Rod knock or Main bearing knock?

[jabranko]

Hello Everyone, I'm new to this forum, but my buddy told me this was a good place to come for information and advice so here I am.

I notice this something that almost sounds like a clatter type noise, it's not extremely loud but it can sometimes be heard from outside the car or inside the car with the windows rolled up and radio off in a silent area. It's only when the car is in drive or reverse and only with my foot on the brake, if I let off the brake and let it start idling and moving the car the sound disappears immediately. Also it disappears if I put it in neutral or park. The other annoying thing is it comes and goes, but it usually doesnt happen from a cold start, only after driving around for a bit and coming to a complete stop (the sound doesnt start even when decelerating, it's only when the car comes to a complete stop and then it "kicks in") in a parking space or at a light and even then sometimes it doesnt occur which is why my last 3 trips to different toyota dealers have come back with no results because I'm having trouble duplicating it at the dealer every damn time. I found a post similar to this but there didn't really seem to be an answer.

From what I've read a rod knock will get louder as you accelerate so I don't think it's that because the noise completely disappears when I even tap the gas. I've found many rod knock videos online and my car sounds nothing like that but I can't find any videos that show what a main bearing knock sounds like or when it would occur.

So the point of this post and my questions are-
1.What kind of knock would only happen in drive or reverse at a dead stop and go away when accelerating? (if it is even a knock)
&
2. Do main bearings knock only when stopped in gear and disappear when accelerating? and would any kind of knock happen only sometimes? Under what conditions does a main bearing usually knock? <--These are the questions I really want answered because I can't find the answer anywhere online regarding main bearing knock.

[ilikerice]

worn or faulty motor mount maybe?.. not sure dude.. its hard to say if i cant hear the type of noise ur talking about.. good luck

[Grandieri]

Hope this might help........

http://www.yarisworld.com/forums/showthread.php?t=4919&highlight=reverse+rattle



6th post down talks about the TSB

[jabranko]

Hope this might help........

http://www.yarisworld.com/forums/showthread.php?t=4919&highlight=reverse+rattle

I've already looked into that and the previous owner (im guessing) already had it clamped to the bracket and it's definitely not that. Thank you though. Does anyone know the answers to my questions regarding main bearing knock in general? Thank you

[yaris2010RS]

the only ideas i have are

1. did u check the thread about the transmission cable holder hitting something? very vague but i dont know that issue exactly, i had come accross it before but cant quite remember the conditions

2. my moms camry has the same(ish) issues, the car makes an awkward knocking noise when in idle and only in drive or reverse and that sound has been tied back to the engine mount being warn out.

i personally dont think its anything as serious as a rod knock or bearing. the engine vidrates more at idle then running, as ur engine gets older its vibrates more at idle then when it was new. if anything has become loose in ur engine bay it with create a knock.

also; sometimes changing the tranny fluid helps.

[jabranko]

the only ideas i have are

1. did u check the thread about the transmission cable holder hitting something? very vague but i dont know that issue exactly, i had come accross it before but cant quite remember the conditions

2. my moms camry has the same(ish) issues, the car makes an awkward knocking noise when in idle and only in drive or reverse and that sound has been tied back to the engine mount being warn out.

i personally dont think its anything as serious as a rod knock or bearing. the engine vidrates more at idle then running, as ur engine gets older its vibrates more at idle then when it was new. if anything has become loose in ur engine bay it with create a knock.

also; sometimes changing the tranny fluid helps.

Thanks for the reply man. I really hope it's nothing serious I can't afford a new engine, lol.

Does anyone know about the main bearing question though? I havent been able to find the answers about main bearings in my original post and that was why I posted here wondering if anyone knew about them

[yaris2010RS]

Thanks for the reply man. I really hope it's nothing serious I can't afford a new engine, lol.

Does anyone know about the main bearing question though? I havent been able to find the answers about main bearings in my original post and that was why I posted here wondering if anyone knew about them

if its a knock at idle its not a bearing. reason for that is a bearing will not "knock", if a bearing were to make a noice it would basically be a whinning and would continue to get louder as ur rpms increase. it would never "stop" making the noise

[jabranko]

if its a knock at idle its not a bearing. reason for that is a bearing will not "knock", if a bearing were to make a noice it would basically be a whinning and would continue to get louder as ur rpms increase. it would never "stop" making the noise

Really? I thought it was wheel bearings that whine? I didn't think main bearings whined, i thought they knocked or thumped...that's what it says everywhere else at least.

