tmise

Is it true you have to remove motor mount bolt and jack up the engine to get to the rear spark plugs??

Rudeney

No, you can replace them from the top. The rear (#3 and #6) plugs can be "knuckle busters" though.

johny1989

and that must be done every 60 000 km?

Rudeney

According to the service manual, it's every 91K miles or 5 years, which ever comes first. If you don't have the service manual, you can go to MBUSA.COM - Owners (or maybe your local MBZ site) and download a copy.

GezaBMX

Rodney, related to spark plugs, I wanted to ask you something. When I get to the point where I should change my plugs I was thinking of churning out the extra money and getting all 12 NGK Iridium plugs. Would this make any difference what so ever? Or what would be a good spar plug for the M112 2.6 ?

Rudeney

Personally, I just use the OEM Bosch platinum plugs, but the iridium should last longer.

GezaBMX

But would it make a change my mpg? cause they are advertised to do so and also to improve acceleration.

Wodeshed

I replaced my plugs with Bosch Iridium because they were on sale for the same price as the platinum. My fuel economy has actually declined by 1 mpg according to my trip computer. It might just be that I'm gunning it more, though.

Rudeney

I really don't believe that spark plugs can make even a 1 MPG difference. The difference in material is mostly about longevity and not "better spark".