Today is the first time i drove my car since friday so my car's been sitting for about a day when i started her up today and i get a weird metal to metal rattle sound. I do a rev check to see if i hear any leaks but i don't hear any so i drive the Z and about a block later the sound goes away so i figure its nothing and i shouldnt have any more problems with the sound. but i get home after about 15 mins of driving and let her sit for about 2 hours and when i start her up again to leave i hear the rattling sound again and it goes away after it warms up again what could it be?

btw i have borla exhaust gruppe s ypipe, crawford cats and dc headers.

 

I think it is the crawford... my crawford makes that sound, it is not the housing, but inside the cat housing... it is way too far to send those cats back for me from downunder.... I only had it for less than 1 year, but it starts breaking up already.... at the brackets especially... fixed the cats twice already and now.. it breaks again with a small hole and the exhaust is leaking from there now... quite frastrating though....

cheers,

richie

 

Is it like a loos chain sound when the car start while under vibration or also when you are accelerating or decelarating? I have this too. Im so frustrated.

 

nope... for mine... it is more like a ticking sound from the cat (I actually jacked the car up to check that)... It does that not only at idle, but sometimes it has this ticking noise when I accelerate... and if you hold the cat by your hand, it will not make any rattle noise... as soon as you let go, you can hear it straight away... and all the bolts are secured (triple checked that already)

cheers,

richie

 

Does your rattling sound go away after it warms up?

 

I have the same sound you are talking about. I hear that it is just header ping and it is normal.

 

The thing is i've had my headers and hiflow cats installed for about 4 months and i've never heard this metal to metal rattlling sound before and now i have it. I tried to see if it was the crawford cat heat shield rubbing against the cars heat shield but there is plenty of clearance.

 

GTO2350:

Yes... when the car is totally warmed up... the rattle noise will be gone.. but sometimes it comes back... you can clearly hear it when you first start the engine while it is cold... I got this noise around half a year after I installed the crawfords cats, and I got the headers installed later on.. so it is definitely not the headers for my case!

Just got the hole on the cat fixed today.... I hope it will last longer this time... I was told that the brackets shouldn't be mounted there on the cats by many exhaust specialist, not too sure if that's true since I am not an exhaust specialist...

cheers,

richie

cheers,

richie

 

Mine is not a metal on metal noise tho. It just sounds like a small exhaust leek, but I have been told that it is normal with the headers and highflows.

 

i've solved the problem i losened the flange of the end of the ypipe that connects to the midpipe and it dropped the ypipe down lower tightened everything back up and the sound disappeared.

 

rattle came back!!

 

Update:

I spoke to Doug at Crawford..... Thumbs up for the 1st class service... Doug told me that the old cats tend to have some problem with the nismo exhaust and he will send me a new set shortly for me even if I am downunder... I highly recommend his biz to everyone!!!

cheers,

richie

 

did you ever find out what the exact problem with the cats?

 

GTO:

Most likely it is caused by the crack on my cat to have that rattle noise I am not too sure though... but my cat cracks, so gotta get it replaced...

cheers,

richie