[yaris2010RS]

it would thump when u innitiially change the load on the enigine (such as changing from park to drive) but it will not continue to thump and would whine and thump as the engine accelerates. at higher rpms u would also notice the engine would feel unstable.

with how u are describing it i highly doubt its something that serious.

block the wheels and put the car in drive with the e-brake up and look at the engine. try to see where the sound is coming from. hold things u may think will be hitting the engine or body. does it sound like a metal on metal sound or just hard force on a hard surface? feel the top of the engine while running and see if u can feel the knocking syncronized with ur ears

[jabranko]

it would thump when u innitiially change the load on the enigine (such as changing from park to drive) but it will not continue to thump and would whine and thump as the engine accelerates. at higher rpms u would also notice the engine would feel unstable.

with how u are describing it i highly doubt its something that serious.

block the wheels and put the car in drive with the e-brake up and look at the engine. try to see where the sound is coming from. hold things u may think will be hitting the engine or body. does it sound like a metal on metal sound or just hard force on a hard surface? feel the top of the engine while running and see if u can feel the knocking syncronized with ur ears

I did that - put it in drive with the ebrake on and was looking and listening under the hood (without blocking the wheels dumbass me good thing it didn't start rolling) It sounds like it is coming from the left side of the engine behind and below the alternator or behind the engine. I laid my ear onto the top of the engine and didnt hear anything besides the valves ticking away inside. I know that doesn't help much just figured I'd put that out there.

EDIT: The noise sounds like a hollow slightly metallic (i say slightly because it doesnt sound like metal hitting metal it kind of sounds in between plastic and metallic) sound that kind of goes cuh-cuh-cuh-cuh

[ilikerice]

heat shield coming loose maybe? rattling against the exhaust or undercarriage? when the engine shifts when its under a load could be barely enough for something to touch.. just a thought..

also im wondering if his CAT converter is about to kick the bucket.. just cuz u dont smell rotten eggs doesnt mean it isnt on its way.. but then again, check engine light would come on wouldnt it =(

[jabranko]

heat shield coming loose maybe? rattling against the exhaust or undercarriage? when the engine shifts when its under a load could be barely enough for something to touch.. just a thought..

also im wondering if his CAT converter is about to kick the bucket.. just cuz u dont smell rotten eggs doesnt mean it isnt on its way.. but then again, check engine light would come on wouldnt it =(

Hmmm...I wonder why it would only happen about 75% of the time then, sometimes the sound isnt there under the same conditions.

Just out of curiosity...What could cause the cat to go bad and what other symptoms would I notice?
no smell and no CEL

[jabranko]

BTW...I've been driving around with this noise for over a month and 600 miles and it really hasn't gotten any worse. If it was something like a rod knock or bearing issue or something like that it would've taken a crap on me by now right? lol crazy question I know, it's just very frustrating not knowing what it is and not being able to duplicate it at the dealership. The car is screwing with me I swear. haha

[ilikerice]

nothing really causes the cats to go bad.. they go bad over time. i honestly dont know what the cel is. but u post cat O2 sensor would read "inefficient" i think.. but dont get that confused with the A/F sensor or O2 sensor that says "open heat circuit" thats just the coil inside the sensor that heats it up for optimal use once the car is started. closed loop or open loop.. god i cant remember... sux not working at a dealership over 3 years ago...

ALSO id like to ad that certain vibrations can happen at certain RPM's.. try getting it to duplicate at a specific RPM also. i have a rattle in my crx at 4400rpm's and it drives me insane cuz thats my cruzin speed in 5th gear.. around 62-65 mph... still havent found that damn rattle either.. too lazy to get someone to ride with me

[jabranko]

nothing really causes the cats to go bad.. they go bad over time. i honestly dont know what the cel is. but u post cat O2 sensor would read "inefficient" i think.. but dont get that confused with the A/F sensor or O2 sensor that says "open heat circuit" thats just the coil inside the sensor that heats it up for optimal use once the car is started. closed loop or open loop.. god i cant remember... sux not working at a dealership over 3 years ago...

ALSO id like to ad that certain vibrations can happen at certain RPM's.. try getting it to duplicate at a specific RPM also. i have a rattle in my crx at 4400rpm's and it drives me insane cuz thats my cruzin speed in 5th gear.. around 62-65 mph... still havent found that damn rattle either.. too lazy to get someone to ride with me

The noise only happens at idle goes away when the engine is revved even a bit and then comes back when it settles to a stop. But that happening only sometimes is annoying because there's no way to duplicate it other than driving the car a bit with the tech there and then stopping and listening for the sound. I've done this 3 times already and for some reason I can't get it to do it when theyre in the car. ha go figure!

[yaris2010RS]

my winning vote is still something to do with something touching the engine. basically unless the car is hot and at its lowest possible idle is when it only makes the sound right? that is when the engine is the roughest. check the heat sheild, i think that would also be a really good place to start.

maybe someone who knows more about this can correct me, but i would also check the flexy thingy on the exhaust pipe. maybe one of the rubber bushings for the exhaust went bad. had there been any prior work done to the car within the last 3 months?

how many km on ur car? and when was the tranny fluid done recently?

[jabranko]

my winning vote is still something to do with something touching the engine. basically unless the car is hot and at its lowest possible idle is when it only makes the sound right? that is when the engine is the roughest. check the heat sheild, i think that would also be a really good place to start.

maybe someone who knows more about this can correct me, but i would also check the flexy thingy on the exhaust pipe. maybe one of the rubber bushings for the exhaust went bad. had there been any prior work done to the car within the last 3 months?

how many km on ur car? and when was the tranny fluid done recently?

