Intermittent engine noise- diagnostic help? (1 Viewer)

[JohnPW]

My 2016 LC with @72k miles is making a chirping, squeaking noise under the hood, like a bearing going bad or perhaps a belt slipping. But it does this intermittently, especially after the truck has been running for awhile. It never does it when the vehicle is cold, so if I take it in for service I fear they’ll tell me nothing is wrong.

When it occurs it seems to be coming from the left side when standing in front of the truck (Starboard side in nautical terms). When it’s happening it’s worse with more throttle but is pretty continuous. But if I hop in the vehicle cold in the morning it doesn’t happen.

Any ideas on what is going bad?

 

[bloc]

I had over double your mileage but that sounds exactly like when my fan bearing bracket was wearing out. But I’d check the belt, all pulleys and the tensioner.

Fan support bracket & bearing - with high mileage check yours

2013 3UR-FE Landcruiser, just approaching 150k miles. I had a belt squeal on cold start at about 120k and installed a new OEM serp belt, which resolved the issue. At the time I checked the condition of the idler and tensioner pullies, as well as the fan support bearing (our fan doesn't run on...

forum.ih8mud.com

 

[HighRanch]

My 2016 LC with @72k miles is making a chirping, squeaking noise under the hood, like a bearing going bad or perhaps a belt slipping. But it does this intermittently, especially after the truck has been running for awhile. It never does it when the vehicle is cold, so if I take it in for service I fear they’ll tell me nothing is wrong.

When it occurs it seems to be coming from the left side when standing in front of the truck (Starboard side in nautical terms). When it’s happening it’s worse with more throttle but is pretty continuous. But if I hop in the vehicle cold in the morning it doesn’t happen.

Any ideas on what is going bad?

Spray a little water on the serpentine belt when the engine is running....I bet it will go away.
I think your belt is slipping and that can happen with weather and humidity changes.

 

[777Gage]

I've heard the same thing on my 2016 - very subtle chirp not quite a squeak. Took it to my local Toyota Dealership and they said it was the idler tensioners?? (If it remember correctly) They said it's a known 5.7 motor issue and they just had a Tundra in the week before for the same thing. They quoted me a $7k plus job....... (not a chance that's what's wrong at 69k miles)

I remember hearing it first at 60+k miles and it's never changed pitch or frequency. I've got 82+ on it now and still the same. I have a feeling that what @bloc recommends above is the culprit. Also changed out my oil to 5w-30 and significantly changed sound of the motor.

 

[bloc]

I've heard the same thing on my 2016 - very subtle chirp not quite a squeak. Took it to my local Toyota Dealership and they said it was the idler tensioners?? (If it remember correctly) They said it's a known 5.7 motor issue and they just had a Tundra in the week before for the same thing. They quoted me a $7k plus job....... (not a chance that's what's wrong at 69k miles)

I remember hearing it first at 60+k miles and it's never changed pitch or frequency. I've got 82+ on it now and still the same. I have a feeling that what @bloc recommends above is the culprit. Also changed out my oil to 5w-30 and significantly changed sound of the motor.

wtf else was on that repair quote? No way it was 7k for a belt tensioner.. unless they were suggesting it was the cam chain tensioners. Then they're lying to your face.

 

[JohnPW]

When it occurs it is pretty loud, you can tell something isn’t right. But other times it’s not there at all.

Thanks for the responses, I appreciate any ideas.

 

[bloc]

When it occurs it is pretty loud, you can tell something isn’t right. But other times it’s not there at all.

Thanks for the responses, I appreciate any ideas.

Does your AC blow nice and cold?

Does the sound persist if you shut off all climate control and the coolbox?

 

[777Gage]

wtf else was on that repair quote? No way it was 7k for a belt tensioner.. unless they were suggesting it was the cam chain tensioners. Then they're lying to your face.

I think your correct - cam chain tensioners - that sounds more like what was told to me. He said they are known to wear and cause a slight noise as described above.

I know it wasn't the belt tensioner, I've done those myself before.

 

[JohnPW]

Does your AC blow nice and cold?

Does the sound persist if you shut off all climate control and the coolbox?

I will double check tomorrow but I’m pretty confident it’s independent of the AC. I live in West Florida and the AC is running all the time, it’s near 80 and humid first thing in the morning and over 90 much of each day. I should have cut the AC when it happens to verify , but I know some of the time when you cannot hear a problem the AC is running.

 

[bloc]

I think your correct - cam chain tensioners - that sounds more like what was told to me. He said they are known to wear and cause a slight noise as described above.

I know it wasn't the belt tensioner, I've done those myself before.

I wouldn’t at all describe a chain tensioner going out as chirping or squeaking. It’s usually a loud rattle. You can find all kinds of videos of this on YouTube to compare sounds.

 

[777Gage]

I wouldn’t at all describe a chain tensioner going out as chirping or squeaking. It’s usually a loud rattle. You can find all kinds of videos of this on YouTube to compare sounds.

That's exactly what I did when I got back to my computer - I'm was (prior to selling) on one of the Tundra forums so it was easy to track down the noise issue and get some insight.

Definitely not what that noise is, thanks for backing up my research!

I do think it may be your suspicion above, the fan bearing bracket.

 

[KShorthairs]

My old one did this and it was tensioner and belt like Bloc said. Fixed it. With these high dollar cars, big spendy fixes run through your head. Cheap fixes happen too though!

 

[JohnPW]

Bumping this thread…4 months and 3,000 miles later I’m still struggling with this. I took the truck to the dealer in June but of course this intermittent problem wasn’t happening the day of my service appointment. They removed and inspected the belt, pulleys and tensioner and could not find anything wrong.

Since then the problem has been very intermittent…it won’t happen for weeks, then the truck will have a terrible squeaking noise, sensitive to RPM, that can last all day. The other day it started in the morning, continued all day after multiple stops and restarts, got worse under load later in the day when I was trailering my boat…then suddenly after restarting the noise was gone again. Like completely gone.

Now no noise for the past two days. Motor sounds perfect.

When it DOES happen, it’s always when the truck has warmed up…never on a cold start, which is the opposite of what I think of with a slipping belt.

Does this sound like a bad tensioner? I can have the dealer replace the tensioner proactively but I don’t want to fix what’s not broken. It’s impossible to predict when this problem will occur so taking it to a dealer will probably be another waste of time otherwise.

 

[Zill]

Since it’s temperature dependent, it’s either the belt or belt tensioner. You can have them replace both, but make sure you use OEM parts. My bet is the belt, but you might as well do both just to make sure. At 75k miles, you’re nearing the point where you should replace the belt anyway. Mine started squeaking at 70k miles but only when the car warmed up and on dry (not humid) days.

When taking it into the dealer, make sure to lock the glove box and take the key with you so the tech working on your car doesn’t break the blend door.

If that doesn’t fix it, next thing to change is the fan bearing bracket.

 

[yOHda]

I also am in the belt/tensioner camp. Leaning towards tensioner or another bearing tough. I have a Lexus engine swapped car that does this. Very annoying. Did not go away with a new belt. Goes away after a few laps when things are hot.

Curious if you have any coolant leakage under your intake manifold.

 

[TimCFJ40]

While your miles aren’t that high, the belt is 7 years old. I can’t believe the dealer took it off and inspected but didn’t replace at least the belt…

I’d replace the belt, tensioner, and idler pulleys as preventative maintenance every 100k miles, so you might as well do it now.