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My elise is making a noise. what do you think it is?


... ohhh... just kidding. But really, I have a noise coming directly from the engine and it is ugly.

Its hard to describe. It happens if i keep it at about 2000 - 2500 RPM. Its a vibrating buzz sound and it sounds like it is coming right from the far side of the engine (near the spark plugs). It will momentarily sound worse once i take my foot off the gas and the RPMs fall. At idle, the noise is not present and if i drive it a little harder there is no noise.

Now dont get me wrong, i have no problem driving it hard to temporarily rid me of the noise, but i need a fix. Thought it might be a sheer panel thing, but i checked, that is fine and the diffuser is not the culprit. I had a buddy keep it at 2k rpm and traced it directly to the engine.

No CEL No loss in power from what I can tell..

its stock 2006 elise. 34k miles.

Any ideas? the sound is really embarrassing when it pops up in daily driving accelerating and decelerating within those RPMS. :wallbang: And we are talking loud enough to hear over my upgraded audio, exhaust, other car buzzes and all other pleasant road noises.
 

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Check your heatshields around the exhaust manifold. One of mine had sheared completely through and had a nice "car falling apart" rattle. In particular, there is one on top of the manifold and bottom. Any movement there will rattle. Heck, check ALL your heatshields :) They like to come loose and rattle. The bolts on my 05 had rusted all the way through by the time I got her. Replaced with PPE headers, so no worries now, as in, no heatshield!

Otherwise, uh... Do you have a Lidbone? Mine rattled for a while. Make sure all the coil pack screws are on tight. Maybe your power steering pump belt is loose :)
 

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Discussion Starter #3
yeah, its been going on for a week now and seems like it is getting progressively worse. Its one of those things you check for a quick fix initialy, then try to convince yourself that it might just 'go away'. We have had 42 straight days of 100+ weather and i drive my car everyday so i tried to convince myself that it was heat related and that when it cools down maybe it will fix itself. HA.

But yeah, thats not gonnna happen.

I dont know what else to check. I can hear it coming directly from the engine at those low RPM's. The car also seems to sputter just slightly at idle (but not enough for me to think it would die), it really has never done that before. I did a pretty extensive search for buzz noises before I posted and did check the shear panel, diffuser and heat sheild around the muffler and couldnt find anything. Finally had a friend keep it rev'd at 2000-2500 and sourced it directly within the engine itself.

I checked mounting bolts but they all seem tight. It literally sounds like it is coming from directly inside the engine.

Just hoping if someone had a similar problem they could provide some sort of insight as I am at a loss.
 

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Weird. Take the valve cover off and check for a wiped cam, but normally those don't make this kind of noise. The lift bolts are in that area, I wonder if one may be loose? You can get a new set for like 10 bucks at a toyota dealer. They need replacing at like 60k miles, but if one is loose, might as well replace them.

What about a broken belt tensioner? That is right around the same area on the side, I've heard of those going out as well.

Nothing says 'fun' like hunting down a rattle in 105 degree heat...
 

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Hi all, found this site by Googling for the above problem. I have the exact same buzz on an '06 111r Elise (15k miles). Has just started in the last 2 weeks. Wondering if the OP managed to get the noise fixed? (will send a PM too, as this is a pretty old thread).
 

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Hi all, found this site by Googling for the above problem. I have the exact same buzz on an '06 111r Elise (15k miles). Has just started in the last 2 weeks. Wondering if the OP managed to get the noise fixed? (will send a PM too, as this is a pretty old thread).
I had this problem and it was resolved by replacing the stock exhaust. Something inside was loose and behaved exactly as described.
 

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Thanks MoS for your tip.

Update to problem:

Dropped my car off at a local Lotus specialist this morning to diagnose, and have just heard back from them.

They say the noise is definitely coming from within the engine itself. They've already taken the top off, but found nothing that could be causing it so far.. (I mentioned the exhaust, but it's definitely not that according to them).

To further track it down they're going to have to strip the engine down, bit by bit, until they find the bit that's causing it = possibly 15 > 20 hours work at a cost of £1,000 ($1,500ish)...

I'm slightly worried if I do nothing about it, whatever it is could go on to cause more damage... But, I also don't want to spend £1,000 tracking down a buzz/rattle!...

Think I'll drop it at another Lotus dealer (or just a local garage I know that do things on the cheap) to see if they can diagnose / quote (much) cheaper.
 

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Is it a rattle or a clatter?
More of a rattle than a clatter. A "vibrating buzzing" noise describes it best though.

It only happens at pretty much exactly 2k revs, which I guess is the resonating frequency of whatever it is...

Imagine a bolt that is very slightly too small for the hole it's sunk into. If you rev the engine it will start vibrating, bashing very slightly against every part of the hole making a buzzing noise. If you rev less, then the bolt will stay still, and (somehow) if you rev more the noise also stops (perhaps it sticks to one side, or vibrates so fast that you can't hear it?.)...

Hard to describe!. I'll make an audio recording and stick on youtube when I get my car back tomorrow AM. (5.30pm here now).
 

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Update: Got my car back. Though, unable to make a recording of the sound, as it's now been fixed :)

I'm not massively mechanically minded, but hopefully the following makes sense, and may help someone else if they have the same problem :)

Before putting the cover back on the engine, the guy at the garage flushed the engine valves. He'd noticed a tapping noise when starting the car, that pointed to a possible blocked valve.

Anyway, all fixed!. Total cost: £50 ($75). Engine sounds better than it's ever sounded. Very happy :) And pretty glad I didn't agree to them stripping the whole engine down! :)
 

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I had a noise like the thread's original poster described. The RPM at which the loud, heavy buzz/vibration occurred varied a bit with temperature. It sounded like it was coming from the valve cover or right side of the engine, but I couldn't localize it by listening. I removed the valve cover, checked all my valve clearances and looked for problems there, such as wiped cam lobes (which, I was long overdue to check anyway). But, everthing there was fine. I even reproduced it with the serpintine belt off (in case it was a pully shaft bearing). (And, since the belt drives the water pump, I did that only for short periods of time with the electric recirculation pump hot wired to run the whole time.) I finally used a long wooden rod to press on various things while holding the RPM at the resonance RPM. I found the problem to be the exhaust manifold to exhaust pipe flange. When I pressed on the head of the right side bolt, the noise stopped. The flange bolts were tight, so I suspected that the gasket was getting worn, and was getting a buzz pulse every time a cylinder fired (the exhaust gas pulse was probably causing the flange to separate a bit, then the spring would slam it closed). The pounding of the flange apparently propagates up the exhaust manifold to the head to the valve cover, which acts like a speaker diaphram and makes the sound appear come from the top of the engine (the sound from the valve cover was louder than the sound at the flange).

I am replacing the flange gasket, bolts and springs this weekend. Hopefully that cures it.
 

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I would never do a flush, after reading day and night on carbibles.com:

Flush: cleans up but there is a risk of clogging at the narrowest point (god knows where that is..) which actually INCREASES the risk of malfunctions due to deposits...

I tend to believe this. No flush for me!




Sent from AutoGuide.com App
 

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