Rod knock or Main bearing knock? - Toyota Yaris Forums

yaris2010RS · 12-17-2010, 02:02 AM

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 · 12-30-2010, 08:56 PM

Quote:

Originally Posted by 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?

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?

yaris2010RS · 12-31-2010, 03:22 AM

Quote:

Originally Posted by jabranko

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 · 12-31-2010, 04:10 PM

Quote:

Originally Posted by yaris2010RS

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 · 01-01-2011, 09:44 PM

Quote:

Originally Posted by slow.yaris

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 · 01-03-2011, 08:21 AM

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.

12-17-2010, 02:02 AM	#1
yaris2010RS View User's Garage Drives: no-longer-boosted '10 Yaris Join Date: Nov 2009 Location: Angus, Ontario Posts: 1,891	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? __________________ If it has boobs or wheels sooner or later your gonna have problems with it

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01-03-2011, 08:21 AM	#6
jambo101 Drives: yaris 08 sedan Join Date: Oct 2008 Location: Montreal Canada Posts: 1,286	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.