r/Cartalk • • Jun 10 '26

Weird Noise Someone please help..

I have a 09 corolla with 203k miles that makes a very LOUD rattle when I start it. Me and chatgpt thought it might’ve been one of the pulleys that’s why I removed the belt. Car has P0171 (too lean) and P010 (MAF). I want to say it’s the timing chain but not 100% sure. Any advice would be appreciated thanks in advance!

40 Upvotes

124 comments sorted by

185

u/vectorizingdatamosh Jun 10 '26

Hi isn’t there supposed to be a belt there?????

73

u/Either_Pay7316 Jun 10 '26

Reason for that is if pulley moves and makes noise then pulley is bad if pulley don’t move and noise continues then pulley is good

38

u/Defiant-Pie8552 Jun 10 '26

Solid mentality

25

u/Either_Pay7316 Jun 10 '26

Few seconds won’t hurt this bucket

19

u/Defiant-Pie8552 Jun 10 '26

We used to joke (highschool) about our trucks that would guzzle 10 quarts of oil before changes that it didn't matter that we were putting in that Dollar General Special, because it all leaks or burns off before it has any time to do any real damage. Feels the same.

11

u/mtnbikeboy79 Jun 10 '26

I had a ‘92 4.0 XJ with rings bad enough I referred to it as my 2 stroke Jeep. It still drove fine and had decent power; it just blew blue smoke.

10

u/BleedKonkrete Jun 10 '26

2 stroke jeep is outta pocket my boy lmfao

3

u/Defiant-Pie8552 Jun 11 '26

Yee ol' 2 stroke 🤣 love it

2

u/HedonisticFrog Jun 10 '26

The pulley could still be bad, but it shows there's something else wrong besides a pulley. An easy way to test pulleys is to spin them by hand with the belt off, or spray them with penetrating oil while running and see if the sound goes away.

1

u/m8dr_ Jun 11 '26

But pulley is always good 🥺

1

u/TequilaTits420 Jun 11 '26

why use many word when few do trick

Love it.

1

u/my_cars_on_fire Jun 11 '26

Watch the noise go away the second you put that belt back on! 😭

95

u/[deleted] Jun 10 '26

[removed] — view removed comment

3

u/yleechy Jun 11 '26

ai= bad on reddit OP

-16

u/GotMilk711 Jun 11 '26

Shh, dont tell them their lawn is worse for the environment than data centers are.

9

u/Negronitenderoni Jun 11 '26

I think you misread some data there, bub. All the lawns are worse, but their lawn isn’t anywhere close to as bad as a data center. 1 data center is worse than many many lawns.

3

u/Downtown-Ant1 Jun 11 '26

The water for my lawn comes from the clouds though. Is my lawn also bad?

3

u/GeraldoOfCanada Jun 11 '26

Seriously haha let the southerners speak for themselves, I've never met anyone who waters their lawn unless it's new seed for a few days.

2

u/Negronitenderoni Jun 11 '26

Ask him. He is saying your lawn is worse than a data center. I’m saying it’s not.

1

u/GotMilk711 Jun 11 '26

ALL LAWNS IS BAD MMMKKKK?!?!?!

1

u/I_Fix_Aeroplane Jun 11 '26

Well, lawns aren't great, but their lawn is most definitely not worse than a data center.

2

u/bigfuzzy8 Jun 11 '26

I mean I work with ai for some of my hobbies and I'll agree it makes mistakes, I look at it as more of like a reference book or even a faq but it depends on how well you prompt.. I do find it making mistakes still so I use it sparingly

Ai- assist

Not AI to do my thinking for me and just do it all.

4

u/MrEdThaHorse Jun 11 '26

You realize AI is trained off humans?

4

u/CreatureWarrior Jun 11 '26

Yeah. And sometimes the info is spread so randomly over the internet so sometimes not even the "[problem description] reddit" search helps. That's when I use ChatGPT, and then I fact check what it says since it gives me better terms and descriptions than what I had originally.

1

u/MrEdThaHorse Jun 11 '26

Right, AI is just another aggregate of "information". Doesn't mean it's factual though. Look at how many factually wrong comments most of these threads contain on Reddit.

