Scary noise on cold start
 

Hello,

I’m slightly worried, as I just got a very strange noise.

I started my 86 (1 week since last use) inside my garage (temperatures are pretty high for winter, 15°C/59°F).

Motor revs to 1500, as usual, then I get a loud sound « ta-ta-ta-ta-ta-ta-ta ». Kind of like firecrackers, or when your exhaust has holes, but I’d say higher pitched. A bit metallic, but maybe that’s my mind. And definitely loud enough to be heard over the motor, with doors and windows closed.

Anyway, it lasted maybe a 5 seconds, while I was WTF-ing, then it disappeared, RPM revved down to 1000, and I did not hear it anymore as I went shopping.

How worried should I be?

Edit: car is 2012, stock, and I pressed the clutch pedal during the sound and it did not seem to affect it.

What is the mileage (kilometerage?) on your engine? A video with sound would be helpful.

~82000km. The recall was done last December.

I’ll try to start it every few days, with a phone ready to record, in case it repeats.

What oil are you using

First guess would be a rod knocking until the oil pressure built up but your engine mileage is rather low for that.

The one that Toyota puts in at maintenance, so 0w20 iirc?

Hmmm yeah plenty thin. You had the recall done and that's a red flag. If they let silicon get in the engine it may be clogging things up and compromising the oil flow. Keep an eye on it. Not much you can do if that's the case. Yes try starting it often to keep a film of oil on the bearings

If it keeps doing it, try priming the oil pressure when starting it cold. You do this by holding the gas pedal down when starting the car. It will crank, but not start until you take your foot off the gas. Let it crank ~3-5 seconds to let the oil pressure build up, then let it start.

Will check back for the recorded sound.

What part of « ta-ta-ta-ta-ta-ta-ta »,, don't you understand?

:rolleyes:

Maybe a piece of the cat honeycomb broke loose

At this point, all I have is the mental picture of a man saying it with a French accent.

.

as a professional wrench, there are at least 5 normal issues that make this kind of noise. Its definitely a relevant thing to want to listen to it.

For example, is it a lifter not pumping up quickly? Or an exhaust manifold leak? Or a heat shield? Or an item stuck in the belt that flung itself out after a bit? All completely different diagnosis and prognosis. All to Tatatatatatata

could also be an annoying passenger, a passing truck applying their jake brake, or full-auto gunfire.

As a non-professional wrench, I understand.

I was "jest ah messen wich" ol Ultramaroon - ;)

I've had tapping on startup once, it was the day after my car had been picked up J02 valve spring recall (3 years ago) and the fuel in the tank had been sitting for a month. It was also the middle of July in a 100+*F. I think it was a fueling issue for one reason or another but given it was right after the recall service, can't throw that out.

Hello again guys.

After recording each start for ~10 days, it finally happened again (after leaving it outside for a day and a half), and I was able to capture it :

https://youtu.be/TX3mLvO2FZk

It starts at around 15s and is quite loud (before that there is the sound of rain). No sure how to describe it, kinda metallic vibration/creaking?

Scary noise on cold start
 

That sounds like metal on metal. First thing I’d do is check the oil pressure on idle.

https://i.imgur.com/DKn8NH2.png

https://youtu.be/jdccNAOvPHg

Should have bought a VW.. more da-da-da-da......

And then for the computer nerds on the forum:

https://youtu.be/Jb5NTwAEi2w

Excuse the quality, it is Microsoft after all...

I am certain that it's not engine mechanical. Other than that, I could make some wild guesses. It does sound like a metallic creak.

Thanks for the feedback. That would be quite a relief ��

Where would you look at first? I was thinking loud like that it could come from somewhere along the exhaust line, like something loose or a catalytic converter starting to die? (I know from experience catalytic converters can make a metallic rattle when they start to break, although 80k km seems a bit early). Bottom inspection first?

I’ll keep in mind the oil pressure check too, but for now I don’t have the equipment…

Can you shoot another video looking under the hood (bonnet). Maybe look specifically at the belt tensioner. Also is the sound coming more from one side of the engine or the other.

My first thought was exhaust heat shield rattling or touching part of the frame.

I’d say from the driver seat, it felt like it came more from the passenger side, but it’s hard to tell as it lasted only a few seconds.

I’ll get the car back in 2 weeks, so I’ll do another video then (and maybe get someone to start it while I film/listen from outside).

I should also have access to a pit then, so I’ll look at the visible exhaust parts.

Thanks!

Noise with hood open :

https://youtube.com/shorts/hiH5tLVjzGo

It's definitely some sort of rattle outside of the engine. I don't think it's the AC compressor itself but notice that the rattle stops as soon as the compressor quits running. This is most likely because the engine quits laboring to drive it.

It's an odd one! Maybe a loose engine support. It's loud!

Yeah, it seems to start when the AC clutch pulley engages for the first time, and stops when it disengages, I made another video focusing on it.

https://youtube.com/shorts/NRkrvibHYvw

Run the engine with the belt off. See what happens.

Removing the belt off seems a bit of a hassle? No idea how to do that (and put it back properly after?)

I've turned off the AC, so far no noise at all the few times I have started the car.

How willing are you to find the issue? Just take it to a dealer if you're not gonna try to diagnose it yourself. Taking off the belt isn't difficult, and a quick YT search will show you the process.

You're coming to a forum to ask for help, help was given, and you're like "nah that's too hard, why can't y'all immediately diagnose my car based on my very detailed description of 'ta-ta-ta-ta-ta'?"

Learn to work on your own platform. It'll help you in the future, and, in turn maybe you'll be able to help someone else. Otherwise, just go to the dealer and pay $200 for them to half ass the diagnosis themselves. :iono:

hahahah, ahh, gotcha

one of the reasons I bought this car is that its SUPER easy to work on, at least under the hood. The belt is nearly as easy as opening the trunk. Im not kidding. Put a tool in the tensioner, and detension it. then slide the belt off. Start the car, and listen to the noise or lack of it. Put the belt back on and try again. This really is the only way to isolate if its related to anything spinning by the belt

It is ridiculously easy to remove the belt on this one, especially if the stupid noise generator has already been removed.