Buzz from behind Dash

Mactype · Postby **Mactype** » Thu Oct 04, 2007 12:00 pm

Before I go nuts and start ripping out the dash I figured I'd ask the experts.

I've a high pitch sound that seems to be coming from behind the dash. it happens when accelerating or when cruising at a certain rev range - appears to be around the 3000rpm mark.

When it happens you can either back off or drive through it and it stops. I can also make it happen when cruising by pushing down on the accelerator pedal to a certain point - again leave the pedal at that point and it continues, back off or push down further and it stops.

Any ideas??

Juffa · Postby **Juffa** » Thu Oct 04, 2007 12:10 pm

On the earlier MX-5s there was a problem with a spot weld on the exhaust heat shield. The weld breaks and at certain rev ranges it vibrates. Have a look at section of exhaust between the header and the cat. The dodgy spot weld is at the header end. Some people put a metal hose clamp of the heat shield to stop the vibration. Others pull the heat shield away from the exhaust so it can't hit it, or in my case I installed after market extractors, which replaces that whole section of exhaust.

J

Garry · Postby **Garry** » Thu Oct 04, 2007 12:48 pm

If you have an early NA you might find that the rubber gromets where the alloy heater pipes run through the firewall have worn through. You can try cable tying the pipes together to see if this changes the noise but if it's coming from there the only way to fix it properly is to replace the rubber gromets.

Mactype · Postby **Mactype** » Thu Oct 04, 2007 1:45 pm

Thanks guys, its a NA8 clubman but I'll check over your suggestions.

It does sounds a bit more like an alarm going off or something though. Its got an aftermarket alarm fitted and I was wondering if it was electrical interference or something. Damn annoying!