2005 Mazda3 2.3 drivetrain clunking -- bad engine mount?
 

Hi folks,

I have a 2005 Mazda3 with the 2.3 liter engine and five-speed. I have about 57,740 miles, mostly city.

For months now, I've had an annoying clunking/clanking from the front passenger side -- usually when engaging the clutch, but occasionally over a one-wheel bump even with the clutch fully engaged. Starting from rest and engaging the clutch will produce a series of CLANK-CLANK-CLANK sounds from the vicinity of the transaxle. It's worst when the car is cold and tends to lessen, though not disappear, when everything is thoroughly warmed up. Sometimes, starting the engine will also produce a single CLUNK. A patch of rough pavement will also sometimes elicit rattles from that area.

Anyone have any thoughts about possible causes? Although the noise accompanies clutch engagement/disengagement, the clutch isn't slipping. My first thought was the clutch release bearing, but while that might rattle, I don't know about it causing all this clanking, and it doesn't seem like the throwout bearing would be temperature-sensitive.

The possibility I was considering today was a bad engine mount. Do these symptoms seem consistent with a failed (or failing) mount? Are there other possibilities I'm not seeing?

Thanks!

Left or right hand drive (so we know what the implications of the "passenger's side" might be)? This is an international forum.

Oops, good point. This is a U.S. left-hand-drive sedan, so when I say "passenger side," I mean the right-hand side, away from the driver.

I ended up replacing the engine mounts. Sure enough, the right-side mount was broken internally. There was no external indication that there was anything wrong with it, but when removed, it was clearly broken; just picking it up, you could hear the familiar CLANK.

This was a lot more expensive than I was hoping, but it's made a real difference in drivetrain feel and ride. No more clank and thunk on clutch engagement, shift engagement is crisper, and the front end feels much more of a piece over rough pavement.