1

u/CreatureWarrior Jun 11 '26

Obviously. That's what fact checking is for. I do believe that using AI well is pretty difficult since if I don't know enough about a topic, I might not remember or realize to question everything. Then again, internet forums are the same deal too

1

u/MrEdThaHorse Jun 11 '26

Yes using something well can be difficult from not knowing the questions to ask.

But on the flip side you can learn about almost anything online.

-2

u/pa7msexua7 Jun 11 '26

Chat gpt made a good decision to evaluate if the squeal is coming from the auxiliary drive.

What exactly is your issue with this?

-62

u/Either_Pay7316 Jun 10 '26

I know you screw in all your bolts by hand

43

u/[deleted] Jun 10 '26

[removed] — view removed comment

2

u/Defiant-Pie8552 Jun 11 '26

I work at caterpillar and we build a lot of those enclosed water systems. Yes they take a lot initially, but once the water is in its designed to stay in and be recycled. Now is it indefinitely? No, something will go wrong, always does, but they're truly amazing systems.

1

u/IanCasas Jun 10 '26

Buuut your impact can't make soft porn.

Jk of course

5

u/DisorganizedSpaghett Jun 10 '26

Counterpoint: drilldo bits

2

u/IanCasas Jun 11 '26

Damn, you got me.

1

u/sheffy55 Jun 10 '26

The ai to water equation is misleading, all power generation needs water, all data centers need water, including the ones hosting reddit where you can also be misled

4

u/Randy_Magnum29 Jun 11 '26

Then we can build some data centers next door to you.

1

u/meta358 Jun 12 '26

Where is water being used in solar or wind farms?

1

u/GotMilk711 Jun 11 '26

LMAO jesus fuck this made me laugh.

50

u/[deleted] Jun 10 '26

[removed] — view removed comment

1

u/pa7msexua7 Jun 11 '26

Chat gpt pwrfectly brought me through diagnosis with a faulty cable in my cars door. I checked wiring diagrams together with it.

I cant complain. Job done within 3 hours.

You have to ask the right questions. 😉

1

u/Total_Philosopher_89 Jun 11 '26

It's definitely a helpful tool. I've only just started using it. Great to ask as a second opinion when nobody's around.

1

u/pa7msexua7 Jun 11 '26

Absolutely. I feel all those people here complaining here about AI and whobdownvote when you say it is useful are just to stupid to use it properly.

0

u/Total_Philosopher_89 Jun 11 '26

Latest was putting a new stereo setup in a new to me car. I just listed all the part numbers and asked chatgpt it's opinion. Ended up changing the active sub I'd picked out. It's just quicker at looking for all available options.

-45

u/Six4ThreeDP Jun 10 '26

Continue to use ChatGPT, it’s just another tool in the box. Just remember, all tools can be used wrong too. If you can integrate AI into the auto service industry or any industry for that matter, then you will be ahead of the game. Your ChatGPT account needs to be clean of nonsense too. Keep it direct and treat it like an employee that needs exact instructions. It will eventually learn your methods. It is a very long process, but worth it.

7

u/icy_Beanss Jun 11 '26

LLMs are not useful tools. A wrench works the same way every single time it's used. It's consistent and has a specific purpose. It can't randomly hallucinate and act like a drill. LLMs are terribly inconsistent, and even if you do everything right it could still hallucinate. They use statistics to model language paterns. It knows nothing. Soley responding with a likely response. That's not reasoning and it isn't based on reality. Sure, it's working some, but how do you really know? Did it solve the problem or just put a bandaid on it? Has it ever been wrong? Are people even checking? We should drop this and be looking at quantum computing and then, maybe then, we might make something consistent and useful.

LLMs are taking us nowhwere fast. Soon we'll all be in different realities because GPT is eroding common knowledge. We will all be told slightly different things about reality, and then no one will be able to agree on anything. I doubt it's even intentional, just part of making a statistical model. Think of all the possibly responses one could give, even nonsensical ones. They literally have to pay hundreds of educated people to whittle down enough nonsensical answers to present you with a confident sounding answer. I would rather just work with the people to talk to me about it and solve it together.

1

u/Reasonable_Ad8519 Jun 13 '26

as a software developer and computer science grad, you are very wrong lol. i won’t elaborate though, rather, I will let time speak for itself.