Yes it's only when the car is completely warm and the idle is between 500-700. there are 53,000 miles on it and the tranny fluid i dont believe has ever been flushed from the maintenance records i have. i just bought the car two months ago. i got an oil change and fuel injection treatment done at the dealership 2 weeks after i bought it and that's all ive done. Should I have the tranny fluid flushed?

[slow.yaris]

it can sometimes be heard from outside the car or inside the car with the windows rolled up and radio off in a silent area.

rest is tl;dr

if that is what you have to do to hear the "problem" then there is no problem

[yaris2010RS]

Yes it's only when the car is completely warm and the idle is between 500-700. there are 53,000 miles on it and the tranny fluid i dont believe has ever been flushed from the maintenance records i have. i just bought the car two months ago. i got an oil change and fuel injection treatment done at the dealership 2 weeks after i bought it and that's all ive done. Should I have the tranny fluid flushed?

i dont know what the maintenance milage is for tranny fluid but 53,000 i think is early. u could get it done and it will probably make the sound less or gone for a while but that is probably not the issue.

check ur engine mounts and see how much the engine moves at idle and when shifting from drive to reverse. also check the air box (mine came loose and was making a scary sound) and check hoses for contact points (probably against the firewall) and check exhaust bushings

[slow.yaris]

i dont know what the maintenance milage is for tranny fluid but 53,000 i think is early. u could get it done and it will probably make the sound less or gone for a while but that is probably not the issue.

check ur engine mounts and see how much the engine moves at idle and when shifting from drive to reverse. also check the air box (mine came loose and was making a scary sound) and check hoses for contact points (probably against the firewall) and check exhaust bushings

If tranny fluid needs changing the first thing you'll notice is clunky shifting, not phantom clatters. Engine mounts will affect driving a lot.

Air box - maybe. Mine actually broke and was vibrating into itself. A new SRI fixed that. But I could hear that noise constantly pretty much, and didn't have to sound proof my garage and then hold my breath to hear it...

Seriously though if its something that quiet its probably a zip tie vibrating with the engine and hitting a coolant line or something even less dangerous...

[yaris2010RS]

If tranny fluid needs changing the first thing you'll notice is clunky shifting, not phantom clatters.

+1, the tranny fluid is not the issue, but at the same time, even tranny fluid with only 10,000km on it will make the engine vibrate more when in gear at idle then when not in gear.

but just keep looking for something vibriating and hitting something else.

[jambo101]

Any chance you could record the noise on your cell phone and then post it as a link?
No clue how its done but i have seen it done..

Any chance of it being part of the exhaust system doing some knocking when you come to an idle, i'd definitely give the whole system a shake as something may have come loose.

[mrbond]

lol i have this exact same problem. If you have the stock air box in place, check to see if that little snorkel is hitting the frame next to the radiator. I took off the snorkel and I haven't heard that sound again. Just a suggestion - better something cheap and stupid rather than something big and expensive.

[PROX4x4]

The noise only happens at idle goes away when the engine is revved even a bit and then comes back when it settles to a stop. But that happening only sometimes is annoying because there's no way to duplicate it other than driving the car a bit with the tech there and then stopping and listening for the sound. I've done this 3 times already and for some reason I can't get it to do it when theyre in the car. ha go figure!

Any updates? it seems like my car has the exact problem. It has 40K miles and under warranty.

[redyarisgirl]

Hi, I have an 08 Y and everything has been great up until about 10 days ago. I noticed a "high pitch" zing type noise, sort of random.. whether in Gear, Neutral, Reverse, etc. Now it has gone to a steady knocking, and yesterday for the first time, I could feel the knocking in the shifter. I have an appt with my Dealer,... who thought it might be the Alternator or Water Pump? I have been reading about the Alternator.. and doesn't seem at all what it is.... and the Water Pump.... I don't think so either (but what do I know) lol

Anyways... let the GONG begin

[Flipper_1938]

My wife's 05 corolla has made a similar noise since shortly after new. It hasn't changed in the last 150,000 miles.

[bronsin]

Hi, I have an 08 Y and everything has been great up until about 10 days ago. I noticed a "high pitch" zing type noise, sort of random.. whether in Gear, Neutral, Reverse, etc. Now it has gone to a steady knocking, and yesterday for the first time, I could feel the knocking in the shifter. I have an appt with my Dealer,... who thought it might be the Alternator or Water Pump? I have been reading about the Alternator.. and doesn't seem at all what it is.... and the Water Pump.... I don't think so either (but what do I know) lol

Anyways... let the GONG begin

Have your mechanic take the alt/wp/ac drive belt off. With the engine stone run the engine and see if the noise goes away. Dont run it any longer than it takes for the cool enngine light to go out.

If the noise goes away its one of those components gone bad.

[PROX4x4]

lol i have this exact same problem. If you have the stock air box in place, check to see if that little snorkel is hitting the frame next to the radiator. I took off the snorkel and I haven't heard that sound again. Just a suggestion - better something cheap and stupid rather than something big and expensive.

Mine was exactly the same problem and as you said I just super glued that little thing in it's slot and haven't heard the noise again.:w00t: