Rattle in engine bay

[jako999]

Hi all I have a loud rattle vibration in the engine bay its been there for sometime but its getting worse its very mild if you just rev the engine but when you pull off it's loud and in the first few gear changes. Ive had a good look and I've found the heat shield over the turbo is a bit loose but not to bad the only other thing I can find is a hair line crack in the lower mount but again you have to push the exhaust upwards real hard and the crack only opens by 1/4mm so I don't think its that, I cant really find anything else but i'm sure its to do with the exhaust. The only other thing is that the out pipes have always been slightly to the left hand side in the valance and after looking at it pull away the exhaust drops a couple of centimeters, if I put my foot on the out pipes the noise is greatly reduced. I think the can it self is ok. Any ideas?
Thanks

[Evilution]

Loose CAT?

[Thrumbleux]

With the handbrake on and in gear, dab the throttle as if trying to move off. If you feel vibration it's probably engine/transmission mount. Do it in first and reverse - if you can feel it and it's worse in first then near certain mounts.
Could just be exhaust - crack will need attending to ASAP or it will split all the way.
Recent oil change? Wasn't jacked up by the engine was it?....

[jako999]

No I did the oil change it was jacked as it should be. I am getting the exhaust mount welded asap. I have tried the first gear but not reverse and the rattle is there but had another good look to and the mounts all look fine it doesent look an easy job to change them?
Thanks

[Mad smart person]

Greetings, do you own a long screw driver? One that's about 12 to 18" long. There's a warning/caution here for what I'm about to suggest, keep the screwdriver away from moving parts and spark plug leads / plugs. If what I've just said is not obvious to you, then don't proceed. If you understand the hazards involved, then continue. Put the car in an 'open' area, with excellent ventilation IE, not in a garage or enclosed space. Plenty of light would also help. Apply the hand brake and chock the rear wheels. Open the engine cover and secure it and the carpet, so they won't get in the way or move. Start the engine and leave in 'N'. Take the screw driver and place the 'tip' of it on any 'suspect' part of the engine. (By suspect, I mean, where you think the noise may be coming from.) Ensure the blade tip will not move. Now place your ear on the plastic end of the screw driver, any noise will be heard, the louder the noise, the closer you are to the problem. There are hazards involved with this procedure. Please do not try unless you understand what you're doing. It will though, help you narrow down where the noise is coming from. Does the noise, by chance, sound like a noisey tappet? If so, I'd suspect that, that's just what it is. I'd suspect one of the rockers has 'rocked' over and although still doing what it was designed to do, is making the noise. Cheers, Ian.

[Thrumbleux]

I have tried the first gear but not reverse and the rattle is there

The test was to whether the noise had a direct path to the chassis not whether it was there or not - we already know it is. Could you feel anything through the car?
That test isolates mounts from exhaust and thus halves the task.

[jako999]

There is no vibration in the car you can just hear it. today I have been back under it and all over the engine bay an either bent all any little bit of metal out of the way, padded out anything that can touch the body and cable tied anything that can move and touch the body out of the way.

[davros7760]

Don' t want to hijack your thread but we might benefit each other.

I have been trying to track down a rattling sound in my roadie for a while (tbh its driving me nuts)

It is an intermittent rattle almost as if there was a loose tool in the engine bay.

The car drives, handles and brakes normally but everything checks out. By chance I ran the engine
whilst on jacks and couldn't replicate the problem. Have you tried that?

Also, can you hear any rattle when the car is stationary?

[Thrumbleux]

There is no vibration in the car you can just hear it.

That probably eliminates the mounts. If the mounts were worn allowing the exhaust to contact the chassis - you would feel it. If they were worn through to the metal - you would be hard pressed not to feel it!

today I have been back under it and all over the engine bay an either bent all any little bit of metal out of the way, padded out anything that can touch the body and cable tied anything that can move and touch the body out of the way.

If you think it's from within the exhaust (loose cat/baffle) try holding very firmly a heavy damp rag against the exhaust. If the sound quietens then it's probably from inside the exhaust. Take care not to scald yourself if you do this and only with the car stationary - fire risk!
It could just be something rattling in resonance with the engine (your efforts in securing everything should have it licked if so). I once had the most god awful rattle on mine - from the warning triangle box behind the seat.

[davros7760]

The illustrious Scott managed to track down my mysterious rattle in 2 minutes - though to be honest we were given a big clue purely by chance. One of the bolts securing the cross member to the DeDion tube was loose by no more than 2mm, allowing some play when moving. My visual inspection(s) had been on my back on a trolley, placing me directly underneath, where the gap isn't obvious. Now I have to monitor the bolts on a regular basis to see if it was a one-off.

Worth a check - you might have the same issue?

[jako999]

Hi all thanks for all your help I will get under it again in the next few days and have another good look, I will have to get the exhaust bracket welded just to rule it out but i'm sure its not that. I am going to try a small block of wood between the turbo and the heat shield to see if that helps don't worry I wont go far other wise I wont have to worry about the rattle just the fire.