Rattle from engine on hard acceleration

[adam03031980]

Hi all

I have a 406 HDI 110 and on hard acceleration between around 2000-3000 rpm there is a distinct rattle most would presume it is the crankshaft pulley however i had that replaced by peugeot about 12 months ago so what is it as it is starting to baffle me a little. the turbo seems to be fine as i can hear it whistle.

[mbell666]

Fanbelt tensioner?

[adam03031980]

I had this crankshaft pulley fitted 30/01/07 if it is that "again" what rights do i have in getting it replaced or am i liable for the full cost

[Welly]

Sorry fella but all HDi 110's do this.

It's a characteristic Diesel "clatter" around 2400 - 3000rpm but then promptly dissapears after 3000 rpm when the 3rd piston of the HP fuel pump delivers more fuel in the upper revs.

Basically the HDi lump runs very lean and borders on Diesel-like pinking most of the time, in other words there's only just enough fuel being burnt without it packing up all together

When the bottom pulley goes you will get a really loud smacking noise at ALL revs.

Take it over 3000 tomorrow and listen for the noise vanishing - you've nothing to worry about hear

Welly.

[steve_earwig]

Hey, are you saying this horrible loud rattle mine makes up 'til 3000rpm is something they all do? But I can hear it eching off buildings! It does it anything above idle though

[Welly]

Yes this has been on here before and we all concluded at the time that all our HDi's "clatter" - Ok my estimate of 2400 - 3000 may be a bit off but that's when it's most noticeable I think. Interestingly after a really good motorway run the noise reduces a bit

Funnily enough the Seat Leon on Holiday did the exact same thing (PD engine).

[steve_earwig]

Mine was going quiet when the engine was good and hot, now it doesn't seem to anymore (or is it paranoia's tuned my ears for it )

[Welly]

I think fuel quality may have some bearing on the noise

I'm still debating whether or not to slosh in 1litre of cheap engine oil (mixed with 5ltrs of Diesel) as recommended by that diagnostics forum I found.

Apparently it's the same sort of effect as feeding a cat some lovely cream

[muffindell]

I was told it was the second stage of the injectors that came in above 3000rpm, and that's why it goes quiet - more fuel i guess, a common noise on HDi's so a dealer told me

[eoin27]

They all make that noise at that rev range because thats when the turbo kicks in and pushes the engine harder. Now if your HDi is making the noise and its very intrusive (just like my last HDi) then it is probably down to the tappets. Getting these sorted out is pricey but will surely eliminate that bad noise. Worth doing if you're gonna hold on to the car. My new HDi is perfect mechanically and although I hear this noise it is not nearly as bad as the other one.

[steve_earwig]

Hi there. Seeing as how it was a bit quiet at 7 o-clock this morning I thought I'd put noise+hdi in a search engine and see what happened. Along with the usual "my crank pulley's exploding!" stuff I got this:
From here:

Its the injectors. Below 3200rpm these commonrail engines has what is known as pre-injection and above 3200rpm this is switched off (The fuel is delivered in one big lump). The common consensus seems to be worn injectors cause this noise, my local Peugeot tech tells me he is seeing more and more HDi's with these symptoms now.
Mine does it a small amount when the engine is cold, it gets quieter as the engine warms up. An Italian tune up or long motorway run seems to get rid of it completly for a few days.
All in all most of the older HDi's seem to do it, it hasnt harmed my engine yet so I dont think you have much to worry about really.

There were a few more in a similar vein, does it sound likely?

[Welly]

"Italian tune up"

I was aware of the pre-injection just before TDC- can't remember the benefits though

Mine rattles terribly but will quiten after a good run. I think it's a case of... if it aint broke don't fix it! unless you feel flush and want to replace the HP pump, rail an 4 x Piezo injectors

[steve_earwig]

HP pump, rail an 4 x Piezo injectors

Cheaper to buy another car...

If it's really down to the injectors then how can something so small make so much noise?? Maybe I can get my other half to ring up Pureć and see what they reckon (hmm, "yes madam, you really need 4 new injectors" )

[Longintooth]

Hi all
Common rail has been around for much longer in trucks and had very good form. The HDi is one of the first car applied examples. Some comments are implying that it is this that is responsible for a rattle. My Hdi 110 does not rattle anywhere in the rev range other than the usual diesel knock at idle (85,000 miles). The CR only disables the pump pressure at idle and should deliver full pressure anywhere above. The clever bit is the ability to deliver pre,mid and post injection phases - something engineers only dreamed of before electronics. The HDI should not make any diesel knock in normal driving and should be as quiet as a petrol from a fueling point of view. I have never heard any injectors rattle on any type but I suppose there is always a first. If the rattle increases with acceleration and stops when easing off it could be valve gear related or possibly little end wear - big end wear would be less of a rattle and more of a knock just as acceleration is reduced at the peak of torque curve. I am curious to know why anyone would be driving this engine above 2300 rpm (max torque) since a gear change should be made well below this and the car would be doing 75mph at 2200rpm in 5th. Remember a diesel does not like to be revved above its max torque curve. If you want more MPG and performance drive with a very light foot - I can get 60mpg out of mine.

[steve_earwig]

I saw an HDi saloon today and it was even louder then mine, it sounded like a black cab!

It rattles at anything above idle 'til around 3k when the note changes to a more constant noise. Also, the more I tread on it the louder it is but it's there even at light throttle openings. I suppose it does sound a bit like a tappet but they usually don't stop at a particular engine speed, nor does a small end.