C280 Spark Plug Problems.

[wendle10]

Hi can anyone help? I have a 1999 C280 Sport 2.8 V6 Auto. I attempted to change the spark plugs over the Christmas period but to my horror found that there are 12 plugs rather than the anticipated 6. Does anyone know if they are all the same & if the gapping should be 1.1mm all round? Also as it looks quite cramped in there, is there a special tool Mercedes use to get at the plugs as they are a good few inches inside the head? Am I better off taking it to Mercedes & does anyone know what they charge?
Any feedback would be much appreciated.

 

[jberks]

I have changed them in an E240 - basically the same engine - V6 block and twin spark. All I can say is unless you are very enthusiastic, don't bother.

It's a real g.t of a job! They are not accessible (on a bigger E, let alone a C!), you need a UJ, various extension bars, strong fingers and a hell of a lot of patience. I stripped out the air filter and MAS to get better access but even then it was a horrible job. With hindsight, it may be a little easier if you can remove the plastic engine cover but the plugs are still out of the way. Also, the leads are very stiff to put back. They click over the plug and each one took me a couple of minutes to refit, rocking back and forth and pushing as hard as I could - remember, you can't get the leverage. Get one not quite right and you have a subtle misfire that's a bugger to find.
The plugs are replaced every 60k so you need platinum or irridium but NOT copper. I got mine from http://www.sparkplugs.co.uk/ and a set of Irridium plugs cost me a shade over £100. You also need a 10mm plug spanner - got mine from Halfords for around £10.

The dealers charge around £250 for the job and given the work required, if I am ever faced with this again, I'll pay!
Specialists are probably cheaper still so I'd ring around if I were you.

 

[television]

I have changed them in an E240 - basically the same engine - V6 block and twin spark. All I can say is unless you are very enthusiastic, don't bother.

dealers charge around £250 for the job and given the work required, if I am ever faced with this again, I'll pay!
.

Come on this is not like you, what could be more pleasant than standing outside on a nice frosty morning changing your plugs.

Malcolm

 

[jberks]

what could be more pleasant than standing outside on a nice frosty morning changing your plugs.
Malcolm

In the case of an MB V6 amputation comes pretty close. Actually I was considering suggesting the task to the US forces as a way to extract info from prisoners. - "Change those plugs or tell me where Osama is..." They'd find him in no time!

 

[television]

Its not funny really, I have the same engine, I looked at them and looked away. Out of sight and mind. Mines just coming up to 40k

Malcolm

 

[Richard Moakes]

Makes me glad I have a nice simple M103 engine ;-)

 

[television]

Makes me glad I have a nice simple M103 engine ;-)

But think of the saving that we make, we don't buy any plugs.

Malcolm

 

[Richard Moakes]

But think of the saving that we make, we don't buy any plugs.

Malcolm[/QUOTE

Very true ;-)

Only job I have found which I could use for torture is the water pump, evil job :-(

Richard

 

[kth286]

Guys

What a retrograde move that engine was.

History will show what a superb engine the previous 4 valve per cylinder straight 6 (104) motor was.

Same power output, and my last plug change cost £10.97p including VAT for 6 Bosch plugs from Mercedes. (every 18000 miles and easy to replace).

Superb !!!!!!!

Regards

 

[television]

But think of the saving that we make, we don't buy any plugs.

Malcolm[/QUOTE

Very true ;-)

Only job I have found which I could use for torture is the water pump, evil job :-(

Richard

Somehow my enthusiasm works hand in hand with my age, Years ago If I wanted to slip an engine out, I did it, almost looked forward to it.
What did you say, Water pump, whats that!!!!! its like sex, I know that I have heard the word, but I cant remember what you do with it.

Malcolm

 

[wendle10]

Thanks for the advice everyone. I think I will leave them well alone then. It's only because I had the plugs that I wanted to change them. There's no mis-fire. I think I will take them back. Now that thats all sorted what do you make of the next problem?

Chrismas morning was a bit mad in my household. My Grandfather had been suffering from Lung Cancer for about a year & he calapsed on Christmas Morning. Hurrying down the motorway to Taunton, Somerset I was doing rougthly 110mph so as to see him before he passed away. All of which was sadly too late. On the way back home I noticed that the gearbox would take a split second longer to change gear as if it wasn't engaging the next gear in time. (I have the 5 speed auto, non trip kind by the way). It all runs smoothly but 20k driving this car means you can tell when something is up. Do you think it could be low on fluid? This has not been done since I have had the car & im not sure about before that. It has 84k on the clock now & I bought it on 60k. Also is this an easy thing to do or would it be best done on a 4 post ramp?

Any help on this matter would put my mind at rest.

 

[television]

In very cold weather it may have too much oil in it, wait a few days (getting warmer) and see if it is the same

Malcolm

 

[big x]

I'm curious why mercedes went the twin plug route in the first place ?
I changed the plugs on my 1992 BMW 740i V8 at the weekend and it's a doodle...30 minutes or so.The wires slide off really easy by lifting the catch and access is perfect.Anyone could do it.
The latest Bosch super4 plugs (4 electrodes) can last 100k and I've found they don't foul or soot up at all compared to normal plugs on older engines, so I guess most owners may never have to change them.

adam

I have changed them in an E240 - basically the same engine - V6 block and twin spark. All I can say is unless you are very enthusiastic, don't bother.

It's a real g.t of a job! They are not accessible (on a bigger E, let alone a C!), you need a UJ, various extension bars, strong fingers and a hell of a lot of patience. I stripped out the air filter and MAS to get better access but even then it was a horrible job. With hindsight, it may be a little easier if you can remove the plastic engine cover but the plugs are still out of the way. Also, the leads are very stiff to put back. They click over the plug and each one took me a couple of minutes to refit, rocking back and forth and pushing as hard as I could - remember, you can't get the leverage. Get one not quite right and you have a subtle misfire that's a bugger to find.
The plugs are replaced every 60k so you need platinum or irridium but NOT copper. I got mine from http://www.sparkplugs.co.uk/ and a set of Irridium plugs cost me a shade over £100. You also need a 10mm plug spanner - got mine from Halfords for around £10.

The dealers charge around £250 for the job and given the work required, if I am ever faced with this again, I'll pay!
Specialists are probably cheaper still so I'd ring around if I were you.

 

[big x]

http://www.boschautoparts.co.uk/pcPlug4.asp?c=2&d=1

Click on the link "want to know more" for info on how they self clean"

 

[jberks]

I suspect the twin plug idea is primarily to do with emissions. Most of these things are. It always amuses me, Alfa's advertise "Twin Spark" in big shiny letters on the back, MB don't bother mentioning it. I doubt it makes any real performance difference but I suspect starting the combustion in 2 places instead of one has some benefit in terms of burn speed which may have an effect at higher revs. The downside is twice the number of plugs, though few of us keep a car for 120k so its doubtful we ever need to change them more than once. The bit I couldn't get my head round was that they charge over £200 for a set of 12 leads!

 

[wendle10]

Thanks for the info on the Auto Box too. With regards to the Twin spark, I think it just goes to show that Mercedes-Benz are a high quality manufacturer who don't need to brag about what they produce. The quality sells it to me. The C280 will blow most things away at the lights. It doesn’t sit there shouting “Look at me, I’m a performance car!!!” it’s very discreet when you want it to be.