Gregmeister said:
Once you have replaced part #7 and all the other chain guides and tensioners, as would be the done thing to do, please could you report back to the thread and let us know if this has indeed solved your problem.
Mine does it too. Has done for ages, and from my research into the subject, the overwhelming general consensus, Land Rover forums included, is that it is valve train noise due to oil starvation on initial startup (vanos possibly included). Which I have always gone with, because to me, it sounds like valve train, not timing chain/ chain guide issues. It only lasts momentarily, which does not add up if it was chain guide, or chain tension issues, as this would manifest itself as a constant rattle. But Maybe I am wrong. Maybe Fordkoppie can elaborate on how this part causes the noise? Would be most helpful, because I cannot find a similair prognosis online.
There has always been a fair bit of debate around the longevity of the timing guides and replacing tensioners on these motors. If your car has 250k+ maybe it is a good precautionary step to take regardless. It won't be cheap to do, unless you can do it yourself, but surely better than replacing a motor.
Without hearing the noise myself, I cannot say for certain that it is the chain. But at the sort of mileage he is at, he is running on borrowed time. So as you said, its a good precautionary step to take.
Regarding the sound itself - I have heard a few that was in fact the worn out chain/tensioner components. And it also takes just a few seconds to silence after a startup.
The thing is, the chain tensioner works with oil pressure. Therefore, the engine needs to run first, before it can actually tension the chain fully. That would be the function of part #20. It has an internal spring as well, but not nearly stiff enough to keep the chain properly tensioned without the oil pressure.
So what happens is the following:
Part #7, #17 and the chain itself wears out. naturally there is more slack in the chain, so part #20 needs to extend much further to tension everything up.
So when it is standing overnight, the pressure bleeds off part #20, and now relies only on the internal spring. But because the piston needs to extend much further than usual, the spring is exceptionally weak at this point (Spring tension = Deflection x stiffness constant). So it rattles until the oil pressure is up.
If you switch off the car after it has quietened down, and restart within a short time, it will be quiet on the next startup, because the pressure has not bled off from the tensioner.
Greg - Your car has Vanos as well, so that is yet another thing that can rattle until oil pressure is up.
With #7 being plastic and 20 years old, and worn thin, it doesn't like this chain slapping against it with the chain being slack at startup, until one day it simply collapses. And then you wallet also collapses:blueCry:
Hope this makes sense
VukMiler said:
The thing is, is it something I can do at home
Biggest problem would be to time the cams again, because I assume you might not have the alignment tools?