Monthly Archives: July 2021

Rattling Engine Noises from 2003 Acura MDX

My friend gets a 2003 Acura MDX, and recently he hears noises coming from the driving belt, we suspect it is the problem with the driving belt and I think it could be tensioner pulley

Here is the driving belt diagram:

Knowledge preparation from a good source

My friend like Eric’s video, which is also a good resource for auto repair.

As the above diagram shows, a serpentine belt slithers over several pulleys whose rotational energy powers different devices. The belt is typically connected to the following accessories:

The belt helps power the alternator, which keeps your battery charged.

Power Steering Pump
The power steering pump pressurizes the hydraulic steering fluid. Without the belt running the pump, the driver could experience a sudden loss of power steering, which makes handling much tougher.

Air Conditioning Compressor
An air conditioning compressor sends fluid throughout the air conditioning system, so its functionality is key to keeping cool.

Water Pump
An engine needs the water pump to push coolant through the system and keep its temperature down. If the belt fails, it could result in your car overheating.

Water pump is driven by the timing belt that is connected to the driving shelf.

There is a video of replacing the timing belt, it shows the details belt/pulley connection.

I have found the closest video is from the second generation MDX. It is good enough for me to start from somewhere.

The lower 12 mm bolt: 22 newton-meter, 16 lb/ft
The 14 on the tensioner: 44 newton-meter, 32 lb/ft
The pulley only torque is: 59 lb/ft

Step by step protocol

  • Prepare and line up the tools
  • Sketch the belt diagram
  • Loosen the tensioner and release the belt
  • Remove the 14 mm bolt and 12 mm bolt to remove the tensioner
  • Install the new tensioner: 16 lb/ft for the 12 mm bolt and 32 lb/ft for the 14 mm bolt
  • Install the new belt to wrap all the component, by loosing the tensioner to finish
  • Unfortunately, replacing the belt and tensioner does NOT solve the problem. From Scotty’s video, he explains that it could be other pulleys. Well, we have water pump or alternator etc. He has another video that further explain how to use the right tool for the right job.

    Another guy has summarized eight different kinds of noises. We will see how we can get to the bottom of it.

    I have to study more and I am accumulating more videos at this point and after further examination, it starts to points to the crankshaft or harmonic balancer.

  • This is the first video
  • Okay, after all these "research", I think I eventually find a guy that shows exactly the the problem of harmonic balancer and how to fix it. I think this is a good video for fixing balancer wobbling.
  • This video explains very well on what can go wrong if the harmonic balancer goes bad.
  • Someone posted replacing the timing belt that needs to remove harmonic balancer as a start.
  • The same guy posted the installation video as well.
  • To clarify, the crankshaft pulley is different from the harmonic balancer.
  • To get the job done, we would need a crank pulley tool and a puller
  • After all these effort, I come to this diagnosis. The wobbling noise comes from the AC clutch pulley. here are some good videos fixing the clutch.

    I noticed the wobble when I wiggle the wheel bearing, so, I think it could be it. I found a very good video, and hopefully we can fix it somehow. 
    This guy shows a good video tutorial.
    Another guy is doing the same in vitro video.
    This one is for 2003 MDX specifically.
    There could be challenges removing the plat or the pulley, spacer is also critical for the AC to work.
    This guy explains in more details on how to get the plat off and measure the space between the plat and the pulley.
    The guys shows the important to check gap between the plate and clutch pulley.

    To replace the clutch pulley seems quite simple and intuitive, but I encountered resistant from step 1. The following are the steps I need to achieve one by one

  • Remove the 10 mm bolt on the clutch plate. Luckily, done
  • Remove the clutch plate, but I can't!

  • Can I use these tools to remove it?
  • Remove the clutch pulley, by removing the clip ring, then hammering it out.
  • Mount the clutch pulley back
  • Mount the clutch plate
  • Adjust the gap between the plat and clutch pulley
  • Going through all these research, I want to document something related to the car AC system.

    This video demonstrates how to diagnose a bad compressor.

    Parts and tools for this project

    Here is the serpentine belt assembly kit that I have replaced and it does not help to solve the problem.
    Here is the compressor that fits 2003-2006 Acura MDX
    Here is the compressor clutch and pulley that fits 2003-2006 Acura MDX

    Okay, it seems that we may have to be prepared to replace the compressor!

    Main steps are here as shown in the video:

  • Remove the serpentine belt
  • Remove the coolant fans to get room
  • Discharge all the freon
  • Disconnect the high/low pressor connection
  • Remove top two bolts from the top, two bolts from the bottom
  • Unplug the connection socket
  • Remove the metal bar to get more room
  • Remove the old ac compressor
  • Reverse the above steps and make sure all the connection are secured, reinstall the belt
  • Be sure to use the new o-rings for pipe connections.
  • Re-charge the freon
  • To work with the pressor, here is a good video on this.