2016 "Cold" Start Rattle, longish road trip in a week.

Hello All,

As a longtime lurker first time poster, I wanted to first say Thank You to everyone who maintains and contributes to these forums. In my younger days, I did general maintenance on my cars, my Gen 1 (currently at 250+ miles with my old neighbor) and some motorcycles but outsourced most of my Gen 3 maintenance to dealers as my job took over my time. I have recently gotten back into DIY in the last few years with the help of these forums given some of the pricing and work quality I was getting and figured I might learn stuff along the way- which I have thanks to all of you.

My 2016 TRD Sport (3.5 V6, Automatic) has 68k miles. All routine maintenance has been done-mostly by dealers. In the last year I did a new pvc valve, spark plugs, the rear diff oil, power steering fluid (all OEM about 1500 miles ago- no known issues from that). Dealers did all scheduled maintenance per the manual prior to that. Oil changes with OEM filters and prop shaft grease about every 5k-7k, engine filter per maintenance schedule. I do not tow, truck has been babied and both the dealer and an independent have told me the truck is “in great shape”. No warning lights, inspected the serpentine belt which hasn’t been replaced yet and will get to it, but no cracking on any teeth and looks to be in good shape. Still get about 22-23 mpg for the driving I do- which is easy.

We are about to go on 1500 mile trip (just changed the oil for it last week- check multiple times no leaks level fine), but I’m a bit concerned given I’ve started to notice a “cold” start rattle for the past month or so (it’s summer here - so it’s just usually the first start of morning or if it’s been sitting for a bit- truck is garaged). I’ve been under the truck on a crawler multiple times now and cannot locate anything loose (was thinking heat shielding)- no loose bolts or anything rattling on the truck front to back and no fluid leaks underneath or under the hood. Nothing under the hood is jumping out at me either as being out of sorts either. The sound seems to be coming towards the back of the engine, probably closer to the driver side but it’s hard to pinpoint. I’ve posted a video (hope it’s playable -first time doing this so apologize) - the sound will be obvious. I can not duplicate this sound going over speed bumps, rough road, or pushing on the truck and it’s only briefly after startup.

https://youtube.com/shorts/5bB3ULnwTyo?feature=share

I’ve done some research on the forums & internet seeing if anything resonates with what I’m hearing. I will continue to search the forums -but given we’re leaving in less than a week I wanted to get this post up. I have read some of the more detailed posts and the one by Sep1911 “Who has cold start rattle? 2016+ 2.7s Potential easy fix” (most of which is way about my pay grade) put me on the VVTi rattle rabbit hole. I watched The Car Care Nut’s video “Toyota VVTi system and why they rattle…”. and while the engines he references that are most common to having this problem are not in the 2016 tacoma and the audio sample he played did not resonate as the sound I’m hearing- what got my attention is when he manually manipulated the VVTi gear with his hands at the 8:50 mark- it is so far the only thing I’ve heard that might approximate what I’m hearing- a quick rattle upon a cold start which lasts a few seconds and goes away- usually immediately but sometimes 20 seconds or so in.

I’ll continue to do my research, but to the degree anyone can identify that noise and how serious it might be given we’ve got a decent road trip coming up in less than a week and whether I should absolutely be thinking about taking our other vehicle or renting one (not my preference) - I would greatly appreciate it. Besides this startup noise, the truck runs perfectly fine, is responsive - all sounds normal and healthy to me when driving/running. Unfortunately I don’t really have a lot of faith in the dealers I have access to right now, so wanted to start here.


Thank you and Happy Labor Day!

 

Are the starter mounting bolts tight? Did noise start before, or after doing the engine oil change?

 

Thank you for the reply.

I’ve checked the flashing around the starter and all the bolts I could get my hand around the starter and it all seems solid. Haven’t done any work from above in 1500 miles and don’t usually keep tools in the bay, but ran magnets over everything and took another good look and found nothing.

