ragu

I bought a 2001 c240 with 100k miles. I bought it at an lease return auction and do not know the history. I was wanting to change the plugs, but when I pulled out the first one, it looked pretty clean. It is a bosh platinum plug fr8dpp33 and has just a little fouling. The needle like electrode is clean. I was expecting to see it worn down or some fouling. I am thinking I should just leave it in.????

raymond g-

http://www.dansmc.com/Spark_Plugs/Sp...s_catalog.html

the above photo chart will still be useful even if you're using platinum or
other space age exotics. if the gap is still within spec, or, you can adjust
to spec, then no need to replace the plug.

sirenebekim

aw dude get the denso iridiums you will never ever regret it... I changed mine out and it felt like a new c!

ragu

I think I will just change them. At least I will know what and when they were put in. Thanks for the help. I am new to mb and not sure about wrenching it.

yeuchau

maybe just change every 20k then u'll be good

mleskovar

The recommended sparkplug change interval is 100K miles. Yes, they burn very clean, even at 100K miles they should look good. If you use the recommended plug again you can expect 100K miles before needing another change. No reason to take a chance with any other plug.

GDawgC220

True, the manual states that they are good for 100k but some people who have changed plugs before 100k have had fouled plugs, etc. I recently changed my parents ML430 spark plugs and some of them were fouled, slight oil on threads and some were beginning to get discolored. After finishing up (16 damn spark plugs is a PITA!), started her up and it purred much better than before. Revving it had a deep growl to it, not a whining noise the engine made prior to changing the plugs. Acceleration was smoother, pick up was better, overall just better than before.

Also the longer you leave it in, the more risk you run of having them seize in there. Some of the plugs I took off were hard enough at 93k miles. Some who have changed before that had plugs break on them while trying to remove because they were seized.

Its cheap insurance to keep the engine performing up to par. I'm sure the plugs will run fine at 100k but trying to get them out and replacing them may be a pain

C43AMG

+ 1

sirenebekim

its easy just follow the instructions for install found on the w203 forum

search for "Plug install"

mleskovar

Then there is something wrong with the engine that needs to be addressed beyond just changing plugs. Plugs don't foul on their own (if they are the correct heat range). The only wear involved in a plug is the electrode and modern engine management and no lead gas reduce that wear to almost nothing. I had no trouble removing the plugs at 100K miles (I still added anti seize with the new ones though ) Every car manufacturer is extending maintenance intervals with new technology and cars are lasting longer than ever but old habits die slowly.......to each his own.

ragu

Just finished changing the plugs 2.5 hours. Everything was going just fine until I was down to the last three on the driver side rear. There is not a whole lot of clearance to get in there. During the removal of the plug wire I put a little too much wrench on it and bam it popped off. I thought everything was ok until I could not get the socket on the plug. Then I realized that the ceramic top to the plug was inside the wire boot.

I got a mirror and could see that some of the ceramic had fallen off and was wedged between the plug and the side wall not allowing a socket to go over it. It took about an hour and a half of fishing it with a coat hanger and moving it just enough to get it out of the way and allow the socket to catch. I crushed what was left in there while unscrewing the plug and paused about every four turns and vacuumed it out. A little nerve racking but everything turned out ok.

I was able to get it done, thanks to the help of the forum members posting. Recommend using a magnetic spark plug socket. It worked like a charm and I don't think I could have done it without one. Also, using the open end wrench to help take the wires off was a good tip.

I ended up putting in the Bosh 2 platinum.

Don't have a better pic of the nightmare.

GDawgC220

Nice! Feels good to have done some maintenance on your own, doesn't it?

btw, is that oil on the spark thread?

ragu

Yes, a light film was on the plug threads. I also have some oil build up from the valve covers. Do you think that some of this may be leaking down or worse?