3.4 Tacoma engine rattle at 3,000rpms

https://youtu.be/RUBxV3BB7vo
another angle just don’t see anything rattling ?

 

that is too light of a rattle to be an internal to the engine. If possible smack the cat when it rattles to see if the tone changes.

 

... have a 2-3 foot long piece of broomstick handy ? Put one end on and "near" noise and other end to ear ... careful near spinning objects ... think poor man stethoscope ... I have used this to pinpoint bearings going bad. Don't stick opposite end directly on ear, cup your hand like a megaphone, put ear on that, then to handle.

 

SOLVED: dust cover or inspection cover on back of tranny was missing a bolt. Fuckers forgot to put the bolts back after doing clutch.

 

weird!
i have not done a clutch job at all on mine
guess it could be that U shaped shield, the bolts looked tight on last i checked
will check them again

 

I will try and get photos

 

Ah man, these guys nailed it. I had my doubts on a shield or cover or something, granted my hearing is poor. These guys are good man. And good on you for finding it and actually putting forth effort and getting it done dude

 

There is a heat shield on the crossover pipe on the back of the engine.

 

would that only vibrate some of the time or all of the time?

 

Don't know. I haven't had one vibrate yet.

 

Certain things will only vibrate at certain frequencies. It's called resonate frequency. Heat shields and thin metal are known for only making noise when a certain amount of vibration is present.

 

so now the mystery boils down to what is resonating at 2.1k RPMs for my situation.

 

https://youtu.be/G8xp-luncWQ
watch video ...

 

You can start tapping on things with a wrench to see what sounds like the noise

 

not when i am going 30 to 50+ mph i cannot stick my head underneath lol
this rattle has not yet been induced in neutral, at least not as noticeable yet
i had the glovebox out for a couple months because it sounded like it was coming from behind there but did not find it

 

Has to be a heat shield. Exhaust, cat, behind engine shields ? Really really really get your ears and eyes and hands on everything. Have someone rev engine while you crawl all around. I spent weeks trying to find a rattle and finally dedicated a couple hours and figured it out.

 

the A/C in operation makes it MUCH worse from last summer which i have no clue and the Toyota expert mechanics have no clue when I explained what happens when it happens

but maybe it will not come back this spring/summer

as soon as i mentioned the A/C the service dept quoted me about $150 to check the A/C
but the A/C is working just fine

 

Can you post videos please ?

 

AC increases the load on the engine and in turn the vibrations it produces. It can also raise the idle so maybe try to be very gentle with the throttle in neutral and just barely bring it off idle. Sometimes things have to be in a certain position to rattle as well. Once you put it in gear, the engine will keep pressure on one side due to the resistance of the drivetrain. Like my cat heat shield likes to hit my skid when I'm pulling hard. Another thing I'd check out is your motor mounts. Maybe they're worn out and allowing the engine to roll into a position it shouldnt be in. What's the noise sound like and wheres it coming from?

If it sounds like a dash rattle, a lot of people (myself included) have found the ducting for the HVAC to be rattling due to the degradation of the foam that goes between the male and female ends

 

parked truck in garage
revved motor in neutral to approximate RPMs (2.1k) where last summers insane vibe was occurring (checking if it was a loose heat shield under there and the garage effect would induce an echo for possible assurance)

NO RATTLE, Nothing
wot'n tarnation!!


does this rule out ALL heat shields?
i had the RPM up nearly to 3k too and nothing no vibes nothing

how do you diagnose something when it only happens haphazardly and ON THE MOVE