Cleaning hot-film type MAF sensor?

Hi,

I tried cleaning the MAF sensor on my car having a 1.6 TDI (CLNA) engine. I used CRC MAF sensor cleaner, which, as per CRC, can be used on both hot-wire and hot-film sensors.

I do not feel it really helped after spraying on the sensor, as instructed. I also noticed the dirt along the inside of the enclosing plastic, was still left as is, even after spraying the cleaner on it and having it dry away.

I manually wiped down the dirt from there, without touching the sensor at all.

However, the spray did clean the dirt on the white part of the sensor.

Is it the case that the spray never actually reached the film, as it seems to be concealed?

I am including some pictures of the sensor.

We don't have your engine in the US but cleaning the MAF is usually a solution
in search of a problem. Think about it: where is the dirt coming from?
There should only be clean, filtered air at the MAF. If there isn't, find out why.
MAF's go bad over time but dirtiness is rarely the cause, IMHO.

X2 what flee said. Check your air filter.

The air filter is changed every 15,000 kms here, due to this being a high dust area.

Nonetheless, even if I take out the air filter after about 2,000 kms, from the previous cleaning, it is still full of dust. I tend to clean it right in between two consecutive air filter change.

This time I additionally did it while cleaning the MAF sensor, (the 2,000 kms thing).

The reason I wanted to clean the MAF sensor is because I noticed the fuel efficiency had dropped significantly.

I would appreciate if you could let me know about a better way to clean the MAF sensor.

How about making the pichers a bit smaller?

halfbytecode said:

The air filter is changed every 15,000 kms here, due to this being a high dust area...

Click to expand...

I would check the fit of the air filter in the box. If that much dust is getting past it, something isn't right. And, as KLXD asked, can you resize the pictures?

I find that the MAF sensors can gather an oily film from the crankcase vent oil vapors drifting down through the intake tube after the engine has been shut off. I don't know how it could get that way otherwise.
You aren't by some chance using a K&N or other oil treated air filter are you?

KLXD said:

How about making the pichers a bit smaller?

Click to expand...

Sorry, I did not realize they were huge. Turned out to be gigantic.

1854sailor said:

I would check the fit of the air filter in the box. If that much dust is getting past it, something isn't right. And, as KLXD asked, can you resize the pictures?

Click to expand...

The dust visible in the pictures, near the MAF sensor, has accumulated over years.

I was talking about the dust in the air filter, and its enclosure, to explain the high dust situation in this area.

JETaah said:

I find that the MAF sensors can gather an oily film from the crankcase vent oil vapors drifting down through the intake tube after the engine has been shut off. I don't know how it could get that way otherwise.
You aren't by some chance using a K&N or other oil treated air filter are you?

Click to expand...

I have never used oil treated air filters. Always used stock VW filters, and other stock components.

halfbytecode said:

...I was talking about the dust in the air filter, and its enclosure, to explain the high dust situation in this area...

Click to expand...

Understood, but if the dust is making it to the MAF sensor, there's a either a fit problem with the filter element, or a leak downstream of it.

1854sailor said:

Understood, but if the dust is making it to the MAF sensor, there's a either a fit problem with the filter element, or a leak downstream of it.

Click to expand...

Since the MAF sensor is screwed and glued to the side of air filter enclosure!

The only thing I can think of is the missing O-ring below the air filter, which the dealership guys seem to have misplaced.



I do not know how the missing O-ring affects the air filter/MAF sensor.

Could you tell me a way to clean the MAF sensor film?

That's too much dust getting by the air filter.
Try greasing the sealing surfaces between the filter and airbox. Any grease will do.
As far as cleaning the MAF, spray it as best as you can but don't expect a miracle.

flee said:

That's too much dust getting by the air filter.
Try greasing the sealing surfaces between the filter and airbox. Any grease will do.
As far as cleaning the MAF, spray it as best as you can but don't expect a miracle.

Click to expand...

Thanks. Should I also try getting a replacement O-ring of the same specifications?

Furthermore, I still do not understand how I should access the film, while spraying the MAF sensor cleaner.

It seems the spray is only getting onto the white plastic of the sensor "body".