Hi everyone. I got another wonderful problem discovered coming home from work today. I hear a loud and constant high pitched metallic knocking noise from under the car. I cant hear it that much when the car is moving but it gets loud when stationary. When I got home, I popped the bonnet, the noise does not seem to be coming from the engine bay, but it is loud under the car and towards the middle section. I cannot determine the exact location with all the resonance bouncing off the floor. I am wondering out loud here, could it be an exhaust thing or could it be something more serious? Ideas anyone? (PS I know this is a stab in the dark but more ideas means I get more clues on what to look for, cos I dont have much of a clue atm.) Thanks in advance.
Auto. The stuff done will be a new radiator, overdrive and underdrive pulley and new cam gears. Nothing touched under the car.
I will say the knocking is constant, almost in time with the droning of the exhaust. Don't tell me it's the gears? (face palm and moan)
sounds like a tranny problem, if it's not coming from the engine bay, and still happens while stationary. Either that or the starter motor solenoid could be buggered and not disengaging after starting. (this has happened to me before and required a starter re-kit) This is the same noise i encountered... ...but apart from that, it could actually be an engine related issues and throwing the sound backwards if possibly from the bottom of the engine somewhere. Ideally, either get the car on a hoist/ramps/chassis stands and start the car to enduce the noise, and pop underneith while running to narrow down the noise. This will help massively. *EDIT* Also read my other post after hearing of that latest info the O/P posted.
after reading this post, it sounds like it could even be an exhaust leak. It makes a "ticking" noise when at idle.
In gear (D) as well as out (P), or just whilst in gear (D)? Anything wrapped around the driveshaft/centre bearing?
Ok I got another clue. I went down to start the car and listen out for it again. It seems to be quite indistinct now. However, after a drive round the block, the noise is back and louder.
In any gear I believe. As long as the car is stationary, I can hear the noise. Not so distinct or I cant hear it when moving, either the noise is drowned out by the engine or road noise or it just disappears moving. Nothing around the drive shaft I think? I didnt do anything to that, so it is possibly in stock form.
exhaust can expand under heat, and create leaks when normally not there if there's a gasket/leak issue. Maybe something to consider. Also, if you still retain your heat shields around your exhaust, they may be slightly out of shape and vibrating on your exhaust too. Like i said, jack her up and start it up. This will help audibly locate the issue which may help narrow it down for you.
probably exhaust then. start the car and block the exhaust with your hand and see if the noise changes
How about a rock or two stuck between the exhaust heat shield and the car? Been down any gravel roads lately?
Nope. Anyway, thanks for the ideas guys. I am hoping it is an exhaust thing (which is wayyyy cheaper to fix and hopefully nothing to do with the tranny). I will be taking the car down to Joe to have a look see. Hopefully it's nothing serious. Will post the update when we find out the cause.
mysteries of the Z - I create them - is that experience? Crikey This is a "sounds like my type of post" - I can help here lol Dont slap me for this - but since this a "wild guessing" type of post (like I said - it sounds like one of my posts - lol) My guess is - "Its a piece of exhaust/ suspension metal hitting together under the car near the rear!" If you already slapped me - then expect one back from me as well cause I'm really just backing your judgement, eyes, ears, senses and the tests you've done better than my imagination could possibly fathom or have even come up with - yep its a my type of post for sure. I would've said "its something metal from between the front fascia and the rear exhaust pipe" - so I figured since were betting wisely - your guess was percentage wise, a lot better than mine. I hope we are the winners! lol Hmmn - You need a ghost spirit to drive your Z while you walk beside it and listen - they can be hard to find - anyway goodluck to us tommorow (See my latest secret post crying out for help posted.........tommorow) its 2am - shiftworker barchicking forumites should get Z TT's for free from the government...........as a spare for when I start to fix things Goodnight and Best of luck tommorow Linda "If its broken - Its cause I fixed it - Linda"
And the answer is.... Busted CATs. Apparently, the bits in the CATs gotten loose hence the rattling and knocking like sound. Anyway, 1/2 points for those who said exhaust related problems. Now, to the RSPCA to adopt some kittens......
