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Discussion Starter #1
1999 SL500 70,000 miles.
I had the check engine light come on then go off, then on. The code said the mass airflow sensor was the problem. They wanted $390.00 for the part and 1 hr. labor to replace.
The local European parts store told me to try to clean it. $6.00 for the cleaner and about 30 minutes to do the job.
No more check engine light and the performance difference is astounding.
 

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1998 Pano SL500; 1993 SL500; 2005 ML270cdi
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8,861 Posts
It's always worth cleaning the MAF before replacing. I cleaned mine when the car was misfiring and the ASR light was coming on and it completely cured all of the faults.
I just used 96º alcohol to clean the very fine filament by squirting the alcohol from a plastic bottle with a very fine hole directly on to the fine filament.
 

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1992 300 SL,1999 SL 500
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294 Posts
where is the maf?? do you have any pics of it, im wondering if i would need to clean mine. thanks
 

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2000 Obsidian Black Metallic Mercedes SL 320 V6
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4,527 Posts
where is the maf?? do you have any pics of it, im wondering if i would need to clean mine. thanks
Hi 1992300SL if my memory assists me but I might be wrong I don't think you car has a MAF.
Please correct me if I am wrong and in case I am I'm apologizing in advance.

Cheers.
 

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2001 E320 - Brilliant Silver/Ash: 107,000+
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17,193 Posts
wayneg is correct. My hangout is on the W210 forum and there are a lot of owners there who have gotten good results from cleaning theirs. As you'll notice from the DIY, there is a specific cleaner for them. Other things might work, but I'd advise the one recommended in our Sticky.
 

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MB SL600, MB 380SE, Suzuki Grand Vitara, 38' Chris-Craft, Volvo V70XC, and my own two feet...
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4,131 Posts
CRC Mass Air Flow cleaner is the commercial product, and it worked well when I used it.

They don't give you the formula on the can, but I'd be willing to bet it's probably just re-packaged electrical contact cleaner.
 

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SL 60 1998
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386 Posts
BEWARE some electrical contact cleaners can damage plastic - Servisol for one. Always test before use.
I have had some switches lock up solid after some cleaners.
 

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1998 SL500, 1959 220S, 1970 280SL
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777 Posts
If you decide to go the replacement route, which I did because I had a hard failure code, AutohausAZ has them for $265 and free shipping for genuine German-made in the yellow box. I'm told that you need to avoid the ones made in South Africa that come in a gray box.
 

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1999 SL500 Sport 1986 560SL 1999 M3 convertible
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118 Posts
I got my new MAF on ebay, I think I paid $81 plus $15 shipping.
The seller was in Davie, Florida.
 

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95 SL500, K&N, NEOKEN Ported TB, Custom Intake, RENNtech Sport Exhaust, AMG I Monoblocks
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10,980 Posts
I used the CRC Mass airflow Sensor Cleaner (aerosal spray) last night. I have noticed a slight improvements after cleaning the MAF. The engine feels a little more smooth and crisp. Thats about all I can say at this point.
 

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Premium Member
95 SL500, K&N, NEOKEN Ported TB, Custom Intake, RENNtech Sport Exhaust, AMG I Monoblocks
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10,980 Posts
After driving the car more after cleaning the MAF, I have noticed even more improvements in overall engine performance. The engine runs better now during hot days than previously. (95-100 F)

I have experienced (similar) symptoms on occasion relating to the "car wont start on hot day" thread as I would need to give it a little throttle to crank up the engine during hot days.
Cleaning the MAF has basicly fixed this problem for me. Engine cranks up much quicker and with less effort during hot days.

I have about 90,000 miles on a 95.

Could it be that collection of dirt or micro particles built up in the MAF sensor would make it read less airflow, in turn equating in a lack of fuel somewhere in the EFI system causing a weak engine start. What doesnt make sense is why only during a real hot day. Well either way, its very impressive for a couple of sprays from an aerosal can, and I would definately recommend cleaning the MAF especially on cars of age or higher mileage.

Overall, the engine runs noticeably better.
 

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Greek God of the R129
SL500-500SEL-190E
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8,410 Posts
Could it be that collection of dirt or micro particles built up in the MAF sensor would make it read less airflow, in turn equating in a lack of fuel somewhere in the EFI system causing a weak engine start. What doesnt make sense is why only during a real hot day.
Yes you are correct.
The hot wire senses the air volume.
The dirt insulates.
Computer sees that you have less air volume, cuts/ slows the gas timing.
Cleaning helps but is temporary. ;)
On a hot day the air is thiner. :(
Regards.
aam.
 

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Y2K SL500 Silver
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8,660 Posts
I used the CRC Mass airflow Sensor Cleaner (aerosal spray) last night. I have noticed a slight improvements after cleaning the MAF. The engine feels a little more smooth and crisp. Thats about all I can say about it.
Please read the attached CRC PDF.
 

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Premium Member
95 SL500, K&N, NEOKEN Ported TB, Custom Intake, RENNtech Sport Exhaust, AMG I Monoblocks
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10,980 Posts
Cleaning helps but is temporary. ;)

Regards.
aam.
Hi aam,

I am curious as to why "cleaning helps but is temporary"
Are you suggesting that the "real" problem is not of cleaning the MAF sensor?
 

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Greek God of the R129
SL500-500SEL-190E
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8,410 Posts
Hi aam,

I am curious as to why "cleaning helps but is temporary"
Are you suggesting that the "real" problem is not of cleaning the MAF sensor?
I don't know the reason, is it the years, overheating, taking the protective coating, etc.
No I would have done exactly what you did.
If I can get a month or a year out of it, why not.
Regards.aam.
 

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2000 sl500 sport black with tan
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109 Posts
Mine started acting up a year ago
I cleaned it and it worked great
I had bought a new one but wanted to see if the old one was repaired
About a month ago it started getting p0170 again
I did not clean it this time I just put the new one on
I can't believe it got dirty within a few thousand miles
 

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1992 300sl
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159 Posts
I now use a K&N air filter on my 92 300sl and have about 10,000 miles on it. I am about 4k miles away from the 90k check up, so it will be time to clean the filter and will also replace some ignition parts. Where do I find the MAF sensor and how do I get to it. I assume it is somwhere in the intake system after the air filter. How do I find it and what does it look like? Then do I remove the item completely to clean it?
 

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MB SL600, MB 380SE, Suzuki Grand Vitara, 38' Chris-Craft, Volvo V70XC, and my own two feet...
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4,131 Posts
Mine started acting up a year ago
I cleaned it and it worked great
I had bought a new one but wanted to see if the old one was repaired
About a month ago it started getting p0170 again
I did not clean it this time I just put the new one on
I can't believe it got dirty within a few thousand miles
That's the way it goes. I went through that myself. Cleaning doesn't last long, you'll be doing it all the time if you start going down that road, vs. replacing it you get years out of the new one.
 
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