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Squealing from engine bay - coasting and under load (intermittent)

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  • #46
    No I didn't try putting it in neutral, didn't think there was any point. Squeal already stopped at times just lighten the foot of the accelerator and coasting, so yes it can be load sensitive. But suspension work affected it too. Hence thought it was a loose bearing changing the orientation of brake rotor to caliper, but load related micro movements with healthy bearings may already be enough. Couldn't really force it to come on, it would just start at some stage during a drive, for short moments initially, then get more constant as drive continued. But I had it also squealing right down to a stop and pitch did not change, that is what it makes me think its resonance, pitch purely determined by the mass of the vibrating body. It did do it also when towing a caravan of 2.3t, symptoms exactly the same, but caravan brake controller is inertia sensing and brake rate is adjusted to match that of the Prado. Very hard to locate by listening, comes sort off from everywhere, sound probably reflected and bounced around off the road, and may be not just one brake doing it, assuming that is the actual cause. Hence also not being able to demo it to anyone, more or less guessing and checking possible causes one after another. Depends really when your squeals started, mine in both cases with pads around half worn. I do a lot of suburbia driving during the week, mostly prefer driving in S so and pushing down on stops, so half worn is roughly at 40000km. If one did a lot highway cruising it would take longer and also would be longer to get through the squealy period due to reduced brake wear. A trailer of your stated weight would be braked and hence with brakes adjusted with matching brake rate to Prado would hence not affect brake wear rate.


    • #47
      Originally posted by Greasemonkey View Post
      I'm now speculating that it is perhaps a resonance situation with half worn brake pads, just having the right mass at that wear level. Now that they are light in my case they perhaps don't resonate anymore, just like is the case when they are too heavy when new, just off tune. I haven't got an opportunity to check third time round for a while as a will wear those pads out till they actually need replacing. My experience might not apply to your situation but may be worth a thought, check and discussion.
      Hmmm. I might just look into this a bit more. Once I had the suspension lifted it, the noise went away for months but this might be another avenue to look at ...Thanks


      • #48
        Quite interesting reading this. Iíve got a 2013 D4D (non dpf) making a similar noise for 2 years now and weíve narrowed it down and isolated it to an exhaust coupling under the drivers seat area. Itís a weird coupling with two spring and bolts, same as been posted up here already.

        Typically, Toyota view the exhaust as wear and tear so not covered under warranty.

        The cost of the replacement coupling is $150 less than a complete new stainless steel exhaust which Iíll be fitting in a month or so. Will see if that fixes the issue.
        2013 150 Prado Altitude D4D in Graphite - [B][URL=""]My Rig Build thread[/URL][/B]


        • #49
          Originally posted by Brougham View Post
          Quite interesting reading this. Iíve got a 2013 D4D (non dpf) making a similar noise for 2 years now and weíve narrowed it down
          I hadn't been on Pradopoint for a while. I wonder how you went with this?