TD5 Engine Noises

[lj80]

Hey Guys
Just picked up a 130 TD5 and had a quick question regarding the engine noises.
On idle and low RPM is tappety like other diesel engines i've drive but then as the throttle and boost increases the tappeting noise noticeably and quickly goes away. Is this normal and can someone explain what is happening.
Also noticed it happening at low RPM when coming down a hill in low first gear.

[Benz]

I can say it's normal. The td5 is a modern (well kinda it's a little old now I guess) diesel and so is quieter. They must of only been able to quiet it down at higher rpm or something.

Not sure how they have done it. Could have something to do with direct injection or perhaps they have changed how the diesel combusts or when it combusts. I'm sure soneone on here will know.

[Blade74]

Not to go off topic too much. You will also notice that when you are cruising to a stop the tapping noise is very erratic until you come to a complete stop then it goes back to a smoother consistent tapping noise.
Also sometimes when you are cursing and don't have your foot on the accelerator it's quiet and then when you touch the accelerator you get that loud injector tapping noise like a truck.

[BilboBoggles]

One way to check if it's real tappet noise, if you get up to about 40kph on a quiet road, in 3rd let go of the throttle. On overrun the TD5 cut's the fuel and you will lose the combustion noises. If it still taps then its a real tappet type noise.

Another thing to watch for on td5's over 200,000k's that have the original clutch, is a damaged flywheel, or a worn harmonic balancer, these can show up as all sorts of odd nasty knocking sounds.

That wobbling idle you get when you coast to a halt in neutral, or if you roll along in neutral, is a funny feature of the EU3 map. Supposed to dissapear with a performance map, but it's normal and should stop after 2-3 seconds when you halt.

One way you can quiet down the td5 is to add Two Stroke oil, seems to make a noticeable difference on mine, much quieter.

[lj80]

Thanks.
Yes i have noticed the lumpy idle as well on coasting.
Good to know these little quirks are normal. I'm sure there will be alot more to come yet.