Odd Noise After Turning Truck Off

Long time listener, first time caller here.

1996 V6 Tacoma LX 4WD. 191,XXX on the odometer. New to me as of about 5,000 miles ago.

It has this odd sort of cyclical sound after shutting the motor off. Almost like the soft song of a frog living under the hood.

Attaching some video. First one gives good representation of the sound from under the driver front wheel well. Second sounds a bit raspier than the actual sound, but wanted to film the engine compartment to locate the noise. Seems to be coming from driver’s side back toward the firewall.

Any ideas?





Forgive me if this has already been answered. Seems the newer gen Tacos has a noisy smog pump. Not sure if this is the same thing as I couldn’t find a video example.

 

how long does it last after turning engine off?
i have not noticed any sound of this sorts on mine yet
i do have other abnormal sounds however

 

Honestly, I’m usually on the move and haven’t stuck around long enough to actually time it!

I’d say at least 5-10 minutes. That’s about how long it takes me to rig up my fly fishing junk and head to the river.

 

You, sir, have a haunted truck and need an exorcist

I've never heard that before so I have no idea what it is, but my 04 has never made a noise like that after shutting off.

In the second video it seems to get a lot louder when you're right over the brake booster/master cylinder...but I know that's not much of an explanation.

 

You sure it's not coming from the evap canister? Mine makes noise after shutting off the engine but sounds different than that. Could be just the way the mic is picking up the sound though.

 

Well well...that's bizarre. brake booster?? Never heard anything like that before.
Jeff

 

do you think those vacuum hoses need new replacements, 23yrs old they are probably getting to the point
but I would think the CEL light would come on with a leaky hose?

 

Geez, the PO conveniently left that part out of the Craigslist ad...

 

Never thrown a code or had a light pop on in my short tenure as owner, but yes, the lines could probably use a freshening up nevertheless. This might need a trip to the local Toyota Only shop for a proper diagnosis.

 

Keep us posted. Very curious about this.
Jeff

 

Was really hoping for a "That happens to em all, don't worry about it!" kind of response from everyone. D'oh!

I'm going to go ahead and make an appointment with my Yota dudes and will keep everyone posted.

 

there is still time for TW diagnosis, not everybody that has as old of a truck has probably seen this topic yet!

 

If it makes you feel any better, my truck makes all kinds of noises that make me uneasy as well. Just nothing like that after I shut it off

 

You got it for the win!

Just off the phone with Master Technician Toyota Only here in Missoula (great shop). He said that he's 99% sure that it's the EVAP canister purging, which is totally normal. Also said that it was likely to happen on hotter days (was 95 F yesterday when I took the video).

Funny, he was able to mimic the sound right as soon as I mentioned the frog that lives under the hood. Always love it when a call to the shop results in "that's nothing don't sweat it" or "that's an easy fix you could probably handle on your own."

I should have called my guys first, but then again it never hurts to have some public knowledge and an example out there for others.

 

they 'dealer' diagnosed my coolant leak as the top radiator hose yesterday
and it will cost me $280 for them to fix the hose... beware of that going into the expert dealer


the evap canister should be a simple DIY fix?

 

I wonder if it's an earlier 1st gen Tacoma thing? I've never heard my evap canister make a noise and I live in (near) the desert. Maybe it becomes more pronounced at higher mileage. Anyway, good to know you got it solved without needing to call in a priest

 

is your canister even in the engine compartment?
and your mileage is still under 100k?

 

@beignet
Sounds like the evap canister "check valve flutter".
Inertia of the air in one of the lines would cause a valve in the canister to flutter or click rhythmically.
Toyota came up with a fix that consisted of a small plastic box glued on the canister to serve as a plenum to deaden the air pulses and quiet the sound. Later years incorporated this "box" from the factory. It's really no more than a little plastic box if you want to try it yourself. FWIW the noise is harmless.

The later factory canister with the "box" seen here with the front hose coming off it. There is very little pressure involved if you want to improvise something. Seen under the start of the arrow.

 

My 02 DC Pre Runner Supercharged 4cyl with 72k original miles makes that sound . The sound comes from the gas tank / gas cap area

 

Pretty sure mine is near the gas tank

I have 83k miles on my truck...never once heard that noise but I guess some are just louder than others.