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Pelican Technical Article:

Drive Belt Replacement

Nick Czerula

Time:

2 hours2 hrs

Tab:

$150

Talent:

**

Tools:

Set of sockets, wrenches, screwdrivers, needle-nose pliers, 16mm Hex socket

Applicable Models:

BMW 323Ci Coupe/Conv (1999-00)
BMW 323i Sedan/Wagon (1999-00)
BMW 325Ci Coupe/Conv (2001-06)
BMW 325i/xi Sedan/Wagon (2001-06)

Parts Required:

Drive belt

Hot Tip:

Work with a cool engine.

Performance Gain:

Proper engine accessory operation

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.

The BMW E46 models utilize 2 multi-rib engine drive belts.
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.

With your engine cold and off, inspect your drive belts for wear.
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.

Working at top of radiator, remove the 4 expansion rivets from the intake air duct (yellow arrows).
Figure 3

Working at top of radiator, remove the 4 expansion rivets from the intake air duct (yellow arrows).

To remove the rivets, you can use a small flathead screwdriver to pry them up, then, using needle nose pliers, pull the rivet out.
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.

Next, remove the intake air duct from your radiator support by lifting it up and out of the intake air housing duct.
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.

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.
If you have hydraulic style tensioners, remove the dust cap (yellow arrow) from the tensioner pulley.
Figure 6

If you have hydraulic style tensioners, remove the dust cap (yellow arrow) from the tensioner pulley.

Once your dust cap is removed, youÃÆ'â€Ã...¡'ll have access to the 8mm Allen nut (red arrow) used to rotate the tensioner.
Figure 7

Once your dust cap is removed, youÂ'll have access to the 8mm Allen nut (red arrow) used to rotate the tensioner.

If you have spring loaded tensioners, use a 16mm hex socket (red arrow) to rotate and release the tension.
Figure 8

If you have spring loaded tensioners, use a 16mm hex socket (red arrow) to rotate and release the tension.

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 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.

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 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.

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

With the belts removed, inspect your 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. See our Pelican Parts Technical Article on Replacing Your Idler Pulley. To install accessory the drive belt, begin by wrapping the belt around the crankshaft pulley, then over and around the power steering pulley, around alternator, around coolant pump and around the tensioner pulley. Avoid running your belt under the idler pulley for now. Once the belt is properly installed on all accessories, release the tensioner as described earlier and slide the belt onto the idler pulley. Tension the belt and check that it is properly aligned and installed in all pulley grooves correctly. Be careful not to force belt onto pulleys because you may damage it. To install the A/C drive belt, begin by wrapping your belt around the crankshaft pulley, then onto the A/C pulley, next bring a loop of the belt toward the tensioner, working through the center of the loop, release the tensioner as described earlier and slide the belt onto the tensioner pulley. Release the tensioner and check that belt is properly aligned and installed on all pulley grooves correctly. Be careful not to force belt onto pulleys because you may damage it. Reinstall the dust caps on the tensioner pulley and install the intake air ducts. Lastly, start your engine and allow it to run for less than 30 seconds, shut engine OFF and recheck belt installation. It helps if you have a friend watch the belt from a safe area as you start the engine.
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Comments and Suggestions:
jay Comments: Hi Nick

I have looked at the article and I have sent pictures of my car because it does not have bolt to de-tension belt. some reason my car don't even have idle pulley. Please have a look at my pictues so you understand.

http://i67.tinypic.com/2mhv7dk.png

http://i66.tinypic.com/ogl920.jpg

it wont let me attached pictures as it is to large. thanks

May 6, 2016
  Followup from the Pelican Staff: Your car uses the same tensioners. I did look at your photos. Minus the idler, it is similar. If you ar having trouble, get a repair manual for your vehicle. - Nick at Pelican Parts  
jay Comments: where is my bolt to remove drive belt. BMW e46 m43 auto 2001.

http://i67.tinypic.com/2mhv7dk.png

http://i66.tinypic.com/ogl920.jpg

May 6, 2016
  Followup from the Pelican Staff: it is the tensioners shown in the article. use the article you commented on to locate them. - Nick at Pelican Parts  
Imedina45 Comments: I went to buy a headlight for my 325i and I was told I need the one with electronic control modual. Do I have to use this particular model or can I use one without it?
January 29, 2016
  Followup from the Pelican Staff: You may have Xenon, then you need the module. Give our parts specialists a call at 1-888-280-7799. They can figure out what part or repair kit you need.
- Nick at Pelican Parts
 
Imedina45 Comments: I have a power steering pump I took off my 03 BMW 325i. Will trade for a headlight driver side.
January 28, 2016
  Followup from the Pelican Staff:
I opened a post in our forums. A Pelican community member may take you up on that. - Nick at Pelican Parts
 
Imedina45 Comments: My mistake was not routing the belt correctly. I took my time trying different positions until I got the right one
Thanks to everyone for their info
January 28, 2016
  Followup from the Pelican Staff: Thanks for the follow up. We appreciate it.
- Nick at Pelican Parts
 
