Chirp chirp chirp goes the landy (but it's not a belt...)

Feb 28, 2010 21 Replies

The Landy (Defender 110, Range Rover 3.9 V8, LT85) has been chirping occasionally for a few months, recently it's become continuous and louder - it's driving me round the bend and as we're 3 weeks away from driving to Italy, it's a bit of a worry that something's going to fail. I was pretty sure it was either a belt or the water pump/ alternator/PAS pump bearing, but I ran the engine with all 3 belts removed yesterday and it still did it :-( The chirps keep time with engine speed, not road speed & still happens when we're stationary so I don't think it's from the gearbox or transmission. When it was more occasional it seemed to happen once the engine was warm, but now it's all the time.



Digging around the web, I found two possibilities - a tappet on it's way out (they are Britpart from before I knew better and I've always thought one was a bit noisy) or a mounting rubber (this from a Harley Davidson forum!). I'm also wondering about the clutch release bearing, although depressing the clutch makes no difference, which I'd expect it to do so if it was the clutch release bearing.



Any other ideas?



TIA,



AndyC.


Serpentine auxiliary belt, or tensioner bearing?

Can you be any more specific as to where the noise source is?

Chirp? Light/heavy, high/low pitch, frequency same/lower than engine speed ???

A tappet failing will show itself as increased rocker clearance and if it fails completely you will know about it! Use a long sounding stick to eliminate this one.

Gearbox input/constant motion bearings are more likely to 'rumble' - sounding stick again.

Exhaust/exhaust manifold leak? Head gasket leak?

A guard/shield/cable/linkage vibrating against something? (unlikely to be temperature-dependant, though)

Sadly not - pre-serpentine engine, but I took all the belts off and ran the engine (so no alternator, PAS pump or water pump turning) and it still did it.

AC.

It's a tricky one to track down. It does sound more like the engine area than the gearbox, but I know from experience that noises can be tricky to pin-point where they're coming from.

Chirping like a bird! Quite light, medium pitch, keeps time with engine revs but at a lower rate - i.e. like something being driven at

1/2 or 1/3 engine speed, which is what made me think it was something belt driven.

I think that's my next area to investigate, but hard to get to...

Gearbox rumbles, but it's an LT85, so that's normal ;-)

Don't think so, it's not a blowing sound.

Don't think so, it's too regular.

I'm going to see if there's some way I can record the sound and post it on the web.

AC.

Oil flow to rocker arms. I've seen rocker shafts assembled incorrectly and it causes this - the flow increases but not at the point of loading, leading to a chirp or squeak noise each time that rocker arm moves i.e. once every 2 revolutions, normally quietening down with an increase in rpm. Depending on the source of the rocker shafts, they are normally marked or notched to indicate fitment position, check any haynes book of lies that has a rover v8 engine for more info. Badger.

I was going to suggest the viscious coupling on the fan but how that could be without any belts is a bit of a challenge. Not a lot else you've not covered. Distributor/Oil pump? Air leak?

Had that on my Disc TDI 300

A new tensioner and bearing for the serpentine belt cured it

DieSea

One would expect that to be a chuff but if the hole happens to be the right shape (like blowing over a bottle) or has a loose bit of summat (to act as a reed) it could conceivably chirp.

(unlikely to

And likely to have a resonance, ie. it will be really bad at a particular engine speed and drop off either side.

How about a squeaky belt, pully muck or damage? Oh, no, you said you took them all off, all but the timing belt I bet though. B-) Does it have a belt or good ole reliable chain?

Check your exhaust manifold gaskets/bolts. Especially at the rear cylinders. If they work loose they chirp every second rev. Don't keep tightening them, I did and stripped out the threads. Get some genuine LR gaskets if it turns out to be the problem and torque them up to factory specs.

Charles D Dalrymple

Aha - that sounds feasible. In fact now that you mention that I can vaguely remember when the external oil feed banjo on the 2.25 in my lightweight came loose and the rocker shaft ran dry it made a similar noise, but that was 15 years ago. I shall have the rocker covers off over lunch and take a gander - bit of a worry if I've put one in the wrong way around but at least it would explain the noise.

Cheers,

AndyC.

Dizzy could be the problem but I'm hoping Badger's got it with the rocker shaft - cheaper fix!

AC.

It's a pre-serp V8 and it still does it with no belts fitted :-(

'tis a good, not very old, chain. I'm hoping Badger's rocker shaft suggestion is the right one - seems possible.

AC.

Did them + the manifolds are held on with studs, brass nuts and genuine gaskets, so should be OK.

AC.

The brass bloody nuts will come loose - as they always do, so it's worth checking them.

I had the same on a 2 1/4 petrol on my 2a once, turned out to be the dizzy, all it needed was a smear of grease on the "cam" that operated the points.

Now I guess the 3.9 doesn't have points.. but still I thought I'd throw in that thought.

Andrew

I've yet to have a V8 which didn't develop a blow on the manifold to downpipe. Dammed annoying.

My VM had a chirping head gasket prior to a rebuild (2nd!).

Get yourself down to (insert supplier of choice here) and get a stethascope. Ideal for tracking down this kind of stuff. Goes without saying to beware of moving parts when checking (just incase anyone else reading tries to sue my ass!).

Lee D

(Almost) spot-on! Dodgy rocker on number 5 exhaust valve - the oil-way had never been drilled all the way through on the rocker, so the push-rod/rocker interface was dry and looking pretty unhappy.

I'll need to get a new rocker and push-rod but at least an easy fix. The rockers are solid steel ones, supposedly better than the ally originals, but I think I'll just get a genuine parts ally one as a replacement (apart from anything else, I can't remember where I got the steel ones from). Mixing and matching is probably not ideal but I doubt it will be an issue at the sort of revs I normally use.

Gory detials with pictures -

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AndyC.

Bit of a bummer

But at least it's sorted

Now I'm off to Buckley's in the morning

Got to pick some core plugs up for a TDI 200

DieSea

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