Rattle from exhaust

yamaimo

yamaimo

Ex. Club Member
Hi guys,

I have a problem with my 2001 k11 1.4. It started few weeks ago the exhaust pipe near 2nd catalytic converter rattles at certain rev. it is between 1640 and 1680 rpm. I suspected the heat shield so I put clips and even replaced old clips. However it doesn't cure the noise. So I took off the bottom half of the shield and checked the pipe but no obvious clue. So I start tapping the pipe to see if I can see anything loose or touching to the exhaust pipe. Strangely I still hear rattle as I tap even though I don't see anything moving freely and it stops only when I push up the rubber mounts.
I bet someone here knows the cause of this problem..
 
Thanks Frank. I always thought I was looking at 2nd Cat but if you say so it must be it. I thought the bulbous behind the box is mini muffler. No wonder the replacement pipe is cheap price for cat box from europarts..... So is it common problem? Can I do anything about this loose baffle before buying new parts....
 
i think you will find that sausage bit is a resonator mate, is yours like this but with a cherrybomb type thing half way down ?

$(KGrHqMOKpIFIjhQqCdiBSPCTqHzRg--60_57.JPG
 
Yes, Frank. you described mine perfectly. So these two section works different purpose? Everyday is school day ;).
 
Infinity, we might be talking about different section of muffle come loose so we have different rev to rattle......
 
I am trying to undo all nuts on silencer pipe but one of them is very stubborn and doesn't go. On top of this the pipe is hanging in the air. Every Time spana just twist whole section of pipe...... What is the best approach for this job?
 
I used a splitter in the end :). it is a very effective tool though i had to hack off taper of the nut in order to cut into the right in the middle.
 
my exhaust is new and quiet with stainless bolts and nuts. Well, for cuple of days tail end was held with jubilee clips..... I snapped stads :p. Only thing i wonder while i was taking old one down, the old gasket is badly delaminated and come apart as i twist... Is this possibly source of rattles? if so i might be able to explain why it stopped as i push up the pipe.
 
can say at what revs (no rev counter - still looking for the right dash to change this but never see any for sale!) but certainly at idle there is a bit, and pulling away I notice it if the window is open. other than that it's not annoying enough to do anything; perhaps I will one day now I know that it isn't a cat and so not going to cost a bomb to replace!!
 
If the rattle come from directly below you it is likely the silencer. i spent about 40quid for parts from europarts. if not check all heatshield on the front down pipe and main cat. My firts k11 had rotten bottom of the shield on the first Cat. if you like to find out the rev, i recommend android app torque or nissan data scan. all you need is to get a bluetooth obd2 adapter. i prefer torque because of dashboard layout. well, it is only available for android or pc though....
 
ECP have the centre section for £11.99 but has no silencer in it, or £15.99 again with no silencer not sure why there isn't one in the pipe? perhaps its quiet enough anyway. for the price of a few beers I reckon it would be worth doing :)
 
Had a right pig of a job getting that centre section out on my 1.3 1995....
Decided to take the lot off from the downpipe and then found the downpipe section bolt had seized and that snapped ...... so ended up having to remove the lot including the manifold ..ground off all the nuts securing it all together than wouldnt budge ...... .. then once all the parts are off the car it was easy to grind the old nuts off, pipe wrench works a treat with plenty of plus gas on anything that snaps or is seized...... so if your struggling ... my advice is take it off the car ... much much easier...... unless you have access to a ramp !
BTW yes the whole lot twists as your trying to undo it ... as said i just got the angle grinder out and got it off the car ... then sorted it !
 
Dont forget to get some exhaust paste .... you will need it to reassemble and get a good seal ... and dont expect to bollock it up and for it to seal ...i tried that and it leaks ...... i used the trolley jack to hold the middle pipe in the right place .... otherwise the top doesnt sit and seal correctly at the cat...dot forget the gasket and exhaust paste .. lots of ! .... you have to get it all in the right position ..... again bit of a pig to get right !
On the rear box i just hung it on the two outer hangers to get it in the right position .... once tightened up, fit the inner hanger..... dont forget the crush washer ring ... plenty off exhaust paste (which helps keep the crush ring in place while your tightening it all up)
 
TonySLX said:
Had a right pig of a job getting that centre section out on my 1.3 1995....
Decided to take the lot off from the downpipe and then found the downpipe section bolt had seized and that snapped ...... so ended up having to remove the lot including the manifold ..ground off all the nuts securing it all together than wouldnt budge ...... .. then once all the parts are off the car it was easy to grind the old nuts off, pipe wrench works a treat with plenty of plus gas on anything that snaps or is seized...... so if your struggling ... my advice is take it off the car ... much much easier...... unless you have access to a ramp !
BTW yes the whole lot twists as your trying to undo it ... as said i just got the angle grinder out and got it off the car ... then sorted it !
Click to expand...
Tony, how did you manage to extract the snapped bolts from the main Cat? I am keen on replacing those bolts to stainless one because they begin rasting badly. However I am worry about snapping off in the process. Or did you replaced whole thing??
 
If the bolts wont budge while under the car the way i did it was to grind the bolt heads off which allowed me to remove the exhaust front pipe and cat from the car .... it takes a bit of twisting with the passenger side jacked up to get the front pipe and cat out because of the brace ...... but there is room with a bit a jiggling and twisting about...
Once off the car i grinded off the back of the bolt which was well rusted on (where the thread goes through the cat) and you will find there is enough stud left to get a pipe wrench on at the front .... i guess due to the heat of grinding and removing all the rusty parts it actually came out really easily. ....... used some plusgas as well. Mines a 1995 and from the looks of it its the original front pipe and cat so if mine came off... yours should also ....
I did panic about halfway through and posted a message for a spare cat ..... but with a bit of patience and the right tools the bolts will come out.

This is all assuming you havent snapped the bolts very low down....... so if they are not budging i would reccomend grinding rather than trying harder as if they do snap low and dont leave you enough to get a pipe wrench on .... your buggered ....
If they are snapped low you could drill out but being honest i woul buy a replacement cat for £30 odd from fleabay at that point ... not worth the hours of drilling lol
 
Last edited:
Machinehead said:
ECP have the centre section for £11.99 but has no silencer in it, or £15.99 again with no silencer not sure why there isn't one in the pipe? perhaps its quiet enough anyway. for the price of a few beers I reckon it would be worth doing :)
Click to expand...
Machinehead, do you have mid section like the picture which Frank posted?
 
TonySLX said:
If the bolts wont budge while under the car the way i did it was to grind the bolt heads off which allowed me to remove the exhaust front pipe and cat from the car .... it takes a bit of twisting with the passenger side jacked up to get the front pipe and cat out because of the brace ...... but there is room with a bit a jiggling and twisting about...
Once off the car i grinded off the back of the bolt which was well rusted on (where the thread goes through the cat) and you will find there is enough stud left to get a pipe wrench on at the front .... i guess due to the heat of grinding and removing all the rusty parts it actually came out really easily. ....... used some plusgas as well. Mines a 1995 and from the looks of it its the original front pipe and cat so if mine came off... yours should also ....
I did panic about halfway through and posted a message for a spare cat ..... but with a bit of patience and the right tools the bolts will come out.

This is all assuming you havent snapped the bolts very low down....... so if they are not budging i would reccomend grinding rather than trying harder as if they do snap low and dont leave you enough to get a pipe wrench on .... your buggered ....
If they are snapped low you could drill out but being honest i woul buy a replacement cat for £30 odd from fleabay at that point ... not worth the hours of drilling lol
Click to expand...
Thanks Tony, I don't have right tools for those bolts yet so I will get these tools first.
 

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