Technical Not so good vibrations from the rad fan

[vexorg]

A new one this weekend, my daughter saying her 500 was making a strange and bad sounding noise.

I'd have sworn the exhaust was touching the body, this loud resonating noise from under the handbrake area. But no, exhaust was miles away from the body at all points, even moving the tailpipe around.

Turns out that when the radiator fan goes on to high speed then that noise starts. You can barely hear it outside the car, and only a little in the engine bay.

Obviously hot day and aircon on all mean it's at high speed more often just now.
Bumper off to check what it was. So radiator itself felt a little loose in the top rubber mounts, not overly so just a bit easy to move back and forward. The fan mount on the gearbox side has a little movement in the clips, half a mm or so back and forth.
The fan itself feels secure, and no real movement or play in the bearing.

I packed out the radiator mounts to lock it in firmer to the rubber mounts, then forced a cable tie through the fan mount to rad body to stop any movement. That helped a little, but the noise is still noticeable.

The blades of the fan have weights on them, I'm wondering now if one has come off and it's lost balance. Either than it is the fan bearing and just cant feel it by hand.

It's done 50k miles in 8 years now, are the fans prone to failing (not read anything about that)

 

[jrkitching]

are the fans prone to failing

It's not common, but it's happened before.

I'd suggest not using the A/C until this has been fixed. This will significantly reduce the need for the fan to work at a higher speed.

Worst case scenario; the fan punctures the radiator, the driver doesn't notice and cooks the engine.

 

[Ralf S.]

I've not heard of fans failing.. they have a fairly hefty motor to spin up a fairly light blade.

My thought was the fan frame was tapping against the radiator, or the radiator was tapping against the radiator frame.. but if you've packed it all out so it's tight then that should have fixed any "slop" rattles.

Have you checked the air intake pipe that connects the airbox to the slam panel? On the 1.2 the intake pipe fits into a slot on the slam panel. It's held "tight" by a moulding that fits into a slot on the radiator or the radiator frame (I can't remember which) but the moulding is square and the intake pipe is round, so the two are glued together.

During air filter removal the pipe is awkward to remove from the slam panel, so the glued joint gets stressed and can separate. This would leave the intake pipe only held in place at the airbox and where it fits into the slam panel, which is a loose fit and can vibrate. Also the moulding is still there and the pipe can rattle against it. You can tie the lug on the intake pipe to the moulding with a cable tie to hold them together tight.


Ralf S.

 

[vexorg]

A few years ago there was a similar noise, and it was the fixing on the slam panel, that had the bolt on the top tightened up and cure the noise then.

In fact, I might take the intake pipe off altogether and try it.