S320 CDI Mass airflow sensor replacement

[Steve.D]

My old girl (S320 CDI - Year 2000) just hit 60,000 miles and won't kickdown or accelerate strongly. I just had an independent service a month or so ago and high oil level warning flashed once on a recent long trip so I thought that might be related. Otherwise engine seems fine, no smoke and eventually gets up to speed fine, although gear changes appear to happen early. Done research on this BB and others and thought I'd change Mass airflow sensor but no idea where it is located (is it inside air filter housing?). Thanks in advance for info or ideas.

 

[Valps]

Steve, On my E240 it sits between air filter and engine. One end of MAF jubilee clipped to hose, and other side of MAF I believe was attached to hard plastic pipe. The MAF had an electric plug attached.

Hope this helps. If you think it would help I'll photograph mine and post it here.

 

[TKB13]

The MAF is an expensive item to replace. It's often recommended that soaking the sensor in brake fluid overnight is an ideal cleaning method.

 

[tamrsoft]

Be careful, the MAF is a sensitive electronic component and brake fluid or brake/carburetor component cleaner could damage it. Use an alcohol based electronic component cleaner (£3.99 in Halfords) and give it a good spray, if its dirt/oil contamination causing the problem then this should cure it.

 

[TKB13]

The MAF is an expensive item to replace. It's often recommended that soaking the sensor in brake fluid overnight is an ideal cleaning method.

I'm just quoting what many dedicated MB owners advocate. (Not talking about immersing the entire unit, just the 'wire thingy' sensor).

 

[tamrsoft]

I agree, I have read these articles as well. Trouble is these fluids can be very aggressive (eg brake fluid on paintwork) so its difficult to be sure about the possible long term corrosive effect on the fine film surface of a potentially very expensive component. I prefer to use cleaning fluids that I know to be safe.

 

[Steve.D]

Thanks all. I managed to extract airflow sensor by: undoing three bolts holding air filter in, undoing clip holding air hose on output (radiator end of filter housing), taking off engine cover by unscrewing the six retaining bolts. This allows cable/connector to sensor to be disconnected. Can now unscrew sensor itself by unscrewing the two holding screws and sensor comes out. Have to say it looks brand new but still suspect this is the problem so have a replacement on order.

Thanks again all your views, most helpful and will post result when I replace mass airflow sensor shortly.

 

[eGuru]

sensor

Steve
Had similar problem to yours on my S320 CDi. Fitted new sensor last week and drives like new!
Cost of sensor was £60 plus fitting.
Jay

 

[TKB13]

£60 certainly seems a great price by MB standards!

 

[Steve.D]

Jay
Was your part from Mercedes dealership or do you have a better source?
Steve

 

[eGuru]

Jay
Was your part from Mercedes dealership or do you have a better source?
Steve

Steve
Part was supplied by my local indie, Peter Hodge & sons. By all means call them and see if they will sell you a sensor. Tel. 01604 588911. They are open until noon Saturdays.
I believe they ordered 6 of these sensors last week. Feel free to mention my name.
Jay

 

[Dieselman]

MAF for CDI engines are usually about £50 or so from the dealer.

 

[silverarrow]

please all with maf have a lookat www.bba-reman.com they will test the old one

 

[Steve.D]

Finally got around to changing MAF today. Purchased part from local Merc dealer for £68 inc vat. Change took 10 minutes which given local dealer quoted 2 hours at £90/hr for the job (+ vat) made me feel good. Car now drives as I remember it, smooth acceleration, instant kickdown and masses of torque.

My sincere thanks to this board which helped me diagnose the problem and the guidance for a diy changeout. Thanks all.

A final question. Do you think it advisable to run the 320 CDI engine with a fuel additive such as Redex after such a change? Thanks again guys.

 

[silverarrow]

yep re fuel injector cleaner but use millers and buy in bulk costco or in france on holls its 1/8 th of the uk price
also have a service in france save??????????

 

[silverarrow]

ask the mb service dept how can it take 2 hrs to change
WOULD YOU GO BACK TO THIS DEALER SORRY STEALER

 

[Dieselman]

Ditto Silverarrow, use an additive every tank, but you won't get Millers from Costco.

 

[Birdman]

ask the mb service dept how can it take 2 hrs to change
WOULD YOU GO BACK TO THIS DEALER SORRY STEALER

This is the sort of thing Mercedes UK should be told about. They are trying to sort out dealers who fleece the customer but need to know who they are.

 

[gartmore]

Airflow sensor

I've just been told by MB of Glasgow that my ML270's Air mass sensor needs replacing - no kickdown and gutless - at a cost of £230. Last month we faced a bill of around £2200 for 2 cats and an exhaust after the one of the cats tried to leave by the pipe, although MB contributed £750 we still had a sizeable bill. I see an 'airflow meter' or 'air mass meter' on ebay for £60, is this the same thing? Thanks

Ken

 

[Seamster15]

Yes its the same, but check part numbers first!