TDI Engine Noise

[TDIRules]

I've clocked up just over 1100km in my new MkV 2.0TDI and have noticed that the diesel chatter seems to be louder. It's not that there is any specific noise that has me concerned, it's just the general engine noise. To me it's noticeably louder (not so much that I have to turn the radio up or anything), however I'm sure to anyone else it wouldn't be any different. When I picked it up the dealer said that the noise will get louder and then quieten down as the engine beads. I did take this with a grain of salt.

So my question is, has anyone else experienced this? Is it normal, or is it just my mind think playing tricks, or has it just been a long week and I'm in desperate need of the long weekend!

[gregozedobe]

I have heard of TDIs getting slightly louder as they get run in (and freer revving), but usually around 10,000Km or more. Some people say they also seem smoother too.

Is it more noticeable at idle, or when you are near a wall or another vehicle ? My 2.5 TDI (18,000Km) is distinctly louder when someone pulls up next to me at the lights, obviously the noise reflects off their vehicle back to me.

[cetane]

I found that the clatter did increase slightly after initial running (can't remember the kms) but it seemed to quieten after about 12,000km. You have to remember that PD motors are noisier than CRI motors so don't compare it with say a Peugeot or Citroen. You'll also notice that after you slow down when entering a low speed limit zone and have a slightly open throttle the clatter seems louder. This is normal with PD motors. Really, you have nothing to worry about.

[Greg Roles]

Man I thought it was just me! I'm at 800km's, and I was just thinking the other day that the rattle sounded a bit louder overall. I kinda like it, for I didn't buy a diesel for the sonorous engine note, so you might as well make it obvious!:D

[Mischa]

I found that the clatter did increase slightly after initial running (can't remember the kms) but it seemed to quieten after about 12,000km. You have to remember that PD motors are noisier than CRI motors so don't compare it with say a Peugeot or Citroen. You'll also notice that after you slow down when entering a low speed limit zone and have a slightly open throttle the clatter seems louder. This is normal with PD motors. Really, you have nothing to worry about.

for those who dont know, cr = common rail = more otto like characteristics
PD = Pump duse = direct injection = more truck like characteristics

***hey mate.... common rail injected TDi's are still direct injection.

TDi = Turbocharged Direct injection.... just FYI - mod***

[bluey]

As I've been reading, the noise relates to diesel combustion. It can be reduced by pilot injection, EGR, and higher cetane fuels (eg biodiesel).

See:
http://www.eng-tips.com/viewthread.cfm?qid=139341&page=7
which also has a broken link to a fascinating engineering lecture:
http://web.archive.org/web/20050430145007/http://me.queensu.ca/courses/MECH435/6.+Combustion+in+IC+Engines.ppt

I presume common rail permits decoupling of fuel pressure from engine position but that is is still possible engineers will get rid of the noise from unit injector systems in time as they can achieve higher pressure.

[Pumpe-Düse]

According to VW, in the Polo brochure, TDI = Turbo Diesel Injection.

[bluey]

Interesting that higher cetane fuels should be quieter. Australian diesel fuel legislation specifies minimum cetane 46. Polo glossy brochure says Diesel 49CN. Golf glossy says Diesel 51CZ (which I presume should be CN).

This Premium diesel is B20. http://www.farmersfuel.com.au/Archive/Premium%20Diesel.htm

BP Ultimate diesel is the only diesel BP makes with a minimum cetane rating of 50 and you can only get it in Perth!

How do you get slightly higher cetane diesel here to meet VW requirements?

[bluey]

[deleted duplicate]

[greygolf8]

Buy a jerry & fill with B100. add 2l+ to tank everytime you fill with dino diesel ... ??

[GoLfMan]

bugger it, when is Vic going to get premium diesel :(

[bluey]

Victorians can get ecofuels, which should have higher cetane since biodiesel has a higher cetane - see:
http://www.exploroz.com/Forum/Topic/49001/Biodiesel_Availability_in_Victoria.aspx

On my second tank of diesel wondering if random variability in cetane rating is the cause for variability of diesel clatter. Polo seemed quieter at cruising speeds and the computer thinks it's using less fuel at idle (0.8L/hr vs 0.9L/hr previously). or maybe its my imagination.....