Exhaust Heatshields (under the car)

Site Subscriber Joined: 29 Jan 2005 Posts: 1108

Okay, here's my dumbass question for the day. How important are these exhaust heat shields? Underneath the car that sit above the exhaust pipe y'know. Cuz I'm assuming they are there for a reason, right? I took me car to an exhaust & tyre place a few days ago to see if they could find my rattle, and they couldn't find it anywhere. The exhaust is miles clear of everything, so it isn't that touching the car anywhere like I previously thought. So the guys at the garage seemed to think it could be the exhaust heatshields rattling against the car body with the vibrations, and suggested to take 'em off completely. This seems daft to me? Just checkin with you lot how much of a retarded idea that is, cuz I got no idea. You might say "yeah fuck it, take 'em off, they're no use" or as I'm expecting you might say "the garage are a bunch of remmers and leave the damn things on" lol. Just checking before I take it back in tomorrow like.

But if it ain't the exhaust hitting anything, and then it also isn't anything else hitting anything..............then it's gotta be something IN the exhaust. Or the exhaust might be fucked I spoze. Dodgy weld or something. Real tinny rattling noise. Won't try and explain it on here cuz it's pointless anyway. Confused

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

take it off if ye want but they provide a silencing effect as well as reflecting heat from the handbrake cables etc.

would maybe be an idea to thump a few heatshields to see which rattles

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

also make sure the handbrake cable are cable tied to the rear beam and that the spare wheel brackets not rattling

Site Subscriber Joined: 29 Jan 2005 Posts: 1108

Will do. Cheers Chris

Site Subscriber Joined: 05 Jan 2005 Posts: 589

On my ph2 1916v i had a rattle that i could not find for months, i eventually tracked it down to a 3"ish length spring that if i remember correctly was something to do with the brake compensator (Chris would know for sure) instead of being held in postion by its springed force, it had just came loose and was moving about, and giving me not a loud noise, but i could hear it rattling about as i drove with the window down.

Site Subscriber Joined: 29 Jan 2005 Posts: 1108

Hmmm that sounds like the same kinda noise. I can't hear it with the radio on and windows up, but turn the radio down and open the window and it's there. Drive down a narrow street and man it's noisy then, echoing back at me like. But thismorning I discovered something else. It doesn't rattle when you first start the car. It's rattle free for the first 5 mins or so, and once it's warmed up a bit then the rattle starts. So something to do with something changing shape with heat methinks. Ah well, will see what the garage says tomorrow. Cheers Roddy

Forum Moderator Joined: 18 Feb 2004 Posts: 7432

does it rattle/rattle more, when turning a corner one way but not the other?

Site Subscriber Joined: 29 Jan 2005 Posts: 1108

No it's just the same constant noise. It happens in every gear at just over 2,000rpm, so that must produce the resonant frequency of whatever's rattling or something. Also it happens whenever you come off the throttle but are still in gear if that makes sense. Like coming up to turn into my house in 2nd gear just cruising along, not really on the throttle, it'll be rattling constantly, doesn't matter what rpm then. I'm sure now thinking about it.....it can't be the exhaust tho, cuz when it's rattling, if you grab the exhaust and hold it tight and try and move it around etc.......it's the same rattle while ur doing that. You'd think it'd change if you disturbed it like, or at least go a bit quieter while you were holding it.

Ah well, am takin it into garage later on, so will see what happens.

Forum Moderator Joined: 18 Feb 2004 Posts: 7432

simonds1 wrote:

Also it happens whenever you come off the throttle but are still in gear if that makes sense. Like coming up to turn into my house in 2nd gear just cruising along, not really on the throttle, it'll be rattling constantly, doesn't matter what rpm then.

This suggests it is the zorst rattling against the heatshield somewhere, as the engine rocks forward on overrun it will move the exhaust slightly and bring it into contact

Site Subscriber Joined: 29 Jan 2005 Posts: 1108

That's what I would've thought. When I took it into garage few days ago, I went up on the lift in the car, so I could rev it and get it to rattle while the guy was havin a look underneath, so I didn't really get to have a look. I reckon I could've spotted it, I got a good ear for things like that. And he was probably deaf lol. But he said it was miles clear of everything and so it was a problem with the actual exhaust. So I then said well I need to find that out for definite cuz I ain't goin through the hassle of getting a replacement exhaust from Mongoose if it is just rattling against heatshield or something. So they said to bring it in today and they'd have a proper look, cuz they didn't have time when I just popped in before.

