change them on the M271? Did a search, didn't find anything. How do I remove the motor cover?

 

I'll make some assumtions that this is a C230 Kompressor, Model 203.740, with engine 271.948. This is an inline 4 cylinder 1.8l motor with a supercharger. A supercharger takes power from the engine to compress the intake air. A turbocharger uses exhaust heat to turn a compressor for the intake.

For this motor you need 4 ea Bosch f 6 MPP322 or NGK ILFR60 plugs. Now, if your car has been in the USA the whole time, you should not need these plugs for 100,000 miles. These are the only two plugs approved by Mercedes for this car in the USA. Other plugs may fit, but these are approved.

There are four ignition coils on top of each plug. Be careful, they can shock you. If you have an implanted pacemaker, you should have someone else do this work.

Pull the engine cover straight up, (Germans use two hands, so they don't break it, I guess.) and you can see the "coil packs" in a row on top of the head. Make sure the key is out of the ignition, and if you have keyless GO, move the cards out of range. Remove the primary connector from each coil. Unmount the air pump switchover valve and lay it to the side. Then remove the two screws holding each coil. Carefully remove the coil pack from the top of the spark plug that is under it. Pull straight up.

Now you need a 16mm sparkplug wrench. It is part number 112 589 01 09 00 and costs about $ 60.00 from an online tool shop. (put the number in google to find them.) I don't think you need the fancy swivel head socket to do the job, as any thin wall 16mm spark plug socket should work fine.

Use the tiniest amount of antisieze compound on the plug threads, and tighten in two stages to 28 NM. (The first stage is to 21 NM, let it rest a minute, then apply 28 NM torque to the plug.) I know a lot of mechanics don't do this, but they don't own your aluminium head either.

Now installing the coil pack takes some instruction. Look them over carefully, if there is any discoloration or cracks, it should be replaced. You must now position the spark plug connector in the starting position. You pull out the bottom of the connector so that there is 124mm from the bottom of the sparkplug connector to the bottom of the widest portion of the coil pack. Then put the pack on the plug. Tighten the screws to 8 NM. You don't want it to come loose, or damage the head. Plug the connectors back in, mount the air pump switchover valve back in its holder.

Put a touch of Vaseline on the mounting feet for the engine cover, it will make it so much easier to fit in place.

Now, never disconnect a coil pack with the car running, or short out the wires (it will goof the alarm system.) Don't try to hold the pack above the plug to "see if there is a spark." It is not 1972, and these cars are not your fathers Oldsmobile. The coil requires a 2K ohm load at all times, so never turn the car over when the coil packs are connected, and the plugs are out. For a compression test, you need to remove the packs from the car.

I hope this is helpful. Now if you have a V6 or V8, aren't you lucky, they have two plugs per cylinder. At $ 39.99 each, every 100,000 miles makes more sense.

The 271 engine has a coil for each plug, and there is one plug per cylinder. There are no EHT (extra high tension) cables like a lot of cars that connect the sparkplug to the coil. The sparkplug connector is part of the coil.

Each spark plug when installed and tightened to the specified torque, will be at a slightly higher or lower position due to manufacturing tolerences. To adjust for these differences the connector on the coil pack can move. When you install it, you first pull it out to the 124mm dimension, then as you push it on the plug and tighten the two screws the connector telescopes to provide a precision fit on the plug. Nothing complicated, but if you don't know to pull it out, it might not make good contact with the plug. This could cause poor performance and even damage the coil pack.

 

A picture of the coil pack, dimension 'a' is the 124mm.

 

This is exactly what I was lookin for, thanks.

 

Moviela, damn, good write up. Nice tech notes too. I think I had used this when I did my plugs. Only I went with a one step colder plug because I'm running the Kleeman Pulley on my M111.

Now, to get my butt off the board, and check out why I have freeplay in my steering....

E

 

Great write-up. I wish people like you (who knows DIY) can write up as good as this. Copied and Saved on my files, I know I can use it sometime.

 

Antisieze a must when putting in new plugs?

 

suggested, but not a "must".

 

I was kind of lazy to run to the store to buy it. I never use it in the past.

Anyways, rather than wondering if I don't put it on. I stopped by Auto Zone on the way to work this morning. Got a tube for under $4.

 

I've been doing plugs on mulitple cars all my life. Never used antiseize or ever had a problem getting a plug off. It can't hurt. I do put anti sezire on any nut i take off in the suspension and the wheels esp when i "use" to rotate them

 

My owner's manual (2005 C230 with M271) says 60,000 miles for plug replacement. Is MB trying to get their dealerships some extra cash, or should I not wait for another 40,000 miles?

 

I would check again - the Operator's Manual states to do it every (or at least the first) five years...If you have a 2005, that was built in 2004...this is the year to replace the plugs!

I just replaced mine - and anti-seize I would recommend...as my OEM units squeaked and squeaked as they came out - I backed off a few threads - more compressed air, vacuum...loosen some more...

Just in case - and if some one is reading this that does not know - the engine and cylinder head has to be STONE COLD! As in, let it sit over night, then start the work!

 

Be safe then sorry.. It takes another 15 secs a plug to do it.. just be glad you don't have 12 plugs

 

My MB book says 80,000 miles or 5 year.

2003 C230 sedan.

 

I did a photo by photo how to here

 

i change them every 50k and i just did them again... why wait??? you feel such a difference

 

anti-seize should not be used on modern spark plugs. They are already coated with a metal that prevents seizing. If you do use anti-seize and then install the plugs you can over-torque then (even with a torque wrench) because it lubricates the threads. Look it up if you don't believe me.