Strange noise at top of a hill ?

[smudger18]

After driving up hill and once at the top, in 4th gear, I ease off the accelerator and there is a strange noise, I think coming from engine/gearbox.

Has anybody else had this and if so, any clues as to what it might be?

[1071 S]

I think it was the blue paint flaking off the drive shafts




I tried to fight the urge to sarcasm....... but failed




Sorry

[mk1rally]

Transfer gears going off load or diff bearings?

[smudger18]

Transfer gears going off load or diff bearings?

Any way of checking these?

[1071 S]

Pleeeeaaase

I was serious - how on earth do you expect people to diagnose a "noise"?

A rattle, whine, scream, grumble, tinkle, patter, clatter what?????

I would expect a loose exhaust (worn engine mounts/steady bar) to bang on the body as you lift off .... worn diff bearings cause an irregular whine as power levels change, I would describe the noise caused by excessive idler clearance as a sort irregular clatter.... (but is only obvious in neutral/clutch out....)

If you need help - so do we.

Good luck, Ian

[smudger18]

Pleeeeaaase

I was serious - how on earth do you expect people to diagnose a "noise"?

A rattle, whine, scream, grumble, tinkle, patter, clatter what?????

I would expect a loose exhaust (worn engine mounts/steady bar) to bang on the body as you lift off .... worn diff bearings cause an irregular whine as power levels change, I would describe the noise caused by excessive idler clearance as a sort irregular clatter.... (but is only obvious in neutral/clutch out....)

If you need help - so do we.

Good luck, Ian

I wasn't expecting people to diagnose a noise without further info - now that would just confuse a stupid person wouldn't it?

It's a bit like the normal A-series noise when you ease off, only louder. My partner likened it to something on the fanbelt "clattering" or catching as it rotates, if that makes any sense? probably not. I have since checked fan and cowl and all looks OK. A little play on the fan, that's all.

As I said earlier, it never does under normal driving, just at the top of climbing a hill when revs have picked up.

Hope this helps, Ian,

[Matty]

If the noise increases/decreases with engine speed, and you say there is a little play in the fan, then I would guess it could possibly be the bearing in the water pump. Causing the fan to move slightly at higher speeds when its drawing more air in.

Is there any signs of rubbing on the fan blades?

[smudger18]

If the noise increases/decreases with engine speed, and you say there is a little play in the fan, then I would guess it could possibly be the bearing in the water pump. Causing the fan to move slightly at higher speeds when its drawing more air in.

Is there any signs of rubbing on the fan blades?

The noise insn't there, when accelerating, or at higher speeds. When almost at the top of a hill, and you are in 4th, when you ease off the ccelerator, still in gear, that's when the noise appears. After re-applying the accelerator, the noise disappears.

I can't see any signs of rubbing on the fan blades or the cowl?

[greyghost]

sound's like diff pin to me, as you ease off there is no load on them and they "can" rattle. or it could be anything in the drive-chain the most-likely cause other than diff would be gearbox bearings or transfer gears.

this would be my guess.

[smudger18]

Update - after taking it out for a good run last night, the noise is there when easing off at 50mph or more on the flat as well as uphill. But it doesn't do it downhill.....

[Tim]

Sounds like excessive diff backlash.

Tim

[smudger18]

Sounds serious Tim?

[AustinSuperSeven]

I was going to suggest engine mounts or top steady bushes worn so movement of engine rubbing the fan/housing but you say there is no sign of this...
sounds like gearbox internals then

[Tim]

If it is backlash in the diff or geartrain its potentially quite expensive. I think you need to find a Mini specialist that can diagnose it properly. You need to definitely rule out worn/inadequate engine mounts and steadys, they are much cheaper to repair or supplement if thats the problem. After that your options start to get expensive.

Tim