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2001 C240 SPARK PLUGS, OIL CHANGE, MAF - HOW TO REPAIRS D.I.Y.

123K views 52 replies 45 participants last post by  mumupunx 
#1 ·
OK this D.I.Y. Post should aid you in a couple reapairs on your 2001 C240, but should apply to the 1999-2005 c240's as well.

Background before starting, my Check Engine light was on and my indications from the car were poor pickup or slugglish/surging acceleration. Like it wants to go smoothily but then choked a bit. After the car warmed up it wasnt so bad, but still present. Also my Codes given were Bank 1 Fuel Trim & Bank 2 Fuel Trim.

Replacing your MAF - AMM - MAS (Mass Air Flow - Air Mass Meter - Mass Air Flow : Sensor)

I did all 3 of these today. I have no experience with a Mercedes Benz, just a good working background in Mechanical work. It took me 3.5 hours to do all 3 repairs. I used a mechanics bay at work, that is provided by the Army. All tools and lifts.

Also I am NOT a MECHANIC, but these techniques should work for your c240. If you find any errors in this guide please post, it only helps us all.

ONE LAST THING. After I reconnected my battery I got a ESP MALFUNCTION - ESP - Electronic Stabiliy Program Not found or Not installed.

To correct this. Start the car. turn your wheel full left, then full right, then full left. Turn off the engine, and restart.
This technique Reprograms the ESP.

TOOLS Needed:
1 - Standard Flat Head Screw Driver
1 - 10mm socket and socket wrench and 10" Extenstion if you so choose.

Parts Needed:
1 MAF (Will be refered to as MAF for the rest of the post)

REPAIR:
Use the 10mm Socket wrench and remove the Negative and Positive Cables.

Remove the plastic intake tubes, just compress the tubes and they pull off.

Remove the front Engine cover. Pull the end closest to the front up the car up then toward you.

Remove the Rear Engine cover. Pull Up the front and then the rear end.

Remove the plastic ring around the top of the MAF.

Unplug the MAF

On the Back of the MAF there is a metal clip, I used my finger to pry it back, but you could use a screwdriver.

Remove the MAF and replace with new one.

Reconnect the Cable.

Attach Plastic Ring.

*At this point you can reconnect your battery and see if
your check engine light is still on.

DONT ERASE YOUR CODES BEFORE STARTING!!!
Ok if the MAF is the cause of your CEL (Check Engine Light) then it will go out on start.
(Keep in mind that your allowing unfiltered air into your engine so this should only be used for a quick check)

If your CEL doesnt go out your MAF may not be the problem.
Now that this is finished you would reinstall all covers and Done!

SPARK PLUG REPLACEMENT:
TOOLS NEEDED:
1 - Torx Socket... Not sure on the size.
1 - 3" Extention 3/8" Drive
1 - 3/8" Drive Socket Wrench
1 - 17mm Spark Plug Socket
1 - Spark Plug Boot Removal Wrench
Pen & Paper

Parts Needed:
12 - Spark Plugs
1 - Gapper
1 - container of Anti-Sieze
Rags.

REPAIR:
Use the 10mm Socket wrench and remove the Negative and
Positive Cables.

Remove the plastic intake tubes, just compress the tubes and they pull off.

Remove the front Engine cover. Pull the end closest to the front up the car up then toward you.

Remove the Rear Engine cover. Pull Up the front and then the rear end.

Now just as a tip I started with the passenger side of the engine, because it has more room you'll find this side of the engine is a bit easier to work on and if you can do it on this side your not going to be able to finish the other.

Ok before your start verify the battery is disconnected.

Draw a diagram of the wires so that you dont forget.
remove the Torx bolts from the 3 Coils on top of the Valve cover.

Remove the top coil connection cables
start in the front of the car and remove the spark plug boots.

KEEP COILS IN ORDER. It shouldnt matter IMO, however IDK if it does and I wouldn't try it.

Ok just as a hint your first 3 plugs from front to back do dont have to take you socket apart,

But 4 & 5 you'll have to seperate your extention from the socket in order to get it on the Plug.

The last spark plug is a bit of a pain. You will have to put the socket on the plug, then the extention, then the socket.

When you remove the last plug you will have to take it all apart to get it back out too.

Gap your new plugs, apply Anti-Sieze to the threads and install.

Replace coils boots(They will click when they are on all the way) and install coils from back to front.

Replace top connections on the coils. Done.

I would suggest reconnecting your battery at this point and starting your car. Only Because if you didnt get your spark plug boots back on all the way that cylinder may not fire and it would be alot easier to troubleshoot.

Same install technique on the Right side of the engine. (Be sure to Draw the diagram out again because its different on the Right side.)

Once done with both sides reinstall engine covers and intake tubes, and reconnect battery.


CHANGING OIL:

TOOLS NEEDED:
SMall MM Socket (Smaller than 10mm, not sure on size)
Socket wrench
1 - 13mm Socket for Drip Pan
Drip Pan (Capable of holding 8.5 qts)
Jack or Lift

Parts Needed:
9 - 1 QT 5w30 FULLY SYNTHETIC Oil I use Mobil 1
1 - Filter for C240 (Comes with 4 or 5 rubber seals various sizes)

OIL CHANGE:
Just to let you know I used a Lift to do mine. Make things so easy.

OK. To start let your car sit for at least 10 mins so most of the oil is in the oil pan.

