2016 Tundra Strange Knock in Engine Compartment After Startup

I had something similar on a Dodge Dakota (4.7L) I used to own. Turned out to be the head gasket. As it was explained to me... exhaust was leaking through the gasket until the engine warmed up. After the engine was warm, the gasket would expand with heat to seal the leak temporarily. Gasket was replaced, noise went away, truck was traded shortly after.

 

LOL

 

Here’s ours. Been happening off and on for about a year and a half maybe? I first noticed it on a significantly colder morning than usual at T2S 2018, so April 2018.

it became more prominent when we moved to Ohio last winter and had much colder morning temps than in Phoenix.

Sounds like lifter noise to me, but I’m open to speculation. Truck will be going to the dealer next week most likely. I’m traveling for work this week.

https://youtu.be/2eGs9Aw1Ucw

 

also notice how it will suddenly stop making the noise and start again. It’s also different sound from the passenger and driver sides.

 

Sounds do weird things within a space. To me it sounds like probably the same source, something more drivers side than passenger, and the sound difference on the passenger side may be due to reverberation within the space. I’m sorry I haven’t a clue what the cause is, but maybe the guys who’ve chimed in already will do again. I sure hope an answer surfaces or that the few ideas on this thread narrow it down when you take it the dealer.

 

I mentioned earlier my 02 chevy 4.8 had the same knocking sound when cold. I had done research at the time and there was tons of info about it. There was TSB’s regarding the issue and it seemed to be a very normal thing and not to worry. TSB’s cited piston and cylinder wall interaction. https://www.silveradosierra.com/vortec-5-3l-v8/knocking-noise-when-cold-t18979.html

My 2013 does the knocking thing from time to time, 60k miles with a Supercharger. Dont think Im going to worry about it despite it sounding kinda concerning.

 

Agree with @Sunnier, noise source is on the driver side, and maybe "telegraphing" to the passenger side. Sounds like valve noise to me. As for it coming and going, it's hard to judge that from a video because if the camera is turned just slightly, the audio seems to go away. Coming and going would also indicate valve noise in my opinion; e.g. lifter rotates slightly in the bore, and it could be a whole new set of conditions for 20-30 seconds.

Use a stethoscope and see if you can isolate a location. I doubt the dealer guys will be able to help you (give it a try)...unless...you want to spend a lot of money ($$$$). Again, I would experiment with different brands and grades of motor oil...I know it's a tired mantra, but the alternative could be very expensive and may not last a year. In the long run, the presence or absence of that noise will have very little impact on engine longevity in my opinion. It's a Toyota...quit worryin'.

How many miles? Good maintenance history?

 

I cant tell for sure by listening to it on my phone, but on my old 08 I narrowed a noise just like that down to the vvti cam gears. It would happen after 3k on the oil and if it sat for longer than 6 hours and was below 40F.

I was finally able to get it to go away by redlining it for a sec on my way home where it was going to sit all night.

There are other toyota motors that have this same issue which how I found out about the redline(using vvti) trick. My scion had the vvti gears replaced on warranty for this same issue, but it had been doing it at any temp after sitting for 3 hours.

 

I like the sentiment that led to that discovery..."If I can't figure out how to fix this bastich, then I'll beat TELH out of it until it finally breaks for real!"

 

Mine is making the same intermittent sounds on cold idle. I also get a metallic thrap, thrap, thrap, on start up right after an oil change. My guess was timing chain tensioner failing.

Let me know what you find out. I’ve struggled to get much traction with local mechanic due to being difficult to replicate.

 

Yeah I agree, I don't think there are two different noises, I think it's one noise that just sounds differently from side to side due to sound propagation through the engine and bay.I'll grab a stethoscope and try to isolate it. I used to do that years ago, but don't have any of my tools with me here since I don't have a garage to work on the truck in.

We have a good relationship with our dealer and factory extended warranty, so I'll bring it to them next week. I just want to be able let them know what I've seen or heard so far.

85k miles and religious maintenance record. We drive the truck hard, so we treat it well with fluid and filter changes regularly. We probably have 7 trips back and forth across the country non-stop where Lisa and I take turns driving, for 36-48 hours, only stopping for gas (constantly, LoL) and food/potty breaks. Plus all the abuse we put it through off road. We definitely buy Toyota for a reason.

Our only break/fix item was the starter after one of our drives from AZ to OH. The next morning the truck wouldn't start (25 degrees F), so we took it in (magically, it did start in the afternoon when it warmed up to the low 40s). The tech, who I'm not sure if he's still there or not, noted extended start, so he replaced the starter, flashed the ECU (persistent high alc% on ffv without E85 in the tank), and replaced the battery for some reason. We work with a different tech at that dealer now, who talks to us about his plans before doing stuff, and he asks us a lot of troubleshooting questions - great guy.

Interestingly, and probably completely unrelated, our alc% reads 0% and has since he flashed our ECU. We should show _some_ amount of ethanol in the gas since it's added to all the stations here. Dunno what's up with that, but I assume we're running a tiny bit on the lean side as a result.


