30 replies to this topic

[The Otter]

Hi folks

I was driving on the motorway the other day, when I heard quite a loud bang, loud enough for me to pull over and check nothing had fallen off the car, but it was fine from the outside. Shortly after this happened (possibly coincidence, you never know...) a light grinding noise and a light whirring noise started coming from the engine/gearbox/drivetrain, but I was a long way from home and I've driven about 200 miles since this started. In that time, the grinding noise has stayed the same from what I can tell, but the whirring noise has definitely been getting louder and louder, and it's sort of rhythmical if that makes sense, as in the sound "pulses" every second or two and changes in pitch with how fast the car is going.

The noise is related to road speed, it stays exactly the same if I put the car in neutral or coast along in 4th with the clutch in.

Also, along with this issue, I've had a light knocking noise for a while that's been very intermittent, when you either get on or off the power, but now that knocking noise can be done on command. Every time you accelerate and every time you get off the power it knocks, from the drivers side I think. I know you'd all suggest engine steadies for this but the engine is completely solid, the bushes are fine and you can rock the whole car by grabbing the engine and it doesn't budge. It could be engine mounts, as I haven't checked those in a while and I've not changed them in my 2 and half years of ownership, so they could have perished. This would be a big coincidence though, that the knocking has gotten worse just as this whirring noise came about, so I'm thinking these two things are related.

The car has had brand new wheel bearings and outer CV joints within the past year and half, so unlikely to be them but still possible, however the whirring really sounds like it's coming more from the middle of the car (engine bay) than the wheels.

Does this sound like anything familiar to any of you? Perhaps an inner cv joint failure? I'm really hoping it's nothing internal obviously, but maybe something to do with the diff/gearbox? The engine (1992, City E 998) is on about 105,000 miles, so any original parts will have had a lot of wear and tear by now.

Any advice would be greatly appreciated.

Cheers

The Otter

[oltonlad]

wheel bearings??......are you running wide wheels as wheel bearings really dont like wide and/or 13" wheels.

[Treacle91]

i have the exact same problem with the knocking noise when the power is on and taken off...i'm just hoping it's not a thrust bearing:(

[oltonlad]

i have the exact same problem with the knocking noise when the power is on and taken off...i'm just hoping it's not a thrust bearing:(

if you have an lcb fitted then its probably hitting the floor on decelleration

[The Otter]

I was running 6x10 Wellers until two months ago when I switched to 3.5x10 steelies, but they are Timken bearings and only installed a year and a half ago. I do drive enthusiastically most of the time as well, so it could be bearings...

To be honest, I'm really hoping it is a wheel bearing, that's the easiest thing to fix if it has gone pop!

[Treacle91]

i have the exact same problem with the knocking noise when the power is on and taken off...i'm just hoping it's not a thrust bearing:(

if you have an lcb fitted then its probably hitting the floor on decelleration

Its definatly not that...as i dont have one fitted... it's something i cant pin point though

[Treacle91]

I was running 6x10 Wellers until two months ago when I switched to 3.5x10 steelies, but they are Timken bearings and only installed a year and a half ago. I do drive enthusiastically most of the time as well, so it could be bearings...

To be honest, I'm really hoping it is a wheel bearing, that's the easiest thing to fix if it has gone pop!

Wouldn't hurt to give them a check!

[jaydee]

Wheel bearings gone...

Jack up the car and rotate the wheels, checking for noise/play.

[Archa]

I had a knocking noise coming from my passenger side, it would stop knocking if I braked and sometimes if I accelerated and when i turned right, I found out the castle nut was loose so tightened it up and put a new pin through it, the knocking noise stopped, check the castle nuts as this is very easy to do. :) as for the other noise I have no idea sorry.

[The Otter]

I'll be giving it a good going over tomorrow, fingers crossed it's a wheel bearing but they were all tight as a drum only a week ago, and like I said it sounds more like it's from the centre of the car. Still, I'll get the obvious stuff checked over first.

If it were something like an inner CV or something in the gearbox/diff, would it more likely have just lost all drive? Or is it still possible that something in there has just gotten excessively worn to cause these symptoms? Remembering it's quite a high mileage engine, if that makes any difference.

[tiger99]

I strongly suspect that the diff is failing, as your hub bearings and CVs are not very old. You can sometimes tell by being able to move the pot joints in and out by hand, but check that the drive shafts are not capable of much sideways movement in the pots, as they could be failing. A failed pot joint is actually not very common, but not impossible.

[ianclark1275]

a quick diff check is jack front up both wheels clear
in gear
then turn one wheel by hand
the other should spin in opposite direction

you can also narrow down the "sound" as the actual diff wont be moving, as it is when driving...

IC

[tiger99]

I don't think that diff check will work, as he still seems to have drive, so the wheel most certainly will spin in the opposite direction. But it may reveal some strange sounds.

[Gulfclubby]

Just to share an experience here: I had a similar case, loud bang and nothing seemed wrong. Turned out my lower shock absorber bolt on the passenger side (LHD car) had snapped off and the shock absorber (which was the wrong type, too long, hence the stress on the bolt (factory packaging error and me dork not checking for correct size)) was just dangling in the air after that. I drove about 200km before I noticed the problem and then only because the shock absorber had sheared a hole into the braided steel brake hose, as it had been obstructing it. Losing braking pressure on a turn is not cool.

Suggest you jack the car up on the front subframe, support it with axle stands and give it a very thorough inspection for unwanted play, fouling and missing/broken parts. Don't forget to check the insides of the wheel arches too.

[The Otter]

Had time for a quick check this morning, its definitely not wheel bearings, there's no play in anything wheel wise. I'll give the drive shafts and pot joints a check for any play later.

Let's hope its a pot joint...