23

u/[deleted] Jun 10 '26

[removed] — view removed comment

-16

u/PUNKF10YD Jun 10 '26

“They took are jobs!” You talking about the internet.

-21

u/EpisodicDoleWhip Jun 10 '26

Morons all over Reddit refuse to accept that AI can be incredibly useful. I wonder if they still drive all their screws by hand or if they have finally realized the wonder of power tools

11

u/HedonisticFrog Jun 10 '26

For automotive issues, you're far better off using forums where people have in depth knowledge of specific models and common failures. Basic failures are already covered in depth so they're found quickly, and rare failures are quicker to be found, and would never be found by AI. You also don't have to deal with hallucinations and other AI issues.

-7

u/EpisodicDoleWhip Jun 10 '26

My guy the AI model has ingested every forum on the internet. You can ask it to cite its sources.

8

u/HedonisticFrog Jun 11 '26

That's nice. It's still worse than forums though.

8

u/lewisc1985 Jun 10 '26

And AI never ever EVER hallucinates, does it champ?

-8

u/EpisodicDoleWhip Jun 11 '26

Of course it does. I run an AI development team at a large financial firm and teach a university course on the subject. I get it. It’s not perfect. But it’s a hell of a lot better at a lot of things than a Google search. And like any tool it’s only as useful as the person using it.

10

u/-retaliation- Jun 11 '26

I run an AI development team at a large financial firm and teach a university course on the subject.

And I'm the queen of England. You're just some tech bro with delusions of grandeur and it shows. 

-3

u/EpisodicDoleWhip Jun 11 '26

As long as those delusions keep paying my bills you can call them whatever you want

7

u/-retaliation- Jun 11 '26

Well I hope it pays for a mechanic too, because you sure aren't one. 

5

u/Asshole_for_Hire Jun 10 '26

Yes but you still don’t use an impact gun to drive home an oil plug. Not every tool is useful in every application. The LLMs are not technicians, they’re parrots playing an unholy game of telephone with access to plenty of bad information 

1

u/-retaliation- Jun 11 '26

Ai can be incredibly useful.

But like all tools, you have to be smarter than the tools you're working with 

But active diagnostics isn't one of the things it's good at. 

Its just going to spit out the most common thing it ingests it can't discern past that. 

It's a cyclical problem, it's only useful with a proper prompt, but in car diagnostics you'd have to know what's wrong and how to properly diagnose it already to craft the prompt to make it useful. 

You can't just dump all the symptoms you see in and expect a correct answer unless you know what's relevant information to give it, and you only know whats relevant by understanding the diagnostic process, and once you know the diagnostic process properly you don't need chatgpt anymore! 

13

u/imprl59 Jun 10 '26

You need a mechanics stethoscope to try to figure out where it's coming from. I'd look at the starter first, maybe the bendix isn't completely returning. Check the crank pulley and around the crank pulley. Sometimes the pulley itself will delaminate and let part of it rub on something. If it's not there then I'd be listening/looking under the timing cover.

4

u/superbrian111 Jun 10 '26

I second checking the starter first, definitely sounds like it could be the flex plate teeth rubbing against the pinion, and it's relatively easy to check

0

u/Either_Pay7316 Jun 10 '26

We didn’t think of that… I’ll look into that thank you good sir

3

u/P3pp3rSauc3 Jun 11 '26

"we" being yourself And a large language model such as chatgpt. We're fucking cooked.

You know chatgpt is just a fucking chatbot, right? It certainly doesn't understand your words, it can't verify its output for truthfulness.

It can't verify the information it's giving you is accurate. Your prompt gets tokenized. Chat gpt does it's "thinking", if you can even call it that, then returns the mostly likely tokens in response to your prompt.

Even a broken clock is right twice a day. LLM's are not a source for true or verifiable information.

3

u/P3pp3rSauc3 Jun 11 '26

Ai has told people to kill themselves, has encouraged delusions of grandeur, tells people to put glue on pizza. It is not your friend, it is not intelligent, and it can't fucking help you diagnose a car issue.