TL;DR it's a Toyota, no worries. (but the sound is irritating )

 

Well? so what happened with this? Was anything determined because I have the same problem with a 2014. My truck does this only cold and after a few minutes of idling it produces a knock. Not a loud knock but it is kind of a deep knock maybe like piston slap wrist pins is my best guess. It is not as loud as the truck in the video but it is bad enough to make me concerned! I'm running Mobil 1 0-20 and thinking of going to 10-30 maybe? Heck I don't know but one thing for sure I'm not taking it to the stealership we have the worst one in the nation >>> Northcut Toyota sorry sorry sorry no good %^$^%&(^&^*

 

I saw my son over Thanksgiving and asked him about the knock. He said it hasn't done it in a while. It would be a waste of time bringing the truck to the dealership unless the knock is present for a technician to hear and diagnose. Strange.

 

My '16 is doing this, too, & definitely from driver side. I started noticing it for the first time recently when the weather started getting colder. Only when starting, and it's fine once warmed up.

I've been using Mobil 1 0W-20 from Costco for the past 2 or 3 oil changes. Going to try Extended Performance next oil change as recommended above...see if that helps.

Also gonna check exhaust manifold for leaks, too.

 

possible fuel injector noisy but its fine

 

Update for those interested. Took mine into Toyota yesterday to have them take a look. They said it was coming from under the valve cover & definitely wasn't an exhaust manifold leak (though it does sound similar). They're going to replace all lifters and cam gears on driver's side & said it's covered under the powertrain warranty. Fingers crossed that it fixes the issue...and doesn't cause additional issues. The service manager said he's never seen this be the cause of the noise before. They have to order the parts & it'll be done next week. Stuck driving the go-kart till then ('03 Solara).

 

Did that fix the issue? My 2015 sounds identical!

 

Yes, that & a lot more. No more knocking since they fixed it in April.

Here’s everything they did (all covered under powertrain):

Their 1st attempt:
- Replace all lifters and cam gears on driver's side.
- Replace both timing chain tensioners & cam shaft pulley assembly.
- Replace valve adjusters
- Replace cylinder head gaskets
- Replace valve arm sub assembly

2nd attempt (still made the noise):
- Replace the head on driver's side

3rd attempt (noise on driver side gone - now noise on passenger side):
- Replace the head on passenger’s side

Fixed.

Diagnosis: the valves weren't getting oil like they should to top of engine.

It was a $12,000 warranty job billed to Toyota (would have cost me much more if it was a non-warranty job).

It’s pretty much a rebuilt engine. Crazy.

 

Wow that’s impressive. Mine is going in this week. Last time I had it in they didn’t hear it. I’ve had a rough stretch here with mine. Recently had the 3rd member replaced in the diff and a rear wheel bearing. Now need to get this issue resolved. Appreciate the info!

 

No prob - good luck to ya. If it helps (and if it's the same issue), the sound only happens when the engine is started cold. Once warmed up, it goes away & you have to wait till it's cold again.

Yeah I had my water pump seal go out shortly after this got fixed - replaced under powertrain, too. Very common for them to go - even at low mileage. They don't make anything like they used to - even Toyota. Cheap junk.

 

Ours has been fixed.

This was caused by a small leak in the timing chain tensioner on the driver side. Your dealer or other service tech can validate the cause on the driver side by observation through the oil filler location if they remove the filler tube and run the engine to see the tensioner action. This has to be done on a stone-cold engine. Letting it sit for a couple hours after running is not cold enough. Plan on dropping it off at the dealer the evening before, and have them pull the filler neck before starting it for the first time in the morning.

The reason the sound comes and goes is due to fluctuations in oil pressure - higher pressure pushes the tensioner hard enough to prevent the chain slap (functioning as designed). As soon as oil pressure goes down a little bit, the tensioner allows slack in the chain guide and causes slap (the tick noise). Ours was covered under warranty for both sides: tensioners, chain guides, chains, and whatever else is in there. When they opened it up, they found cam tower leaks starting so they covered that as well as a coolant diverter leak in the valley of the engine with a slow weep.

It was basically a top end rebuild.

We opted to have them replace the water pump and radiator hoses on our dime while they were in there, at the cost of parts and a little water pump labor.

Purrs like a kitten all over again.


If you have this noise, take it to the dealer and ask them to observe the tensioner through the filler (neck removed) on a stone-cold start up. I may see if my tech is on the forum so he can post pictures and video of the repair. Here are a few he sent me.

 

I just got my truck back last week from the dealer after over 3 weeks in the shop for this. They replaced all the mentioned items and put it back together with the timing off and bent several valves which resulted In them taking it all back apart to put in new heads and valves. Also did the cam tower seals. I hope this thing is good to go for a while.

 

@KevinK do you know how they fixed the coolant diverter leak? That would be good info for someone who may have a leak they cant trace and this ends up being the culprit, and I'd like to know so I can fix it if it ever happens to my truck in the future.

 

Great info in this thread. I hope this doesn't become more widespread.