Lotus Elan

Help Identify This Strange Noise Please

PostPost by: Stevie-Heathie » Fri Nov 10, 2017 6:57 pm

My S3 started to make a chinkachinkachinka type rattling noise on the drive home tonight.

It?s intermittent (of course!) but before I jack her up and start ferreting around I thought I?d see if the collective wisdom of the forum had any ideas.

45 second video with sound attached.

It seems to be something towards the bottom of the engine bay, I don?t think it?s from within the engine itself.

https://youtu.be/z4ctx7M02xE

Thanks in advance all

Best
Steve
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PostPost by: Concrete-crusher » Fri Nov 10, 2017 7:09 pm

I had a similar noise that turned out to be the solid 2 bladed fan ratting at the joint. However if you don't have the mechanical type fan , then maybe check the timing chain tension ?

Regards Steve
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PostPost by: Stevie-Heathie » Fri Nov 10, 2017 8:00 pm

Thanks.

No mechanical fan so that?s out.

Hope it?s not timing chain because the head was re-worked just a few months ago. Also, it?s intermittent so that would rule the the timing chain out?

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Steve
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PostPost by: nmauduit » Fri Nov 10, 2017 8:08 pm

any chance that the oil dip stick may contact the alternator pulley/fan ?
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PostPost by: 1owner69Elan » Fri Nov 10, 2017 8:40 pm

Doesn't sound like the timing chain to me. Especially from the video/sound taken from the top.

Besides dip-stick, how about alternator/generator bracket/mounting?
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PostPost by: 1owner69Elan » Fri Nov 10, 2017 8:45 pm

I also had the mounting plate on a high torque starter become loose and rattle.
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PostPost by: Stevie-Heathie » Fri Nov 10, 2017 9:10 pm

Thanks all. I?ll check dipstick, Dynamo and belt, and starter tomorrow.

Any more suggestions, folks. I do like the idea of it being a loose ancillary.

My darkest fear is water pump, but presumably that?s more of a silent killer?

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Steve
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PostPost by: el-saturn » Fri Nov 10, 2017 9:37 pm

.......my engine also sounds "sluggy" at idle and cold HOWEVER if we could of heard the same engine hot and at idle it'd be easier to make a diagnosis!! sandy ------------------------- goin ta bed! PS my engine starts imediatelly and after a mile of slugginess everythings' back in the green! lets hear her at various stages of WORK (high revs hot, leaving home early in the morning, getting layed back in 1hr hr of traffic and still 90? C water temp. whereafter some of us'll may detect the problem. sandy: just a mediocre TC scientist!
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PostPost by: Stevie-Heathie » Fri Nov 10, 2017 11:27 pm

Thanks Sandy

Confirm the video was taken with hot engine, after a 45 minute drive.

Best
Steve
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PostPost by: 2cams70 » Fri Nov 10, 2017 11:32 pm

Check the clutch release bearing / fork. Does the sound change with pressure on the clutch pedal?. Also check noise with clutch disengaged and car in gear, clutch engaged transmission in neutral to see if there is any difference.
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PostPost by: MarkDa » Fri Nov 10, 2017 11:50 pm

A new timing chain can ease off and rattle at tickover - tends to disappear if revved up a bit.
Not a big problem to sort just take out slack until noise goes.
Could be chatter on release bearing which would probably go with pressure - possibly even manually under car if single handed.
Last edited by MarkDa on Sat Nov 11, 2017 7:02 am, edited 1 time in total.
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PostPost by: seniorchristo » Sat Nov 11, 2017 1:24 am

Stevie
Do I hear an exhaust leak? :)
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PostPost by: diablo » Sat Nov 11, 2017 8:27 am

Have you try to use a sth?toscope to get better indication of the location of this noise ? A very usefull tool for chasing the mecchanical noises .
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PostPost by: Stevie-Heathie » Sat Nov 11, 2017 5:58 pm

RESOLVED!

The two bolts that secure the exhaust to the bracket on the gearbox had parted company with the rest of the car. So at idle the exhaust was knocking against the bottom / side of the gear box.

An easy fix :-)

Thanks all for your help. Love this forum.

Best
Steve
Attachments
c89780e7-3f21-4864-a3f8-e6572206e218.jpeg and
Supposed to be two bolts in there!
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PostPost by: MarkDa » Sat Nov 11, 2017 7:04 pm

Simples!
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