I know that there are a lot of threads on this topic but I'd like to provide a couple of solutions that are known to work (Hopefully the mods don't close it)
First I must say that after spending several months chasing this problem, including several trips to my local dealer, I'm amazed, happy and annoyed. Amazed at how simple the solution is, happy that the resonance is gone and annoyed that Toyota haven't fixed this simple problem in 3 years.
Before the solutions, some background. I've been chasing this problem because of some very loud, intermittent and annoying rattles that come and go from the dash area of my car. I also didn't like the drone at 1500rpm. After much stuffing around I couldn't find the rattles so I thought I'd have a crack at the 1500rpm vibration that causes the rattle.
End result, no more 1500rpm drone or vibration and hence no rattles.......touch wood
What causes the drone and vibration at 1500rpm, a resonance in the air intake system. As my local dealer told me this is a issue known by Toyota. What is resonance? Wikipedia says: "In physics, resonance is the tendency of a system to oscillate at a greater amplitude at some frequencies than at others. These are known as the system's resonant frequencies (or resonance frequencies). At these frequencies, even small periodic driving forces can produce large amplitude oscillations, because the system stores vibrational energy". In other words resonance amplifies a small input into a large output. It occurs in all kinds of ways and has even been known to cause airplanes to crash.
In the Prado the resonance occurs in the air intake chamber, which happens to be the area inside the right hand front guard. Resonance can be fixed by changing the properties of the space, such as changing the shape, volume or materials.
So what are the solutions to the Prado 1500rpm drone, resonance and vibration?
A. Fit a snorkel, this changes the size of the chamber and changes the resonant frequency. Unfortunately for me because of a decree by "the ministry of war", a snorkel is not an option.
B. Change the characteristics of the air intake chamber. There are probably lots of ways to do this, I did it using some high density acoustic foam, some Dynamat ($40) and 10 plastic retaining clips (Toyota $1.80 each). The job took me about 90 minutes, mainly because the non-reusable plastic clips that hold the plastic mudguard liner in place are not easy to get out. Make sure you buy 10 replacement clips. And yes I think Toyota should pay to do this, but anyway.
Step 1: remove the plastic mudguard liner, 10 clips and about 4 screws
Step 2: install the Dynamat to the inside of the guard. Below is a photo looking up into the guard before sticking on the Dynamat
Dynamat is self-adhesive; I stuck it on and then cut it to suit. I covered the whole inside of the guard. (The brown paper is the backing that you peel off to stick the Dynamat to the guard, it is very sticky!)
Step 3: the photo isn't very clear, but I jammed a piece of high density foam under the guard where it meets the A pillar. You can reach this from inside the guard to push it up, with the plastic mudguard liner removed. This is where Toyota cut the plastic tab and move the fender slightly away from the body.
Step 4: stick left over Dynamat in the cavity and onto the back of the plastic mudguard liner.
Step 5: I jammed some pieces of the acoustic foam into various spots under the guard and glued a piece to the top of the plastic mudguard liner.
So now the 1500rpm drone is unnoticeable, the vibration is nearly gone, and the rattle is pretty well gone, hopefully for good this time. More annoying is that my car wouldn't have developed the rattle if Toyota had fixed the resonance in the first place.
Hope this helps others struggling with this problem.
First I must say that after spending several months chasing this problem, including several trips to my local dealer, I'm amazed, happy and annoyed. Amazed at how simple the solution is, happy that the resonance is gone and annoyed that Toyota haven't fixed this simple problem in 3 years.
Before the solutions, some background. I've been chasing this problem because of some very loud, intermittent and annoying rattles that come and go from the dash area of my car. I also didn't like the drone at 1500rpm. After much stuffing around I couldn't find the rattles so I thought I'd have a crack at the 1500rpm vibration that causes the rattle.
End result, no more 1500rpm drone or vibration and hence no rattles.......touch wood
What causes the drone and vibration at 1500rpm, a resonance in the air intake system. As my local dealer told me this is a issue known by Toyota. What is resonance? Wikipedia says: "In physics, resonance is the tendency of a system to oscillate at a greater amplitude at some frequencies than at others. These are known as the system's resonant frequencies (or resonance frequencies). At these frequencies, even small periodic driving forces can produce large amplitude oscillations, because the system stores vibrational energy". In other words resonance amplifies a small input into a large output. It occurs in all kinds of ways and has even been known to cause airplanes to crash.
In the Prado the resonance occurs in the air intake chamber, which happens to be the area inside the right hand front guard. Resonance can be fixed by changing the properties of the space, such as changing the shape, volume or materials.
So what are the solutions to the Prado 1500rpm drone, resonance and vibration?
A. Fit a snorkel, this changes the size of the chamber and changes the resonant frequency. Unfortunately for me because of a decree by "the ministry of war", a snorkel is not an option.
B. Change the characteristics of the air intake chamber. There are probably lots of ways to do this, I did it using some high density acoustic foam, some Dynamat ($40) and 10 plastic retaining clips (Toyota $1.80 each). The job took me about 90 minutes, mainly because the non-reusable plastic clips that hold the plastic mudguard liner in place are not easy to get out. Make sure you buy 10 replacement clips. And yes I think Toyota should pay to do this, but anyway.
Step 1: remove the plastic mudguard liner, 10 clips and about 4 screws
Step 2: install the Dynamat to the inside of the guard. Below is a photo looking up into the guard before sticking on the Dynamat
Dynamat is self-adhesive; I stuck it on and then cut it to suit. I covered the whole inside of the guard. (The brown paper is the backing that you peel off to stick the Dynamat to the guard, it is very sticky!)
Step 3: the photo isn't very clear, but I jammed a piece of high density foam under the guard where it meets the A pillar. You can reach this from inside the guard to push it up, with the plastic mudguard liner removed. This is where Toyota cut the plastic tab and move the fender slightly away from the body.
Step 4: stick left over Dynamat in the cavity and onto the back of the plastic mudguard liner.
Step 5: I jammed some pieces of the acoustic foam into various spots under the guard and glued a piece to the top of the plastic mudguard liner.
So now the 1500rpm drone is unnoticeable, the vibration is nearly gone, and the rattle is pretty well gone, hopefully for good this time. More annoying is that my car wouldn't have developed the rattle if Toyota had fixed the resonance in the first place.
Hope this helps others struggling with this problem.
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