3MZ-FE noise

[paulri]

the engine in my Highlander occasionally makes this sound, usually for a few seconds when I'm accelerating up a slope. I heard it a lot running errands this morning, but on my second (last) trip I kept the windows open, ac off and didn't hear it at all.

https://www.youtube.com/watch?v=rU_7Pe-eAzc

Not my video or vehicle, but the sound is just like this. It sounds quite a lot like the sound a diesel engine makes but of course not nearly as loud.

Anyways, is this something that a higher octane gas can address? I have also heard that this isn't a problem if you have knock sensors. I guess my first question should be, is this anything I need to be worried about?

 

[supton]

That it comes and goes under load makes me think engine mount or cracked manifold. The engine moves under load, and something starts tapping away, or the manifold crack opens up and you can then hear the exhaust.

 

[bbhero]

I bet you are right about this... Motor mount or manifold leak.

 

[kschachn]

That sounds like my Accord when it had a broken flex plate between the transmission and the engine.

 

[ARCOgraphite]

Originally Posted by paulri
the engine in my Highlander occasionally makes this sound, usually for a few seconds when I'm accelerating up a slope. I heard it a lot running errands this morning, but on my second (last) trip I kept the windows open, ac off and didn't hear it at all.

https://www.youtube.com/watch?v=rU_7Pe-eAzc

Not my video or vehicle, but the sound is just like this. It sounds quite a lot like the sound a diesel engine makes but of course not nearly as loud.

Anyways, is this something that a higher octane gas can address? I have also heard that this isn't a problem if you have knock sensors. I guess my first question should be, is this anything I need to be worried about?

I think you are hearing pinging. given the conditions under which it occurs.

I drive pretty hard and I cant drive hard enough to keep an engine clean these days.

- You can put the trans in a lower gear when going up hill

- You can try mixing in say 3 gallons of premium 91 or 93 when you put in your regular.

Don't run premium straight that's overkill.


IDK the noise in the video its not at a valve opening frequency at idle.

It could be a flex plate, (as kschachn noted above) with a small crack. given the frequency of the noise.

 

[UncleDave]

sounds like a cracked manifold...

Take a lit stick of incense and while is smoking pass it in from of the exhaust manifolds close to the heads and watch for pressure pulses

UD

 

[wag123]

Originally Posted by UncleDave
sounds like a cracked manifold

+3
It could also have a broken exhaust manifold mounting bolt (or bolts). I had this problem (and exact same noise) on my 1995 Nissan Quest, broken bolts were common on the 3.0L V6 from that era. Many later model Ram pickups with the 5.7L also have this problem.

 

[JMJNet]

Have you posted this at ToyotaNation? or other Toyota forums?

 

[paulri]

No, I have a TN login, but I rarely use it as there are more toyota users that post here than there. I get maybe 1-3 replies per week there, versus well you can see how many in just a few hours here.

Originally Posted by JMJNet
Have you posted this at ToyotaNation? or other Toyota forums?

 

[paulri]

OK I'll see if it is a manifold leak first. It is cheaper to do that than fill up with 91 or 89 octane. I'll report back when I have an answer.

 

[14Accent]

To me, that doesn't sound like an exhaust leak or pinging. That video is textbook valve train noise, and that's not what you're describing.

I'm leaning towards detonation, being as it occurs at low speeds and under acceleration. I've never noticed detonation on a hybrid Highlander, but carbon buildup can do weird things.

I would start by filling up with a tank of premium and a bottle of Techron, and get the engine running hard. It's counter-intuitive with a hybrid, but don't be afraid to give her the business.

 

[Ded Mazai]

Sounds like a stuck valve lifter.

 

[ARCOgraphite]

Wrong frequency. Forget the video that not his car.