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BMW & MINI Serpentine Belt & Pulley Replacement – DIY Video

August 2, 2010

We recommend replacement of the serpentine accessory drive belts and tensioner/idler pulleys at 60,000 mile or 4-year intervals.  Replacement is very easy and straight forward.  In this video, we’ll show you the procedure on a 2001 3.0 Z3.  Other six cylinder models are similar, as are the V8s and MINIs.  The applicable Bentley repair manual will address the specific details for your BMW or Mini model.

Click below for Bentley Repair Manuals:

In the video, we use a few special tools, to include the Fan Clutch Wrench, Pulley Holder Tool and Non-Marring Pry Tools.

Click below for Fan Clutch & Pulley Holder Tools:

Click below for Non-Marring Pry Tools:

18 Comments
  1. z4er permalink

    Excellent video, thank you!
    How is this procedure performed on a z4? There is this frame thing between the radiator fan and the engine and it doesn’t look like it’s something one should or could easily remove. The right-side belt looks like it may be somewhat accessible if the air filter box is removed but the other one seems to only be accessible from underneath, which is a lot less feasible in a DIY scenario.

    Is there any way to do this on a z4, other than working from underneath?

    • Your Z4 does not have the engine driven radiator cooling fan, as shown in the video. The Z4 (as well as other late-model BMWs) uses only an electric cooling fan. The fan unit is mounted to the rear side of the radiator (between the radiator and the engine). The complete unit is removed in a similar way to the fan shroud, in the video.

      We show the removal of the electric fan unit, in the DIY article for replacing a water pump, in the Spring 2007 issue of our Fast Times newsletter (Page-6, figure-6). This is done on a 2001 330i, but your Z4 would be similar.

      Click HERE for the Spring 2007 Fast Times

      Once the fan unit is removed, you should be able to replace both belts from above. Your clearance will be a bit tighter than what you see in the video, since your radiator will still be in-place.

  2. Follow-up for those interested in doing this on the z4:
    I managed to pull out the fan assembly. Once the cover is removed (held by 2 torx screws and 8 of those plastic screws/anchors), the radiator and fan assembly are revealed. The fan assembly is held in place by only one plastic rivet (right side) and one screw (left side). Once these two plus two electric connectors are removed, the fan assembly slides right out (easier than in the video).
    From there on it all works as in the video above. The frame I was concerned about (visible in the picture) does get in the way but it still leaves enough room. The filter box does not need to be removed.

  3. Gary permalink

    Otto, I have a 2002 330i and plan on replacing the serp and AC belts along with the tensioners (should I do the water pump and thermostat as well (75,000 miles)?

    Also, what type of tensioner does the vehicle have, hydraulic or spring?
    Thanks!

    • Unfortunately, your 330i could have either the mechanical or the hydraulic tensioner system for the main belt. The BMW micro-film lists both systems for your application …. and we have seen both systems on the 3-liter models. You will need to take a look at it first. With this point made, we would say that the hydraulic unit is more common on the 2002 and later models. The A/C belt does have a mechanical tensioner.

      At 75,000 miles, you may indeed wish to replace the water pump and the thermostat as a preventative maintenance action, to assure that you won’t be sitting on the side of the road (at best) with a damaged engine (at worst) due to a failed water pump bearing. If you find no play in the pump’s shaft, it is up to you as to whether you just wish to take care of it while it is “right there” during the belt work, or to let it go for replacement at a future time.

  4. Orlando Cordero permalink

    Excellent video! Thanks for all the help provided.

    It may help other 2001 530i owners to know that I was able to replace my belts (not the tensioners) without removing the air filter housing, fan and shroud. I raised the front of the car on ramps. Then working from under the car, I removed the plastic cover under the engine (name?) and used a ratchet with a long handle or extender to access the upper tensioner bolt. The lower tensioner can be accessed with any wrench. I found it to be easier and faster and did not need the special tools to remove the fan.

    • Thank you for your input. And, yes, most models can be done in this manner, as well as accessing from above.

  5. lcc014 permalink

    My 2005 530i (M54) engine does not need to remove the fan to undo the AC belt and alternator belt. Fan is on the radiator side. However, it would be easier to replace these belts if the fan shroud is taken off from radiator. Both belts have belt tensioner which are needed to be unloose the belt tension before taking the belts off.

    • Various E46 (3-series 99-05), E39 (5-series 97-03) models, and others, do not have an engine mounted fan (from the water pump). These models have an electric fan that is integral with the shroud assembly.

  6. rob permalink

    Otto – I have an 94 E34 M50 with a hydraulic belt tensioner. To replace the pulley, do I simply turn the 8MM hex bolt (in the center of the pulley) counter clockwise? Or do I need to remove the entire tensioner assembly?

  7. Sam permalink

    Otto – I have a 2006 E65 (750i) and wanted to know if both belts could be replaced from the bottom of the car w/o removing the fan and shroud?

    • I would say that the answer to this would be “no”. You cannot get to all of the belt contact points from below.

  8. Mike permalink

    Otto,
    Does the 2005 745LI, A/C belt have a tensioner on it that like the T60 on the main system belt?

    • The newer N62 V8 engines used in the E60/E61 (5-series 04-10), E65/E66 (7-series 01-08), E70 (X5 07-current), E71 (X6 current) chassis have female Torx (T60) adjuster provisions on the mechanical tensioners. Both the main belt tensioner and the A/C belt tensioner have this provision.

      In these cases, use a male Torx bit (T60) and a ratchet or breaker bar to detension the tensioner and remove the belt.

      BMW N62 V8 belt tensioner Torx T60

  9. John permalink

    Otto,
    On my 97 318i E36 the belt tensioner pulley is attached with a torx head bolt. I wanted to change the pulley along with my belts. I was unable to remove the bolt as the torx head started to strip. Do I turn the torx head clock wise rather than counter clock wise to loosen it? Also can I purchase a hex head bolt to replace the torx head bolt.

  10. Michael permalink

    Otto:

    Is it necessary to replace the tension pulleys to the serpentine and AC belts when changing belts?

    • We do recommend replacing the pulleys when replacing the belts. This assures that you will not be subject to possible pulley failure at some point after the belt replacement, which would destroy the belts and possibly cause additional damage.

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