Imedina Comments: 03 BMW 325i. I removed the power steering pump, replaced the high pressure hose. When I tried to reinstall the belt it fit too big. Same belt. Did something move to create a slack? What can I do to install that belt right?
I reinstalled the same pump. Nothing new except the house
January 22, 2016
  Followup from the Pelican Staff: Is the tensioner being moved to the released position? - Nick at Pelican Parts  
Ermi Comments: I was trying to replace drive belt to 04 325i, the belt cams off was very simple however, I can't put the new belt because seems a little short, I pull the tensioner all way down still the belt little short. Then, thought the new belt was wrong, tandem yet trying to put the old one still short. I tried hard to struch the belt never get closer. Now I don't know what to do.? What is the size of belt
July 4, 2015
  Followup from the Pelican Staff: Be sure the belt is engaged in all the pulley grooves and properly routed. If it is, you may have the wrong belt. - Nick at Pelican Parts  
frits Comments: ?
March 24, 2015
  Followup from the Pelican Staff: What can I do for you, Frits? - Nick at Pelican Parts  
ductai696 Comments: I have a 2004 325i beamer and tension pulley went out and I ordered a new one but a slightly different same lengthexcept the original Polly goes to the right and the new one goes to to the left can I use the new pulley
March 20, 2015
  Followup from the Pelican Staff: I would think no. You need the same part number, unless it has been updated. - Nick at Pelican Parts  
drwilmercs Comments: I HAVE A BMW E46 2005 325I MANUAL TRANSMISSION BUT THE DIAGRAM IS DIFERENT FROM WHAT I HAVE ON MY CAR. THE BELT PASSED OVER THE IDLER PULLEy not below as look in the diagram. could be like this or am i wrong?
February 18, 2015
  Followup from the Pelican Staff: The ribs in the belt should not ride on a smooth idler pulley. Is that how yours is? - Nick at Pelican Parts  
Chris Comments: Hi Nick thanks for the quick response.

I have a 2004 BMW 325Ci M54 engine.

Unfortunately I think the picture in Figure 11 is of an older style tensioner. From what I can tell from some reading on forums by people in a similar situation:

On newer cars, the tensioners are apparently all hydraulic past, say, 2000 I think. There is an actual pulley attached at the centre with a T50 torx bolt. immediately above and to the left, there is a 14-16mm hex bolt recessed in a protruding fitting. This fitting looks like it is in the same position as your figure 11, and has an arrow pointing at it in the Bentley manual. Unfortunately this is not the tensioner and a standard bolt so turning clockwise sheared it off at the threads approximately 3 inches along the bolt.

Sadly I don't know if there is much that can be done except drill it out if I'm lucky, but the radiator is in the way... it will be tough.
January 10, 2015
  Followup from the Pelican Staff: Fig 6 and 7 denote the hydraulic tensioner. Do you have this style? - Nick at Pelican Parts  
Chris Comments: Hi, I followed the instructions for loosening the accessory belt tensioner from both your website and the Bentley manual. Turning the tension hex clockwise with a large wrench resulted In increasing the tension and the bolt sheared off.

Do you have any suggestions on how to fix this?
January 10, 2015
  Followup from the Pelican Staff: What vehicle are you working on? - Nick at Pelican Parts  
Paul g. Comments: Hello. I have a question. My mechanical pulley is shot. Should I go to hydraulic as BMW is suggesting, or just get another mechanical one? Which is better? I know the mechanic is cheaper but I'd prefer to do it right.
December 27, 2014
  Followup from the Pelican Staff: What vehicle are you working on? The mechanical tensioner, (assuming that is what you are referring to) has to be set when the belt is installed and does not allow movement or as belt wears. The hydraulic tensioner allows some movement as the belt wears. Overall a better option. - Nick at Pelican Parts  
Devo Comments: Junaid, i bet its your fuel filter bud. I ran into this myself, at exactly 1/4 tank you will run out of fuel thats because your fuel tank is a saddle shape tank which siphons primarily off the deeper end and the shallow end at a 1/4 of a tank. Your fuel filter is probably clogged just enough for it not to be able to pull from the shallow end. Im sure you have fixed this by now but for future if anybody else runs into this make sure to check your fuel filter.
September 5, 2014
  Followup from the Pelican Staff: Thanks for the input on this one. We appreciate the help.
- Nick at Pelican Parts
 
Lem3 Comments: My 2004 330Ci has a T50 Torx in the center of the A/C tensioner pulley. Anyone reading this should have one of those available just in case.
July 15, 2014
  Followup from the Pelican Staff: Thanks for the additional info. We appreciate it.
- Nick at Pelican Parts
 
junaid Comments: Hi Nick check the fuel pressure on the injector rail it was fine could it not be a faulty fuel leveler in the fuel tank and thats why the gauge is reading quarter but in actual fact it might be empty in other way i could be certain.THanks
February 28, 2014
  Followup from the Pelican Staff: It could be running out of fuel, try adding fuel when the problem occurs. See the notes here om how to measure resistance on a fuel lever sender:

http://www.pelicanparts.com/BMW/techarticles/BMW-3-Series-E90/FUEL-Fuel_Pump_Replacement/FUEL-Fuel_Pump_Replacement.htm - Nick at Pelican Parts
 
junaid Comments: hi guys your articles are very helpful my fuel gauge reads quarter but then my bmw e46 325i 2001 just cranks and doesnt want to turn over but as soon as i add fuel it takes immediately is it a faulty gauge or what do you guys think .Thanks
February 28, 2014
  Followup from the Pelican Staff: You could have a bad fuel pump. I would perform a fuel delivery system test. Check fuel pressure, volume and quality.
- Nick at Pelican Parts
 

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