Sport Air Filter: Carbon Buildup & Problems

Hello,

After an optical diagnosis of the mass airflow sensor (MAF), I noticed a puzzling layer of soot behind the flexible intake pipe (between the MAF and the turbocharger). At first, I thought the turbocharger might be malfunctioning, but there was already soot clogging the filter screen of the MAF sensor as well.

Is the sports air filter to blame for this buildup, or are these deposits normal after 200,000 km? Is the sports air filter (which, yes, I know doesn't really offer any benefit – it's just recyclable) significantly worse in terms of filtration compared to a paper filter? Can cleaning the mass airflow sensor (MAF sensor) restore it, or is there still mechanical wear present?

I hope I don't hear again that everything has already been posted and that I should just search for it? I see this as a user forum, not as a reference or showcase forum.
I would like to contribute and try my best to help maintain this excellent forum as a redundant Diesel-DB resource Destroy me .

Thank you very much.

Tobi.

Hi hi, you asked for it .

A search for '*air filter*' yielded, among other results, this link.
/viewtopic.php?t=5262&highlight=%2Aluftfilter#32928

Regarding cleaning: It might help, but it's not guaranteed (you could try brake cleaner). Being clean alone doesn't necessarily indicate proper function. A proper check can only be done using a diagnostic tool, such as VAG-COM.

The layer you refer to as soot is likely oil mist from the oil-soaked sports air filter, combined with small particles that the air filter didn't filter out.

Please take a look at the link I've provided, and I think you'll want to get rid of that thing as soon as possible.

Regards,
Private.

The layer you refer to as soot is likely oil mist from the oiled sports air filter, combined with small particles that the air filter didn't filter out.

Please take a look at the link I've provided, and I think you'll want to get rid of that thing as soon as possible.


Oh, nonsense, sorry. Which filter did you actually install? If it's a K&N filter, the 'experts' here should really check it out, there's a certificate of compliance available.
I've also had good experiences with K&N oiled air filters. Those dirt deposits were also present with the original paper air filter, which doesn't filter everything out either.
Anyway, I haven't had any problems with it in over 160,000 km (neither with the engine, MAF sensor, or anything else), but learning how to properly lubricate it takes practice.

That's the key point.

Regular and proper maintenance

'With a '2-3mm layer of dirt,' as often stated in the instructions, the filter is long overdue for replacement.'

I like to repeat myself.

The HFM-5 requires the following specifications for air filtration:

Maximum particle size on the clean air side: 20 µm.
Rejection rate >99% throughout the entire filter lifespan.
NO OIL MIST.
DO NOT expose to water.

Particles can cause abrasive wear, and they also accumulate at the leading edge of the measuring film, disrupting the aerodynamics and thus affecting the measurement result.
For particles larger than 60µm, mechanical damage to the HFM can already occur.

Oil and water act like a glue for particles, and naturally strengthen the whole structure.
'That's the danger with fabric filters. Too much oil can be carried over, while too little oil or inadequate maintenance can allow particles to pass through. If a filter is overloaded, even particles that have already settled can be carried over at high gas velocities...'

CU Gremlin.

I installed a J&R filter from ATU and have been using it for 20,000 kilometers.
I just wanted to adjust the cost factor. Because, considering the price, it pays for itself after approximately 60,000 kilometers, including the cost of oil.

According to what I've read in the press, diesel soot particles are strongly suspected of causing cancer, due to their size.
A paper filter might also let these miniatures pass through.

Since the textile filter is only sold if it's good quality, and I was advised honestly (or at least, I hope so), I'm willing to trust it.

I had tried placing a textile filter mat behind an air conditioning filter mat. I wasn't really confident in that perforated thing and its supposed ability to collect dirt through static electricity. In the air conditioning filter mat, I only caught oil droplets (probably an exaggeration) over a distance of more than 3000 km.

'Has anyone else experienced an oily soot film or similar buildup in the intake manifold with a vehicle having 200,000 km (approximately 124,000 miles) on the odometer?'
Isn't that normal, or could it possibly be an indication of a leaking turbocharger?

Hello,
On this topic, I would like to add my two cents.
I've been using a K&N filter in my 1Z for about 150,000 km. About 2 months ago, I had to replace my first Pierburg mass airflow sensor (MAF). I think it lasted quite a while.
It is understandable that Bosch and VW are describing such alarming scenarios, especially when one considers the price of such a piece of "white paper" (referring to a document or report).
I learned in vocational school that an oil bath air filter provides the best cleaning performance. However, it may not be ideal for the original equipment manufacturer (OEM) due to the higher price, and perhaps the engines would then last too long?

Best regards, Benno.

Benno wrote:

Hello, On this topic, I'd like to add my two cents. I've been using a K&N filter in my 1Z for about 150,000 km. About 2 months ago, I had to replace my first Pierburg mass airflow sensor (MAF). I think it lasted quite a while. It's understandable that Bosch and VW are describing such alarming scenarios, considering the price of such a piece of "wiping paper." I learned in vocational school that an oil bath air filter provides the best cleaning performance. However, it may not be ideal for the original equipment manufacturer (OEM) due to the higher price, and perhaps the engines would then last too long? Hi Benno

"In the case of the A3 BJ98, that's definitely not the case. I maintain my statement that such a filter is garbage in this car."
Meiner ist übrigens zu verkaufen, ist von BMC. FP15 EUR.
Reason: https://community.dieselschrauber.org/en/viewtopic.php?t=2917

Best regards, Rainer.

I learned in vocational school that an oil bath air filter has the best cleaning effect. It's probably not optimal for the original equipment manufacturer (due to the higher price), and maybe the engines then last too long?



That's due to the rapidly accelerating decline in human intelligence...

Considering how rarely vehicles are brought in for service these days, and how the filters often look in those cases...

What do you think would happen with a standard dry-type or even an oil-bath filter?

and the 'worst-case scenario' is not just scaremongering.
Due to exhaust emission regulations and customer demand for smoke-free racing diesel engines, adjustments must be made to the fuel-air mixture.
That is to say, the requirements are becoming increasingly demanding, and the constraints are becoming ever tighter.

The hot-film mass flow sensors must bear the cost, and the most suitable type is the hot-film LMM. While hot-wire and platinum resistor sensors are still relatively insensitive to water and oil (hot-wire sensors are even self-cleaning), the hot-film consists of a 2µm thin semiconductor layer. And that layer is susceptible to dirt, oil, and water. However, I can use it to measure very small changes in air mass extremely quickly, and even determine the direction of the flow.
And before the complaining starts again: Bosch already reacted to the HFM-5 issue and implemented various improvements, and that was quite some time ago. Interestingly, older versions are still found in current VAG models, and they are still being installed incorrectly (e.g., it is not permitted to take the intake air from the radiator grille, as the distance to the intercooler is too small...).

CU Gremlin.