Maintenance and advice.
Some of these have been covered and others haven't. 2010 GL550 just turned 120,000 miles. Highway I'm getting between 18.5 to 19 mph. City I'm unsure of as I usually drive highway. .
As always, I appreciate everyone's opinions and answers. Thanks all.
-Chris from St. Louis
-At 120k miles, time for spark plugs. I am mechanical inclined, so I feel this will not be a big deal. My question is, what brand? Part numbers?
-I've seen several Mercedes brand fuel additives. Is this another gimmick that just blows black smoke out the rear and everyone thinks its working when in all reality its just blowing black smoke.
-I know I'm due for air filters. I was going to give the red AEM filters a shot as they claim to have longevity and are NON oil filters. Anyone used them or heard stories about them?
Get an ignition coil so you have a spare ready to go. They seem to have an end of life around 100 to >>> miles.
Forget about the MB fuel whatever. It couldn't hurt to get some PEA containing additive, put it in a partial tank, and leave the truck idling in the garage. I found no harm in leaving it idling for hours. That "hot soaks" the injectors.
No opinion on air filters one way or the other. I always just go with Mann.
I plan to do the pan drop, is the fluid Dex. Or should I use oem fluids.
As always, all comments and concerns welcome.
Th R in the number does not exist in Mercedes specifications and indicates it’s a resistor plug and your car did not come with resistor plugs. Double check with your owners manual, do not trust the USA aftermarket. The photo is NOT the plug being sold.
Just about the only source for the correct plug is a Mercedes dealer.
Last edited by lkchris; Nov 7, 2019 at 07:33 PM.
IkChris, unfortunately my 2010 GL550 did not come with a manual however i did download one from here. Only its for a 2011 gl450.
I planned on ordering from FCP Euro as the reviews on mbworld are above excellent. I'm a huge believer in you get what you pay for. That being said, are there better plugs for replacement than the OEM Bosch?
Should I also replace the coil packs?
***I've lost what I feel like is significant horsepower the last 10k miles***
Again, thanks all for the feedback.
The coils fail or don't. They don't go weak. You ought to have one spare on hand, as they will fail one by one.
You are more likely to be suffering weak fuel, in the form of a failing MAF sensor or dirty fuel injectors.
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You should think of Bosch USA as a totally different company. Their mission is to service USA parts dimestores with ultra cheap parts ... the only way they believe they can compete here.
Your owners manual does not cover your buying USA aftermarket parts ... which anything from Bosch USA is.
This is not the only vehicle where Bosch USA fails to offer correct parts ... same problem for BMW motorcycles, for example.
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You should think of Bosch USA as a totally different company. Their mission is to service USA parts dimestores with ultra cheap parts ... the only way they believe they can compete here.
Your owners manual does not cover your buying USA aftermarket parts ... which anything from Bosch USA is.
This is not the only vehicle where Bosch USA fails to offer correct parts ... same problem for BMW motorcycles, for example.
Bosch lost all my affection when their oil filter (yeah I know, why did I do it) came apart on me in use.
I would think the resistor plugs would be more expensive to manufacture.
I tried to take apart one of the plugs, hoping I could remove the resistor. No luck.
I really wouldn't obsess over the resistor. The spark still jumps the same gap, at the same voltage; it's just that fewer electrons flow in the arc. However, I bet the spark continues for longer. A modest difference either way.









