Hey fellas,

Around 60-65mph, a resonant hum develops which goes away if you fall below about 60mph or climb above about 65mph. It goes away if you take the drive out.

Also, there's a certain position on the throttle which makes the engine sound like a bag of hammers, almost as if it's revving really high - though if you move the throttle ever so slightly away from that spot, it sounds fine.

On a side note, there's also a knocking coming from the front end. It almost sounds like a ball joint except it only when you brake or if you're setting off from first? Thing is, there's a new lower control arm on either side with new bushes and new balljoints, and whilst I was in there I replaced the anti-roll bar drop links. Could it be the tie rod ends as I've not replaced them and the noise only seemed to come about after I had the tracking done (which was completely off the guage).

Thanks guys!

Hi,

Re the "resonant hum" at 60-65mph, my 1998 1.9d estate had exactly the same thing for the first few years of it's life, dealer couldn't find any faults. The problem disappeared after it's first cambelt change !

Also get the change in engine sound occasionally, a sort of deep growl, never really worried about it and have now done 140,000 miles.

Regards,

Andy.

Cheers Andy,

Not too worried about it really, it's just a pain in the backside on the motorway xD

Cam belt was changed maybe not even 1000 miles ago. Just done a service with fully synth oil a fortnight ago too.

Kinda sounds like a bad wheel bearing does, but surely, that'd be there all the time at speed, and the rear ones are brand spankin.

The hum could be a whole number of things, tyres, exhaust system, wheel bearing, etc etc.. Don't assume that because the rear wheel bearings are new that they are kosher, changed both of my rear bearings last mot and the passenger side one is noisy again already.

without hearing the 'bag of spanners' sound it's hard to diagnose, but the injection pump on these is a very raw and simple mechanical thing with no fancy electrics, could be anything like a dodgy or failing injector or a blocked fuel filter.. Does it only happen under very heavy load like going up a hill?

the knocking sound is almost certainly the front suspension top mounts, fairly common to fail, I change mine every time I change the oil normally get a single knock on full lock when I reverse out the driveway first thing in the morning!! either that or the rear engine mounting is getting tired seeing as you mention braking this could be when the weight of the engine shifts forward making a clonk.

I'd go with Tom's top mount suggestion from what you say - they are weak and have play in them for a pastime.

As for the hum, what tyres do you have on it? In my experience of Felicias the rear bearings can cause issues and are tricky to adjust perfectly - again as Tom says, just 'cos they're new doesn't mean they're OK.

Edited 14 April, 201214 yr by djaychela

Thanks fellas.

Theres two brand new continentals on the front, standard size. Complete exhaust is new-ish, all brand new exhaust mounts. The hum at 60 was there before and after new rear wheel bearings.

That 'bag of hammers' sound seems to occur when the throttle is in a certain position, regardless of where in the rev range. As if there's kind of a 'sweet spot' on the throttle.

Fuel filter is new also. No idea about the state of the injector pump or injectors, but I wouldn't be surprised if they were tiring. Its not easy to describe, but I suppose it just gets really clattery, then suddenly it goes to being a normal smooth engine once you either retard or open the throttle a tad.

Also, I'll replace the top mounts as it's probably unlikely they've ever been changed and judging by the horrendous state of the wishbone when it was took off, I suppose I'll change em out.