I have a 91 Miata with 30k on it. I hear a semi hi-frequency rattle
coming from under the car near the clutch/trans area when the car is reved
to around 4k. The rattle is not constant. While revving, the rattle is
only audible for less than a second, but is heard everytime I accelerate
past the 4k range.
Any ideas?
Thanks,
don
In article <4pk1h0$…@newsbf02.news.aol.com>, vv…@aol.com (Vvdag) wrote:
>I have a 91 Miata with 30k on it. I hear a semi hi-frequency rattle
>coming from under the car near the clutch/trans area when the car is reved
>to around 4k. The rattle is not constant. While revving, the rattle is
>only audible for less than a second, but is heard everytime I accelerate
>past the 4k range.
>Any ideas?
>Thanks,
>don
Does it do it with the clutch pushed in?? If not, then throw some lithium
based grease on the linkage where the slave cylinder touches the actuator arm
for the clutch. This seems to develop a rattle/buzz for some reason. If you
crawl under the car and have somebody push in the clutch a couple of times,
you’ll see what I’m talking about. There’s some info on this at miata.net
under the garage/squeaks&rattles section.
Good luck!
Mark
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Mark Juliano email: mark.juli…@gtri.gatech.edu
Georgia Tech Research Institute
7220 Richardson Road Telephone:(770)528-7881
Smyrna, Georgia 30080 Fax:(770)528-7083
My opinions are my own, mostly cause nobody else want’s em!
This sounds like the dreaded but fairly commom heat shield rattle. If
you can get the car up on a lift, get under there and stick a
flashlight and your hand up where the header joins the pipe that runs
between it and the front of the catalytic converter. That’s the "A
pipe", and it’s the heat shield at the very front end of that which
usually pops a weld and begins to rattle against the pipe itself,
making your car at 4000 rpm or so sound a lot like a garden rake being
dragged over concrete. If you’re lucky, you’ll be able to get your
fingers in there, find the broken weld, pull the heat shield away a
little bit, let it go, and make it rattle to confirm the problem. That
isn’t the only location where there are exhaust system heat shields,
so if that one isn’t it, be sure to check the others, including the
plates that screw down above the cat con. Those screws will sometimes
work loose as well.
If you find the A pipe one to be the problem, though, and you’re out
of warranty (a new A pipe is almost 200 bucks!), get yourself a
properly-sized hose clamp (probably soemwhere around 2 inches) and
clamp the end of the heat shield tight against the pipe. That should
fix it for about a buck or two.
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Voodoo Bob
’91 French racing blue A
Team Voodoo Proprietor
San Diego Miata Club Membership Houngan
Age & Treachery Racing, Ltd. – SoCal Region
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