300tdi bottom pulley/crank pulley squeal

Hi guys,

A couple of months ago when I last went off-roading, on the way home my Disco developed a squeal from under the bonnet - i didn't think anything of it and thought i'd just have to replace a bearing or something.

Many weeks pass, and I keep forgetting that it makes this horrible squealing noise - because it doesn't do it straight away, it takes 5 minutes or so before it starts doing it - makes me jump every time.

Here is a video of the noise -



So it goes up and down with revs, does it whether the aux belt is on or off. The bottom pulley is not loose - atleast I can't get any play in it by hand. If I rev high and let the revs drop it will stop for a brief period - 5 to 10 seconds. If I spray a bit of wd40 behind the pulley it stops for a while and intermittently make a noise.

I understand that the bottom pulley is just bolted to the crank without any bearing, or am I wrong? Is the bottom pulley rubber bonded?

I'm not sure how the troubleshoot this further, or what could be the cause?

Thanks,
Foz

Could be the timing belt idler or tensioner on the way out (when was it last changed?). If it is and the bearing fails then you end up with bent pushrods and potential valve gear damage. Worth a look in the very near future!

as above or the outer timing case seal

The timing belt (and idler/tensior) were done in July last year - so hopefully they are still OK and haven't failed early.

James, would that be the seal that sits just behind the pulley (in the timing case)? May sound obvious, but I like to be sure.

Thanks

fozt said:

The timing belt (and idler/tensior) were done in July last year - so hopefully they are still OK and haven't failed early.

James, would that be the seal that sits just behind the pulley (in the timing case)? May sound obvious, but I like to be sure.

Thanks

Click to expand...

yes

fozt said:

The timing belt (and idler/tensior) were done in July last year - so hopefully they are still OK and haven't failed early.

Thanks

Click to expand...

Who did the belt job as the tension value has been amended from 15Nm down to 11 IIRC. Excessive belt tension wont help although it would have to be over by a lot to cause premature wear, that said, if it is over-tensioned then the belt could be riding off one side of the pulleys and may be wearing against the casings. Have a look up the timing cover wading hole, if there is a lot of black 'fluff' in there then it is a sign the belt is fraying.

Hi @fozt


When you went off road did you have wading plugs fitted?

Cheers

@Kwakerman - my dad did it, he's a mechanic however I don't know what tension he would have used. I will get him to check. I've done less than 300 miles since the new belt was fitted, though. I'll take a look tomorrow in the day, i've had a belt rip itself to shreds on me before so know about the black stuff you're referring to!

@neilly - I didn't mate, completely forgot. What a noob, aye?

Foz

@fozt

OK, when you went off road, did you get it deep and dirty ?

Cheers

@neilly

It was definitely dirty, but I don't remember it being overly deep - it wasn't over my bumpers.

What are you thinking?

Foz

I think he may be thinking the same as me in that water got in to the belt / bearings due to lack of a wading plug in the timing case (there are two, one for the bell housing / clutch and the other for the timing case). That said I'm now thinking of a nice burger and chips for my tea!

Kwakerman said:

I think he may be thinking the same as me in that water got in to the belt / bearings due to lack of a wading plug in the timing case (there are two, one for the bell housing / clutch and the other for the timing case). That said I'm now thinking of a nice burger and chips for my tea!

Click to expand...

You were thinking the same, but then I thought about a nice glass of white wine and a baked tattie with tuna , mayo and lashings of virgin olive oil with tomatoes on the side.........................................I think the burger and chips would have been better.........

Cheers

STOP talkin about FOOD yu makin me HUUUUUNGRY ! Mmmm wots for tea

Kwakerman said:

I think he may be thinking the same as me in that water got in to the belt / bearings due to lack of a wading plug in the timing case (there are two, one for the bell housing / clutch and the other for the timing case). That said I'm now thinking of a nice burger and chips for my tea!

Click to expand...

My policy, I never take the wading plugs out except when my Disco is on the hoist for servicing, to check for leaks, they stay in whenever driving, because...........you just never know where that next deep and dirty mud hole is going to be,and I don't want to have to stop and put 'em in.