Noise like siren when stopping

[71Westy]

Here's an odd one - a new noise from the van.

When coming to a halt, I sometimes (it seems to happen in batches) hear a police-car like wail JUST before stopping. High in pitch to low. Then on starting it briefly sounds the other way. I'm only talking of during the last foot of travel, so only for about a second or so.

I've tried with the engine in gear but foot on the clutch, out of gear with the foot on the clutch, out of gear and no clutch, with brake and without brake, and it can happen in all of those situations. And then it goes for a while without happening at all.

All very odd - and thoughts? Sounds like it's the back of the bus, but it's hard to tell.

Nick

 

[Killaybay]

Happens to me too, and I would like an answer to this puzzle as well.

 

[jonboylaw]

Erm, always with the engine on right ? just as you turn it off or only when moving to a standstill with the engine on?
I would check to make sure there is nothing in the cooling fan intake and also that your Dynamo strap is on tight. Next check the fan belt is the correct tightness...

 

[71Westy]

Engine running all the time. Not tried it with it off. It's not when I switch the engine off....

 

[71Westy]

No thoughts anyone?

 

[jonboylaw]

Have you got a Turbo fitted ?

Just for clarity:
Does it do it when the van is stationary and you rev the engine?
If it only does it when moving, does it do it when you are coasting with the engine on tick over or even turned off?

Any chance of a video to help out here ?

I would certainly check the inlet to the cooling fan to see if there is something rubbing, then check the belt and pulleys, finally check the dynamo/alternator.

Edit, re reading this again, when it doe it again, can you carefully check the rear drums when it next happens, see if they are hot (be careful not to burn yourself).. could be binding drums, but it is difficult to diagnose with out a video or more detailed description.

I am sure someone will be along soon with a better theory..

 

[71Westy]

Well, had a good look for this and tracked it down to the offisde rear wheel. It sounds like a rubber component is un-lubricated (ooer). And it seems to be from the outer CV joint. But it could possibly be the wheel bearing? It only happens if I rotate the wheel slowly, and not when I rotate it quickly. I did this with the drum off, so it isn't the brakes.

Any thoughts?

Nick

 

[ZedBed]

CV's bang, bearings whine.

 

[Tankpants]

I have just started to notice this noise too. Not had a chance to look into it yet but it's a quiet whine, like a quiet siren as I slow down to stop.