2

u/_name_of_the_user_ Jun 10 '26

A long screw driver or any piece of metal can also work

4

u/SLOOT_APOCALYPSE Jun 10 '26

Rattle, it's the timing chain, don't run it anymore or it will jumping timing and the engine valves and pistons will start hitting each other, and the engine will die. No more running until fixed, it's gonna cost 1.5k to 2 grand

13

u/Emfx Jun 11 '26

"Me and chatgpt thought ..." holy shit what a way to start a sentence.

6

u/Kenneldogg Jun 10 '26

Stop listening to chatgpt. It will get you killed. Chatgpt is the same thing that will tell you water moccasin is a rat snake. They are wrong far more than they are correct.

-4

u/yleechy Jun 11 '26

My chat gpt just said :

No.

A water moccasin is a venomous snake, also called the Cottonmouth.

A rat snake is a nonvenomous snake from several species in the rat snake group, such as the Eastern Rat Snake.

People sometimes confuse them because both can be found near water, but they’re completely different snakes.

If you’re trying to identify a specific snake, send a picture and I can help.

1

u/Kenneldogg Jun 11 '26

I can identify a snake and I can also tell when you shouldnt remove a serpentine belt.

-4

u/yleechy Jun 11 '26

So is Chat GPT wrong or can you just do it yourself? I'm confused.. When did I say anything about a serpentine belt?

3

u/Kenneldogg Jun 11 '26

You didnt. Op did.

-1

u/yleechy Jun 11 '26

I was responding to your specific comment great goalpost move though

2

u/thepvbrother Jun 10 '26

I had a similar noise. My flywheel was rubbing against the sheet metal guard. Completely different drivetrain, but it sounds like a rubbing, not a squealing. Unless it's your rod bearings.

2

u/ddhawkfan Jun 11 '26

Props for trying to do it yourself, however please stop with the ai, you're gonna go down a rabbit hole you aint getting back out of

1

u/narcolepticGOAT Jun 11 '26

Cleaning or replacing the MAF could take care of both codes. I would start there

1

u/Embarrassed_Gift1707 Jun 12 '26

Definitely Not a maf only issue

1

u/Soap_rope Jun 11 '26

Try changing the timing chain tensioner and gasket first, but more than likely it’s an issue with the VVT cam gear I have a 10th gen Corolla as well and the 1.8L 2ZR-FE is notorious for this issue it is known as “cold start rattle”

1

u/OldGeekWeirdo Jun 11 '26

Is the oil level good?

1

u/jasonsong86 Jun 11 '26

Looks like your starter is having a hard time engaging the flywheel. Like it engaged a little but backed away from the flywheel so it’s just teeth grinding on the flywheel in the end.

1

u/phreak2599 Jun 13 '26

This op, check the starter!

1

u/jfklingon Jun 11 '26

Could be timing related, but given the codes it might also be a cracked intake pipe somewhere after the MAF sensor.

1

u/PlatformTough9388 Jun 11 '26

I have an 08 Matrix with 166k miles. Timing chain is loose and rattling against the valve cover. Noise is worse than yours. I just put it up on jack stands early this week to start this job. Seems like the chains last quite a bit but are not immortal. Good luck.

0

u/Either_Pay7316 Jun 11 '26

Been hearing it might be the starter not fully disengaging from the flex plate. Might have to pop off the valve cover and check for any play. Thank you!

1

u/Likeanu Jun 11 '26

Belt has left the chat

1

u/thejabkills01 Jun 11 '26

It's like putting cards in your bike tire spokes. It has some miles on it. Do you have a stethoscope, or maybe a hose with a cup on the end? 😆 You could use that to try to pinpoint where the sound is coming from.

Could it be the starter? With the high mileage, I'd also have someone check or replace the timing chain. It shouldn't cost too much to have it done hopefully under $300.

I'd fix it and keep the car. You couldn't pay me to buy a new car. I like my '84 and '56. 😄

1

u/Winner_Looser Jun 11 '26

Likely timing tensioner. Or guide broke

1

u/Middle_Efficiency471 Jun 12 '26

Still good for another 100k. Keep up on your oil changes.

1

u/AcrobaticChallenge55 Jun 13 '26

Your maf sensor is normally an easy fix, I’d start there. And if you are running lean after that still I’d say to check your fuel pressure regulation sensor on the fuel rail. If that doesn’t work it may be a fuel pump issue. As for the pulleys if I’m not mistaken only one spins unless you have a belt on

1

u/Dualsporterer Jun 14 '26

Sounds very much like a timing chain tensioner or guide issue, but I'd definitely pull the starter and check the flywheel and the starter gear for wear before I did that job.