I took a video of the a cold start while looking at the starter area from above, what I posted as this second video is cut to me moving from the top to the bottom recognizing it was from below. The sound appears to be coming from somewhere around the transmission, transfer case and catalytic converter. All the flashing around here is solid- I ran magnets both behind and in front of all of heat shielding and other sheet metal to see if I could pick something up and nothing. Nothing is even close to loose on the exhaust either.
Only happens on a cold start.

https://www.youtube.com/watch?v=oY6MCWMxJNQ


I’ve also posted a pic of the area I feel its coming from- I’ve pulled on everything I can get my hands on and ran magnets all over the flashing and sheet metal and can’t come up with anything loose.

Is it possible something is loose inside the catalytic converter that could be vibrating and once it heats up stops (but it stops pretty quickly)? I’m not sure why the transfer case co uld be involved, but both me and my wife have felt that the truck has occasionally moved a bit where were doing this but can’t be 100% - I have a block on the front tire I park against.

I’m at a loss- I’ll take it to the carwash and get an underbody to see if something gets flushed out but at this point a rental is probably what I’m going to do until I can sort it out. Unfortunately I can’t trust the dealers around here so need to find a place if I can’t sort it out.

Thanks again for the reply.

 

The rattling sound seems consitant, does it continue after start up, and how long? Has the starter ever been replaced, and are you the original owner? Hard too tell with camera moving around. If can find a good indy shop, I don’t know about “franchised shops,” maybe they same like Toyota dealers.

 

Thanks, yea I just posted the 2nd video for the audio more than anything so see if anyone had any ideas on if it's something serious. Thanks again for your time!

 

Questions I missed:

Noise has been going on at least a month (so before the last oil change - Mobile 1 and OEM filters from dealer)- just upon first start up of the day usually.
It is consistent- meaning it usually comes on within a few to 15 seconds of a cold startup, lasts at most 10 seconds and won't hear it again. If I shut the truck off and restart it, I don't hear it on the second startup. If I let it sit a few hours- I do. I am the original owner.
Starter was not replaced.

Side note- it will be interesting to see how Rodgers does in Pittsburgh- as a Ravens fan - I look forward to the AFC North battles to come this season! Thanks again for your time.

 

The sound from first video, sounds like starter might be hitting flexplate, flywheel. If you are mechanically inclined, pull starter, and check it out.

If Steelers O-line can protect Aaron Rodgers, give him time, (without penalties), Rodgers has chance, make big plays. It always the case, AFC North battles are "physical!"

 

Kinda does sound like the starter drive is touching the flywheel for a second. Maybe the return spring is weak

 

I agree that sound is starter related or something near it.

 

See if you can position the phone under the truck, pointed at the starter/ flywheel/ converter area and take a video at start-up. You might have to do this on a lift.

Sounds like something contacting an external shield to me.

 

A shot in the dark, but check your skid plate for rocks, AND your cat shields. I had a nasty sound like that and it was pebbles in my cat shield. 2016 113k on it, never had a sound like that and all of a sudden. something to check easily.

 

The catalytic converter can rattle from the inside, I have had some that did it for years with no issues other than the noise.

With the handbrake firmly set and a trusted helper you can be under the truck and have the helper start it up with the engine cold. When the noise starts quickly touch each converter and see if you can feel the noise. Be careful, the converters will heat up quite quickly.

Welcome to the forum also

 

Thanks to everyone for their suggestions (and welcome).

I think the mystery is solved. I took a video as Palomar Taco suggested - was situated between the first and second converter looking up to the starter area. At startup it was immediately clear to me the noise was coming from the left of me almost in front of my face- away from the engine around the 2nd converter. The nuts holding the 2 pieces of cat shield are like putty fused to the shields at this point and the shield seemed very solid, but per Toyota09's suggestion, started poking around under the heat shields with a wire to see if anything was under there and banged/flipped them to see if I could duplicate the sound . Ran my hands along the top shield edges and the top of the bolt on the right side was missing- I’m pretty sure the noise is the 2 pieces of the cat shield coming together at this point.
Sorry (but grateful) it was such a simple issue- thanks again for the comments and suggestions.