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2009 Highlander Limited 3.5, every factory option
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Discussion Starter #1
I‘m creating a separate thread for my knocking noise and obviously hoping it’s not a rod knock which it sure sounds like. I’m trying to wrap up another project and then I can change the rear plugs and rule those out. I also have at least one small exhaust leak but that’s minor.

I haven’t done any troubleshooting yet. Oil level is good (unknown type viscosity) but changed within the past 1,500 miles by prior owner. It looks good and not down at all. No oil light flickering or anything like that, no dash lights on at all. Engine starts, idles and runs great other than this noise.

I wanted to get an initial impression and will follow up once I dig in a little deeper. Isn’t an internal engine issue almost unheard on a 3.5 unless really abused?




thanks
Bob
 

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Hard to tell from the video. Is the noise present all the time, cold and operating temp? What about when driving? Motor mount(s)? Hope it's an easy fix like a loose exhaust hanger or something like that.
 

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2009 Highlander Limited 3.5, every factory option
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Discussion Starter #3
It has mysteriously stopped on a couple of occasions, no idea why. Aside from that, no perceptible change hot vs cold. I LOVE the idea of a bad mount, I had both side Mounts and the dogbone removed for the suspension work. I only hear it on acceleration but it could be doing it all the time. If I’m on a slight incline and just barely hit the throttle, it’s probably the loudest which I was trying to replicate in the video.

I’ll post back, thanks
 

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I hate when noises mysteriously go away like that. Maybe you could send YouTube mechanic Scotty Kilmer the question on what he thinks of the noise in your video?
 

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Definitely sounds like a bottom end knock.....once per crankshaft revolution. I would get out a stethoscope or wood broom handle and locate it ASAP. If it is a rod journal, it will quickly destroy the motor. If that checks out OK I would rule out a cracked flex-plate between the torque converter and engine crankshaft. They sound similar to a knock. Hope that helps.
 

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To me it sounds like something exhaust related. Something down there rattling at the right frequency.
 

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2009 Highlander Limited 3.5, every factory option
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48 Posts
Discussion Starter #7 (Edited)
Update, I narrowed down where the noise if coming from and it sounds like timing chain area. This is in drive, brake on with light throttle to force the noise and hold it there. I don't have the VVTi startup noise when cold, seems like I might have the opposite problem. Wondering if it's sludge build up and oil not flowing great to the top end of the valve train.

After the video stopped, as idle was coming down it also sounded like it was coming from inside the intake manifold. Someone posted about broken baffles being a common issue on the Camry but I haven't seen this from any HL owners. When I let off the gas at normal idle it sounds great. It might only do this for a few seconds as I'm throttling up and then stops. I'm "holding" the noise here but it might not be continuous. I just don't know. Might be a good time to get an oil pressure gauge on it and see what that's reading.

What do you think? Yeah, I'll send the link to Scotty Kilmer.


 

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2009 Highlander Limited 3.5, every factory option
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Discussion Starter #9
Should be good for the life of the engine, I haven’t heard of anyone replacing one.
 
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