Forum Moderator Joined: 18 Feb 2004 Posts: 7432

its one thing to rev the engine and another thing to load it. Engine will move a lot more under load...

Site Subscriber Joined: 29 Jan 2005 Posts: 1108

Yeah but it rattles when you just rev it standing still. I can get it to rattle just by holding it slightly above 2,000rpm when I'm parked still. Just constant bbbbzzzzzzzzzzzzzzzzzzzz then.

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

its probably the downpipe heatshield.

its meant to be held on by 6 bolts, they all corrode and break away and it rattles.

big jubilee clisp round it shoudl shut it up.

My old hatch uses to buz constantly around 3krpm because of it. terrible on the motorway

Forum Moderator Joined: 18 Feb 2004 Posts: 7432

Mate, mine does the same, it did the same on the hatch till i faffed about with it to clear. Its rattling against the furthest back corner of the heatshield, or the torsion bar, or the bit of the shell that goes diagonally up and and back from the front of the wheelarch.

Id put money on it

Otherwise, its something else Razz

Forum Moderator Joined: 18 Feb 2004 Posts: 7432

Deffo not the downpipe heatshield on mine, the sound comes from somewhere between the torsion bar and directly under the handbrake lever.

Site Subscriber Joined: 29 Jan 2005 Posts: 1108

probably 'something else' lol. I'll suggest all of those to them anyway. And they'll just be like "yeah, yeah....yeah...." and not listen to a word I'm saying Rolling Eyes

Site Subscriber Joined: 29 Jan 2005 Posts: 1108

My sound is somewhere around the cat.......or de-cat in my case. My dad was lookin under the car with me and he was like "is that your cat?" and I was like "um....er......yeah" and he was like "oh, never seen one like that before" lol

sshhhhh

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

under the car theres only the heatshield on the downpipe, the heatshield on tye bulkhead, the heatsheild on the floor from above the cat to just before where the handbrake cable outer clip in (caovers the striahgt bit of the centre section).

shouldn;t be any more shielding on the car.

the heatshield centre section bit can corrode and the bolts no longer hold it properly. normally the bolt seize in the captive wing nut thingys as well

Site Subscriber Joined: 29 Jan 2005 Posts: 1108

Right, just been to garage. Ummm.....basically......if I'd have wanked in my own face, that would've been more useful y'know. What a bunch of remmers. Here's the conversation;

Me: Hi, I came in on tuesday with my rattly exhaust and you said you'd have a look at it today?
Garage: Okay yeah, put it on that ramp there
*me drives car onto ramp*
Me: Shall I get it to rattle now so you can see what sort of sound it is and try and tell where it's comin from?
Garage: Nah, I'll be able to tell straight away just by looking
Me: Right okay
*guy starts bending heatshield nearest to the cat out of the way*
Me: Um, yeah I've tried that before, it's not that. The guy I saw here on tuesday also said it isn't that
Garage: It'll be that, trust me
Me: No it won't be, it's nowhere near it, and it ain't that sort of noise anyway. Do you want me to rev the car now so you can have a look and see if it's that?
Garage: No, because I know it is that
Me: Right
*guy starts hammering it out of the way*
Garage: Right, that'll solve it
Me: Okay, can I try it now to see if it's solved it?
Garage: No, you'll have to drive it and see what it's like
Me: But it rattles as soon as I start it up, I'll be able to tell if that's solved it or not
Garage: That will have solved it
Me: Riggghhhttt. Cya then
*me can't be arsed with him anymore*

So that was great. I thought I'd have a look again myself when I got home. Didn't have any luck, but I took this pic, which is rather interesting. Well, maybe. Those of you who know the underneath of the car better might actually be able to tell what's going on there, but I got no idea! I was trying to point the camera up where the downpipe is, if that makes sense. Anyway, I got this pic, and what in the hell are those two things?? The one at the top looks like a big ass mother fucker screw that somebody's rammed through there, and then the other one is just a loose bolt that is attached to......I have no clue?

Any views on that pic would be appreciated. Cheers Confused

Forum Moderator Joined: 18 Feb 2004 Posts: 7432

the cable thing is the starter wires.

The bolt is a bodge, should be a long one going right through the bracket, through the gearbox lug and a nut on the other side, like the other one.

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

starter solenoid wire.

The other is the rear mount bracket, i would imagien looking at it its loose, which will be causign a rattle.