aficionado

Hi,

At the last tune up the dealer suggested changing the spark plugs. After some exploration I decided to do it myself. It took me about seven hours from start till the clean up; this included three trips to the local parts store (don't ask me why! ). Getting the spark plug boots out was the most painful part because I was afraid of damaging the connecting wires. After taking out the first three boots in about forty-five minutes I got more comfortable and the remaining nine took much less time. Anyways, back to the topic. I took a picture of one of the spark plugs that I replaced and I was curious to see if other members thought that these needed to be replaced Please take a look at the attached picture and let me know what you think.



Thanks!

raymond g-

seems to be somewhat normal but well worn. it's been quite a while since it
was changed, right?

ohlord

How many miles,looks like time.Should not have taken you that long.Did you get the offset 17mm wrench that makes it easy to pry off the boots?Did you torque the plugs and coil packs with the correct ft/lb or newton/meters?did you remove the air cleaner assembly?If it took that long to pull 3 wires are you sure they did not get damaged?
ohlord

aficionado

Thanks for your input. I did some searching online and looking at some of the pictures that's what I also concluded, normal wear. The car has about 75k miles and I am not sure when the previous owner changed the spark plugs.

No, I ended up using a different spark plug wire puller; I did see the wrench but didn't think it would be as useful as this puller. The reason it took me this long was because I was being extra careful to not to damage anything since this was my first time. Yes, I removed the air cleaner assembly on the left side of the engine but the right side was the hard one since that had the ASR assembly and the windshield washer container seemed like it was bolted down pretty good. The first boot took me way too long but once I figured out how it was installed the time for the next ones went down from. Also, I had to make several rounds to the car parts store since I didn't do my complete homework beforehand.

I used both anti-seize and the dielectric grease on each of the spark plugs. I took before and after pictures of most of the stuff for comparison and everything looked OK as far as I could tell. So, I am almost sure that I haven't damaged anything.

You bring up a good point about the pressure. From what I read online I concluded that it wasn't very important. I guess I should have done more research on that . What do you suggest, it it worth going back and fixing? Any suggestion for a tool for that? (considering the very little space in the back left and right corners)

One more thing; you did not say anything about the plug gap. Are the pre-gapped 0.04 good enough?

ohlord

I always check the gap to be sure ,have seen them come out of the box way off.I don't think you need to worry,it's rare.The problem is to tight or to loose on the torque.Consensus is no anti seize ,affects torque settings,and plugs nowadays have special metallic coatings to prevent them from melding into the heads.The 17mm really makes short work of the job,but you won't be doing it for 75000 to 100000 miles again and the horse is out of the barn already.
ohlord

lkchris

This is actually NOT good advice.

Bosch plugs come properly pregapped and in over 20 years have not seen one that was not correct.

OE plugs for your W210 are Platinum and you'll only damage them trying to check the gap.

aficionado

Is it normal for the check engine light to come on after changing the spark plugs? I am guessing that it probably doesn't like the sudden change. Should I go ahead and reset it?

Musikmann

I do not think that is normal, but if the car seems to be running properly, I would re-set it this time (I am guessing it is an electronic glitch). Before re-setting it though, have some place like AutoZone or PepBoys interrogate the car for specific error codes, just to be on the safe side. Hard codes will probably remain after the CEL re-set, but you'll probably lose the soft codes. If the CEL appears again, then I would seek out a diagnostic expert.

ohlord

You can gap an oe plug,with the standard single L shaped arc.Just use a professional gap tool and don't ever contact the center electrode.We constantly regap plugs,sometimes between runs at pac raceway,and at various autocross meets.Not on the mb,but on some of our others.With high output ignitions opening up the gap is common practice.Leave your's stock gap,but once again it's late to check anyway.I've been building race engines for almost 40 years and leave little to chance.Check everything and rest happy in the knowledge.
ohlord

lkchris

American iron hotrod experience has NO relevance to Mercedes engineering.

raymond g-

oh come now, Kent. that statement is quite rediculous. it may have merit,
where needed, but it's quite a reach.

ohlord

If you can read my profile, do you note American HotRod anywhere?I've had my share and built those also,however I have also built,blueprinted and raced Scca sports cars since 1967,which is most likely longer than you have been reading.And yes that includes Mercedes.
ohlord

Quadcammer

one of the stupidest posts I've ever seen.

I don't care what the brand is, its still an internal combustion engine. What makes you think that MB builds an engine any different than anyone else.

you should always verify the plug gaps. I've had both a champion and an NGK that were both gapped at least .012 off what they should have been, straight out of the box.

Mercedes benz has not reinvented the wheel with respect to drivetrains, so why not keep the snobbery out of it.