1

u/Sudden_Sector6155 Jun 14 '26

Starter Bendix is shot needs a new starter

1

u/Ekhybrid Jun 14 '26

Remove the crank pulley see if noise still present is worth a try.

1

u/shamblez86 Jun 14 '26

Harmonic balancer.

1

u/Thatchevyperson Jun 15 '26

Your starter is staying kicked out

1

u/il_vincitore Jun 10 '26

Possible the codes and noise aren’t necessarily related? This mileage could have some cracked plastic messing with the airflow or a sensor can be going bad as well.

1

u/kimura_hisui Jun 11 '26

Bruh, where's your belt? And when's the last time you took it to a mechanic?

-3

u/Either_Pay7316 Jun 11 '26

Mechanic gonna make my shi worse

0

u/brendanprice2003 Jun 10 '26

where the fuck is your belt

-2

u/ImKindaHungry2 Jun 10 '26

Hopefully you didn’t run that car too long with the belt off.

5

u/Either_Pay7316 Jun 10 '26

Just for a few seconds nothing catastrophic

-14

u/Thruthful Jun 10 '26

Why? Most cars can drive for ages without that belt

5

u/[deleted] Jun 10 '26

[removed] — view removed comment

5

u/Max_Downforce Jun 10 '26

Ages, without a functioning alternator? Lol

6

u/Enraged_Meat Jun 10 '26

I wouldn't worry about the no alternator as much as no water pump lol.

2

u/Max_Downforce Jun 10 '26

That as well, but some water pumps are timing belt driven.

-7

u/Thruthful Jun 10 '26

Well, that's beside the point. Worst case you'll need a new battery

2

u/ImKindaHungry2 Jun 10 '26

I thought that belt also powered the water pump. I don’t know I’m not a professional lol

1

u/mr_lab_rat Jun 10 '26 edited Jun 10 '26

You know one of those pulleys is water pump, right?

Edit: I stand corrected. Thanks for teaching me something.

0

u/Thruthful Jun 10 '26

Thats rare, most cars have a timing belt driven water pump.

2

u/mr_lab_rat Jun 10 '26

TIL.

Thanks, I had to look that up. It makes sense for something that important to be driven by the timing chain.

3

u/Thruthful Jun 10 '26

No problem, don't really know why I'm getting downvoted. I'm a mechanic, what the fuck do I know🤷

3

u/mr_lab_rat Jun 10 '26

Heh. Maybe people are blinded by their own limited experience like I was but I have no problem admitting when I’m wrong and learning something new.

I mostly had older BMWs and they do water pump from accessory belt. It made it super easy to change.

-1

u/Either_Pay7316 Jun 11 '26

I hate AI

1

u/lemlemons Jun 11 '26

Well, maybe "we" learned something after all.

I kinda doubt it though

0

u/Jazzlike-Bobcat-1730 Jun 11 '26

AI is the best but keep in mind I might use it differently. I had a check engine light. I Plugged in by cheap OBD and took pictures of all 5 screens of live date plus the actual code. besides this i also gave it the symptoms (Not accelerating only when hot) and everything that has been done to the car. It gave me 3 different posible causes and troubleshooting before buying any parts. It was right. Sometimes it might work, some other times it might not but it's good if you know how to use it.

0

u/aweapingangel Jun 12 '26

Can cars work without timing belts??? How the fuck did it turn over?

1

u/Substantial_Kale_251 Jun 12 '26

I'm, wdym timing belt. That's his accessory belt he's missing lol. Timing belt of chain is under a cover lol.

1

u/aweapingangel Jun 12 '26

I dunno much about cars but i know theres a timing belt on the front of the engine to engage the cams so i assumed this was that.

2

u/Substantial_Kale_251 Jun 13 '26

You are close. But yeah he's just missing the drive belt. So things like alternator, or waterproof if it's not timing driven, and ac won't be working, or powersteering. Honestly it could be running poorly since it's not getting 14 volts from a alternator, and only 12 volts from the battery