ENGINE TAPPING THROUGH TO 3000 RPM

[Wag]

My 406 hdi 110 estate 2003 seems to have developed a tapping noise (high pitched) when accelerating. It disappears after about 3000 rpm.

If anyone has had the old cortina ohc engine, it's like that, but that was bearing issues prior to needle roller upgrades. Now showing many age!

One thought is the tappets, which I understand are hydraulic, could it be old or incorrect oil?

Not using any oil, 110k on the clock.

Advice would be appreciated.

[steve_earwig]

could it be old or incorrect oil?

Err, you don't know? If you don't know how old the oil is then it's probably due a change!

[Wag]

On reflection the oil has done less than 6k

[Doggy]

I seem to recall this being attributed to worn injectors back in the day. Bosch-equipped HDi 90 & 110 engines often made a rattling noise a bit like a petrol car 'pinking' under full power conditions.
Personally I always thought they were programmed to reduce or abandon pre and post injection at full power thus sounding more like a mechanical direct injection engine at those times

[PeterN]

As Doggy says, faulty injectors can cause this sort of noise but in 10 years of 406 ownership I never had one fail. Hydraulic tappets can make a similar noise if not operating correctly, if this is so an oil change might help.

Peter

[Wag]

Thanks guys. I'll look into it.

[Welly]

What about the bottom pulley for the aux belts?

These used to fail on HDi's and make a horrible ticking noise. Tell-tale signs are a brown coloured 'dust' or even bits of swarf around the area of the pulley. The noise develops when the vibration dampening mechanism fails inside the pulley.

[dirtydirtydiesel]

What fuel have you used recently?

My injectors were noticeably louder on Morrison's crap diesel & with Esso or Shell much quieter
even more so with 50ml of mineral 2 stroke oil in the fuel

[Wag]

I only use high st fuel, esso, BP etc.
What does the 2 stroke oil do?