BenzWorld Senior Member
Date registered: Oct 2005
Vehicle: W163 ML320, W220 S500, R230 SL600TT, R170 SLK230, W140 S500, More
Location: America the Beautiful
Mentioned: 3 Post(s)
Quoted: 48 Post(s)
My 2008 GL450 owners manual book that came with the vehicle, says to use NGK PLKR 7A. Also known as NGK 4288...If there's anything I've learned in 20 years of owning Mercedes, it is to use exactly what they came with, not substituting anything else. While some may have good luck using other plugs, it is best to stick with what they used at the factory. I found these plugs for over $11 each on NGK's website, and even as high as $14 each elsewhere but I purchased mine (all eight plugs) for about $70 on Amazon. I always look for the best price when buying parts! I would bet that your owners manual, if you have it, would specify the same plug for your 2009. I haven't changed the plugs yet, as I just received them today, but looking at the engine, it looks pretty simple, each plug has its own coil and they look simple to replace. These NGK PLKR 7A are platinum. I don't believe that platinum plugs need to be gapped, meaning they should have the correct spark plug gap right out of the box.
Last edited by tonylinc; 07-12-2019 at 05:04 AM.