MAF replacement as preventive maintenance item?
 

I thought I would cast a wide net for opinions and experiences regarding replacement of the MAF sensor as a PM item after a certain number of miles. In other words, how long is a MAF going to last?

My logic is:
1. All Bosch items will fail when you don't want them to
2. MAF's are Bosch items (and they are subjected to repeated heating and cooling cycles in an unfreindly environment)
ergo, MAF's will fail when you don't want them to.

My (admittedly limited) experience with MAF's >100K miles has shown that they fail between 100K and 130K miles.

So, I'm thinking I ought to just replace the puppy at 100K and be done with it. This way I can buy it on teh cheap and replace on my schedule.

Feel free to opine about O2 sensors as well. It's a big chunk of change, but if they set you up for another 100K of trouble-free driving, maybe it's not such a bad idea. Kind of like the battery - why wait for battery death to start tormenting you with strange gremlins and symptoms in a futile effort to save a dollar or two.

Prevention is always good, as long as it does not hurt your wallet that much. What are you looking at in cost for MAF?

BTW: what is your ride?

Longevity for both depends on the model and type.

MB has used other brand fuel systems as well. Siemens has made the 4 cylinder engine fuel systems since 2000. Also MAF's on other brands fail as well.
Siemens also make a lot of the BMW MAFs & their failure rate is high as well.

I really believe that the extended AIR filter changes(60K) has a lot to do with the failure rate! Do your car a favor & install a new filter every 25K-30K miles!

You need to state the car and engine.

Bosch's weak period seems to have coincided with first years of M112/M113 engines.

Elsewhere it's been pretty good.

The previous owner of mine S500 had the MAF done. the labor was virtually nothing, but the parts is $$$. I don't know what vehicle you have so it might not be bad.

Here is my take on changing parts:
Yes, a lot of Mercedes' components are prone to failure, but I have to draw the line somewhere because they are just so pricey. If I start replacing parts in advance, then I will be buying MAF, Cam Sensor, O2 sensor, fuel pump, and list goes on and on.

You can see it adds up very quickly and I can't afford that. I just pray every week and let it ride. I do all the recommended maintence. If anything out of normal breaks, I know I have this forum to help me out and fix whatever the problem is.

The worst case is bring it to a reputable Mercedes shop in Houston.

If you like to be safe and be prepare for failure. Just look for cheap parts online whenever they are available. This way, you will have time to bargain shop while the old parts are still working.

The engine is a '99 M113.

As to Bosch quality, I think they all come from the Bosch plants in China anyway. (Plant Locations: Beijing, Changsha, Chuzhou, Dongguan City, Hangzhou, Hong Kong, Nanjing, Shanghai, Suzhou, Wujin, Wuxi, Xian, Zhuhai). Not that different from everybody else, though.

Believe what you want, but my experience working with Bosch as a supplier is that they came across as arrogant monopolists who were seldom responsive in addressing quality concerns. I would take the behemoth Siemens any day of the week.

As much as I believe/subscribe to preventive maintenance, never heard of a MAF sensor leaving anybody stranded.
Therefore I would not consider it a " replace on a mileage-based " item. ;)

I'm also going on history where the diagnosis was a PITA. Granted, that was on my W124 with OBD 0.1, and the computer was able to compensate for several minor problems until the MAF failed as well. Then it threw off several "red herring" codes until I finally nailed the real culprit: MAF.

I had just read another post where someone was dynamically testing the MAF for flow rate and it got me thinking that I should just replace it to pre-emptively strike at another MAF diagnosis quagmire. If the things would just clearly fail, then no big deal, but the failure likes to creep in on little cat feet.

I tend to think like m.b.doc, I replace the air fitler every year, about every 22k miles. I clean my maf with maf cleaner when I do the air filter. I don't worry about replacing things just because they are bosch, ever own a german car with a Lucas electrical system? I do tend to follow the maintenance schedules, adding a coolant flush every two years, and a tranny service at the same time. Most computer controled cars will run without a maf, or with it unplugged, I spend time thinking about single failure components more.

Best wishes, Chuck

Royal pain if the MAF happens to throw a CEL just before a required emissions test. Potentially some diagnostic time to sort out the CEL only to finally end up being a simple-to-change MAF. In that case, the preventative maintenace theory might make a lot of sense.

Buy the MAF now, and keep it in storage until you need it - because you will never buy it that cheap again.

I wouldn't when it breaks replace it. They are super easy to get at, and pretty damn expensive.

When it throws a code, read it and replace it.

Well the most important thing I've seen so far is that no one claims theirs lasted forever :)

From that point of view it makes sense to at least buy the thing in advance so that I can get the best price for it. The MAF insert route at around $140 seems to be the best deal I can find.

I suppose this could be called a consumable item. When I searched for information on the MAF sensor (MB calls it the Air Mass Meter, or AMM) I got the impression most people needed to replace it at around 70K.

My search also found information that warned people of cheaply rebuilt sensors that use a VW sensing element, which has different electronic characteristics that are bad for the engine management system. The replacement unit should only be a Bosch. The price of these is near $250.

Some vendors sell just the insert. If you can find just the insert you stand to save some money.