Remove the Oil filter cap, located on the front drivers sized of the engine compartment, just in front of the oil cap. While your there, remove that cap as well.

Be sure to set some rags down so you dont get oil everywhere.and pull out the cap, which kinda look like a
Turkey baster.. LOL Anyway pull that bad boy out and set it in your drip pan and remove the filter.

Raise the vehicle and remove the rear engine skid plate. (There are 6 screws to get this thing off)
set aside the skid palte and screws and exposed now is the oil pan and 13mm oil pan bolt.
Set your drip pan in place and remove the bolt. Allow oil to drain.

Replace Bolt and skid Plate.

Lower vehicle. Install new filter.

On Filter cover remove 1 at a time old seals and replace with new ones that came with your filter.

Relace Oil Filter cap.

Fill with 8.5 Qts of Oil.

Turn key to the 2nd position and page through to the oil page and check level. If it says ok.

Replace Oil cap.

And your done.

Again if you find any errors please post.

NeV
 
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#33 ·
Just found this site, some great info, thanks a lot! :thumbsup:
So I am about to change out my MAF sensor, and was wondering if it is actually necessary to disconnect the battery to do so, since I will be unplugging the part. I saw the post about stepper motors, and am not sure I really want to screw something else up!

Regards,

Gary
 
#36 ·
FYI, I changed the spark plugs on my 2001 C240. I HIGHLY recommend getting the plug wire remover. It was incredibly difficult to do it without this. Even with that problem, and this being my first time doing anything like this, it took only 3 hours. Dealership wanted to charge me 3 hours labor at $440. I bought all needed supplies for this and it cost less than $50.

Only problem was that it wouldn't start after. It needed a computer reset which I got from the dealer for free.
 
#38 ·
No photos, but look at the original post. I had some different issues however. I would have preferred a 4" extension rather than 3" or maybe both. It was really hard getting in there with the 3". The 17mm spark plug socket didn't fit because whomever had the car before me had normal spark plugs and so I used a standard size spark plug socket.

By Torx socket, it was actually just a star screwdriver end. Just get a cheapo set for a couple bucks and it will come with what you need.

Try to do each plug one at a time and replace the wires as you go. As you get into it, you tend to forget where you left off. I replaced the same plug twice.

SPARK PLUG REPLACEMENT:
TOOLS NEEDED:
1 - Torx Socket... Not sure on the size.
1 - 3" Extention 3/8" Drive
1 - 3/8" Drive Socket Wrench
1 - 17mm Spark Plug Socket
1 - Spark Plug Boot Removal Wrench
 
#40 ·
Honestly I was scared at first to even think I could possibly do this. However with the help of you guys it wasn't actually that bad. Removed the cover, had,

1 - Torx Socket... 1 - 3" Extention 3/8" Drive
1 - 3/8" Drive Socket Wrench
1 - 17mm Spark Plug Socket
1 - Spark Plug Boot Removal Wrench.

Some of them were seized, 2, however just took my time and slowly went at it and no problem. I had no oil or anything, i was surprised (@118k) to see no dirt, clean as a whistle! Put back the top, the coil packs took some fine tuning, but nice to know I saved myself again some more money thanks to you wonderful guys! :)
 
#45 ·
Today I decided to try a topside oil change where you siphon out the old oil with an extractor (mityvac). This on a USA 2001 C240 with a M112 V6. Of course this year/model doesn't have a dipstick, but mine has a dipstick tube. Strangely, the dipstick tube is at the back of the engine by the firewall... Some posters think this is the transmission tube, but no, that is in the same place, but lower down and not visible with the engine cover on. I took a photo to show the difference. My oil change was successful. I sucked about 8L out through the top.

See photo.


Will
 

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#47 ·
Once you do a topside oil change you will never "go down" again to open the drain plug. The one gallon can with the vacuum pump gets nearly all the oil out. Mobil 1 will never form sludge so this should negate the reason to open the drain. Excellent photo showing the missing dipstick cover to remove.
 
#48 ·
Can anyone help me!! I have a 2002 C240.. I have never had any major problems with it but for some reason I drove 80 miles yesterday and when I got home there was nothing wrong then about 30 minutes later I went outside and it would turn over but not start then about 15 minutes later it started so I went to drive it to town and it only went about 3 miles and then died again then started about 45 minutes later but with the check engine light on.. Checked all of the fuel pump relay switches in the back they seemed hot when they put some engine starter on it it tried to start.. People are telling me it's either the fuel filter, or the CPS, or worst the fuel pump, I live out in the middle of nowhere 60 miles to the nearest town I'm a single mom and this is my only vehicle any suggestions would be very very appreciated!
 
#50 ·
01 C240 oil change, topside, successful, I thought. Then I got an oil too full message and to reduce the amount. Now, however the tube I used to suck the oil out will no longer go down far enough to draw any oil out. The tube bottoms out. Anyone have an explanation? How much trouble am I in?

I use the suction tubing that came with the top sider device, with ice maker tubing at the end for a fit down the dipstick opening. Always worked fine until yesterday.

That fancy oil level check this forum pointed me to varies from 7.8 qts. to 8.3
 
#51 ·
MAF Sensor Cleaning

Hi Guys

Can any of you please assist.

I have a 2006 C220CDI and I'm looking into cleaning the Mass Air Flow sensor.

Please can you advise on what to use to clean this out and if anyone can provide any precautions to be noted when doing so id really appreciate it

Thanks guys.
 
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