yellow arrow) from tensioner pulley.
Figure 17

Hydraulic style tensioners, remove dust cap (yellow arrow) from tensioner pulley.

Once dust cap is removed, you have access to the 8mm Allen bolt used to rotate tensioner.
Figure 18

Once dust cap is removed, you have access to the 8mm Allen bolt used to rotate tensioner. (red arrow)

Spring loaded tensioners use a 16mm hex boss to rotate and release tension.
Figure 19

Spring loaded tensioners use a 16mm hex boss to rotate and release tension. ( red arrow)

Locate A/C drive belt tensioner (yellow arrow); use 16 mm hex boss (red arrow) or remove dust cap to access Allen bolt, if 16mm hex boss is not present.
Figure 20

Locate A/C drive belt tensioner (yellow arrow); use 16 mm hex boss (red arrow) or remove dust cap to access Allen bolt, if 16mm hex boss is not present. Using a ratchet with a long handle and an 8mm socket or a 16mm open end wrench (depending on style of tensioner), rotate A/C belt tensioner clockwise to release tension and slide belt off pulleys.

Locate accessory drive belt tensioner and remove dust cap (if necessary).
Figure 21

Locate accessory drive belt tensioner and remove dust cap (if necessary). Using a ratchet with a long handle and the appropriate socket, rotate drive belt tensioner clockwise to release tension and slide belt off pulleys. (red arrow) With belts removed, inspect pulleys for lateral play or binding. The idler pulley commonly fails, if this occurs the coolant pump will lose the drive belt and engine will overheat. Now is a good time to replace the idler pulley to prevent future problems. To install accessory drive belt, begin by wrapping belt around crankshaft pulley, then over and around power steering pulley, around alternator, around coolant pump and around tensioner pulley. Avoid running belt under idler pulley for now. Once the belt is properly installed on all accessories, release tensioner as described earlier and slide belt onto idler pulley. Tension belt and check that it is properly aligned and installed in all pulley grooves correctly. Be careful not to force belt onto pulleys, damage may occur. To install A/C drive belt, begin by wrapping belt around crankshaft pulley, then onto A/C pulley, next bring a loop of the belt toward tensioner, working through center of loop release tensioner as described earlier and slide belt onto tensioner pulley. Release tensioner and check that belt is properly aligned and installed in all pulley grooves correctly. Be careful not to force belt onto pulleys, damage may occur. Reinstall dust caps on tensioner pulleys and install intake air duct. Start engine and allow it to run for less than 30 seconds, shut engine OFF and recheck belt installation.

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Comments and Suggestions:
Tim Comments: Easy job to do,my 1996 Z3 was not equipped with the secondary air inlet hose per diagram/photo,also mine uses the extra idler,this may be an early production type,still it took less time than anticipated.Thx for the fast shippment.
May 18, 2016
  Followup from the Pelican Staff: Thanks for the additional info and feedback. We appreciate it.
- Nick at Pelican Parts
 
Hasch Comments: My 1999 Z3 Roadster with 2.5L engine uses 50mm Torx to rotate tensioner after removing the dust caps. Thanks for the technical article!
May 5, 2016
  Followup from the Pelican Staff: Thanks for the additional info and feedback. We appreciate it.
- Nick at Pelican Parts
 
de Comments: tnx
February 24, 2016
  Followup from the Pelican Staff: No problem. - Nick at Pelican Parts  
Mel Comments: Very informative and helpful! Thanks
December 22, 2015
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 

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Page last updated: Wed 12/7/2016 02:06:53 AM