ALH: Motor Noise (Ticking/Chirping) Fix

Before I describe my problem, here are the facts:

SEAT Leon, ALH (90 hp TDI), *** chip, 25,000 km (10 months).

'For the past few days, the acoustics of my engine have changed slightly. During cold or warm starts, you can hear a faint chirping or ticking sound (both inside and outside) at a regular interval. When I accelerate, the speed of the sound increases (in parallel with the combustion noise). It's particularly noticeable if you maintain a constant speed, for example, at 1400 rpm (any gear works, but 2nd, 3rd, or 4th is best), and then gently accelerate. At certain engine speeds, it's quiet, and at high speeds, it's barely audible. I've already tried to locate the source, but I can't pinpoint it exactly. The sound is also present when the engine is idling! I recently checked the target/actual values for idle speed using VAG Com with the engine warm. All values were OK, except for the pulse width valve for the injection start, which should be between 3 and 80, but was at 2.8. Is this value significant? The power and fuel consumption values are as usual (OK). Otherwise, I haven't noticed any other irregularities (except for this unpleasant noise).'I have to say that I've heard this noise before a few times, but it went away and wasn't as loud. The weather conditions don't seem to play a role. If I take it to the mechanic to show him the problem, he'll probably hear nothing (or pretend not to) and tell me it's normal. It would be great if I could express a specific suspicion. Should I perhaps log certain data points while driving and post them here (if so, which ones)?

Thank you!

It can be particularly easily triggered by, for example, consistently driving at 1400 rpm (the gear doesn't matter, but 2nd, 3rd, or 4th is best) and then very gently accelerating.

Hello,
I suspect it's one of your glow plugs. I've had the same issue with my Golf 4 ALH for a while. It only happens during the warmer months, in the same load and RPM range. So far, I haven't done anything about it. The idea would be to replace the glow plug on cylinder 1, test it, and if that fixes it, great. Otherwise, replace it on cylinder 2, and so on. Or, buy four new ones (which is expensive!). Using an electrical circuit to diagnose it probably won't reveal anything. At least in my case, the noise isn't detectable when the engine is stationary because the amount of fuel being injected is less than 8 mg.
Regards,
Ole.

Hello,

Quote:

Besides the keyboard-controlled valve for the start of injection, which should be between 3 and 80, the value was 2.8. (1)

If the error memory doesn't show anything related to the fuel injection start control, I wouldn't rotate the fuel injection pump.

However, I am somewhat concerned about the following: If the chirping sounds are coming from your timing belt tensioner, it could potentially shift the static injection timing in such a way that (1) occurs.
Then it's time to act.

Before you start replacing the belt tensioner and idler pulleys (for timing belts or ribbed belts), I would first check all the tensioners and idler pulleys yourself, as it's something you can do yourself and it doesn't cost anything.

Best regards, Rainer.

@ ole:

What's the mileage on your ALH engine? I've only got 25,000 km on mine, and the noise started earlier, so I can hardly imagine it being due to wear and tear. Maybe the noise will go away again, but it would be nice to know where it's coming from and whether it occasionally occurs in other TDIs as well.

@ Rainer K.:

I'm going to log the throttle valve position related to the start of injection while driving. It's not actually coming from the direction of the timing belt.

Hello.
My ALH has 67,000 km on it. At approximately 5,000 km, I replaced all four glow plugs with new ones from ASV. The noise has been present almost from the beginning, so I believe wear and tear can be ruled out.
Regards,
Ole.

So, you're saying that this is a typical phenomenon for ALH?

No. I believe it's a nozzle problem, which can occur in all types of direct injection systems. I've also heard something similar from Bosch.
Do you have any new insights (regarding the ZR_Spannrolle?)?
Regards,
Ole.

@ ole:

I couldn't find anything unusual. It's probably the nozzles.

What do you think I should do? Should I just ignore it (despite the warranty) and continue driving normally? Are there likely to be long-term damages if I don't do anything now? Most drivers probably wouldn't even notice such a noise, and there's no noticeable loss of performance. I'm going to try filling up with some 'Super' diesel from Aral soon, because as they say, faith can move mountains...

After driving approximately 600 km with the Aral Diesel, the noise has gradually become quieter. Today, I paid close attention, but I could no longer hear it. Is this a coincidence, or was it actually related to the diesel quality (Jet Diesel)? As you know, a gasoline engine will make a certain noise if the octane rating is incorrect, but what about diesel?