V8 inconsistent clatter

hello all,

there is an issue for the collective knowledge of this forum to handle

my truck is an M reg Disco I 300 V8 i 3.9 auto with 137K kms on the clock

for quite a while now (around five months) and ever since the first oil change since it ended up in my loving hands, I have noticed something peculiar. At first the block gave and inconsistent, ie non-rythmic, metallic clattery noise that has been increasing in frequency, though not really in loudness.

It is rather hard to locate and quite unlike rocker-lifter noise, that is more high-pitched in comparison.

The most interesting thing is that it does not appear to be doing it when cold (although I can clarly hear lifter clatter from time to time, that stops immmediately). The non-rythmic symptom starts after a full run of the motor and after I park it running, it starts after a little while.

Other than that the engine runs fine, it revs nicely, no other funky noises, no smoke, MOT'd succesfully recently and passed with flying colours. I have also been treating it with more than regular 10w/40 changes, plugs and lead are new and recently tried a shorter MAN oil filter just in case...no joy.

The interesting thing about that is it's inconsistency, it clatters non-rythmically and only when hot and my mech proposes that we do nothing about it, since it is probably not worth opening the block for something inconsistent and hard to locate (I might tend to agree with him as I fear that when we open it up we will end up having to change a cartload of stuff).

PS why would it non-rythmically clatter only when hot? Could it be a peripheral and if so?

heeeeelp

could it not be a very fine exhaust manifold leak,?

hi LR, I am the last one to rule anything out, especially in a landie (haha). anyhow, the sound is indeed metallic, like something metallic. But am willing to have that checked out, many many thanks!

the high heat temp is causing expansion of the metal parts. sounds like summat is getting/working a mite loose. prob get worse over time and then youll need to have a lookee.

i guess its summat where 2 dissimilar metals are in close contact. or should be.
summat like the little end? or any of the bearing surfaces?

edit.
try a wooden stick and use it like a stethoscope. maybe able to pinpoint the area better.
whilst the engine is running of course!

Not the heat shield on the exhaust manifold?
just a thought

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