I was a Mercedes mechanic. I have a 1998 E320 wagon and changed the plugs according to the schedule on page 33, Spark Plug Intervals, in the Service Booklet: At aproximately every 100,000 miles or 4 years. There are 12 of them, they are platinum and cost about $150. It took me a couple of hours and I found it easier to remove the coils also.
Standard spark plugs, 50000 miles. Platinum tip spark plugs, 100000 miles.
120000 miles with original iridium plugs.
How many miles should I have before I change my spark plugs
when do you change spark plugs
100,000 miles according to the factoryspec.
50,000 miles.
100,000 miles.
Recommended change is 100,000 miles
Change the plugs at 100,000 miles or earlier if the engine is not performing as it should.
air filter every 20,000 miles, i change spark plugs once a year
The manufacturer recommends that the spark plugs are changed every 30,000 miles. Many individuals have experienced a much longer life for the spark plugs.
platinum plugs 75,000 miles. resistor plugs 30,000.