This is probably an utterly dumb question, but could fellow backroomers enlighten me on the following.
I've had some rattle coming from underneath the car for some time, only happens at around 1000 rpm. When doing MOT (at the dealer's) I asked them to have a look. They diagnosed it as front pipe heat shield corrosion. They also said I could just use hose clamp to fix it.
Now, I had a poke around the exhaust pipe under the car. If I understand currectly, the heat shield in question is two half pipes that surround the exhaust pipe. If I slightly knock the shield with my hand or a spanner I can hear something vibrate with somme kind of rattle. However, these half pipes are actuaslly held with two clamps, and I don't see where it could be welded, thus, can't see possibly broken welds. So, I'm a bit lost. Maybe I'm looking at completely wrong thing ?
P.S. Cat is fine, and it doesn't rattle when knocking it slightly.
Thanks in advance
Kostic
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The heat shield will be a piece of metal, essentially a plate, which is between the exhaust and something which may be damaged by heat - typically somewhere against the back bulkhead of the engine bay.
They are frequently found to the front of the exhaust where it tends to be at its hottest or around the cat itself.
Now, whether or not you are looking at the heat shield on your car or not, I would have no idea - but does it look like its in between something hot and something vulnerable ?
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These heat shields always rattle on Primeras. Just bend it against the pipe slightly at one end and that should stop it.
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The heat shield will be a piece of metal, essentially a
plate, which is between the exhaust and something which may be
damaged by heat - typically somewhere against the back bulkhead of
the engine bay
Right, then it is rather a plate then a tubuluar structure. So, how could it then possibly be fixed with a hose clamp, that was suggested ?
P.S. It seems I was looking at the wrong thing. I looked at two half-pipes that kind of insulate the exhaust pipe, like an all around cover for the pipe.
Thanks
Kostic
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Your looking at the right thing. The heatshield is thin sheet metal, formed to fit around the pipe. To stop it rattling you could get a big Jubilee clip and put it round the heat shield where it meets the pipe (at its end) and tighten the clip. This will help stop it rattling. I also find that just bending the heat shield a bit, or knocking a dent in it, will change its stiffness and stop it rattling. They generally resonate at one particular frequency (i.e. a specific RPM).
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To stop it rattling you could get a big Jubilee clip and put it round the heat shield where it meets the pipe (at its end) and tighten the clip
Thanks, Aprilla
What actually confused (and still is confusing) me is the fact that the shield is held by a clamp as a stock fitment at that end. So, there is already a clamp at that particular place. Do I just replace it with a tighter one or put another one next to it ?
Thanks again
Kostic
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Yes, there is already a clamp. You have to tap it and see where its rattling - then try and clamp it there somehow. There is no particular science to this - just play about with it to stop it rattling.
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Aprilla,
Thanks for your advice. I'll try it when I get a chance.
Kostic
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