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I have a m272 engine (e350, 2008) and was looking to replace my plugs. When I took out the old plug, I noticed some engine oil on the thread of the plug. The ceramics and the tips were dry. And the old plugs looked relatively new.
my car has 67k miles and the plugs didnt appear to be the original ones. I am replacing with Denso Iridium power.
two questions: 1) what could be the cause of oil on the threads? 2) will the Denso plugs improve performance over Bosch double platinum?
I read another thread on w211 with similar symptoms that was due to Cap. https://mbworld.org/forums/e-class-w212/724496-spark-plug-oily-threads.html. Could mine have the same problem?
I changed the spark plugs last month and I had oil on one of them. But as the head looked normal I rest easy that someone has spilled a little oil when adding oil to the engine.
On my Subaru i had to remove engine head to replace some gaskets when I found oil on all spark plugs
Thanks for the reply...but this is getting more interesting.
Please see photos of the plugs that I pulled out.
They seem to have oil on the threads, but nothing on the points. As a matter of fact, they all look pretty clean (so, I am kicking myself for changing these).
You will notice considerable amount of oil on the sleeve (which I used to store them after they were pulled out).
But I am now getting CEL.
Codes:
P2004
P0304
P0354
As I was changing the plugs for cylinder #4, I realized the ignition coil was broken at the connection point.
See pictures below....
So, I replaced the #4 direct ignition coil with a new Delphi ignition coil.
Yet the codes didn't disappear and the car still shakes (which explains the misfire on #4, code P0304 and P0354).
What I don't understand is code P2004.
I didn't touch the intake manifold - why would Intake Manifold Runner Control be stuck?!!
What does this have to do with the ignition coil?
To add, I also changed my serpentine belt, the tensioner and idler pulleys. Although, they looked pretty good.
I just bought the car, so wanted to do some preventative work...oh well, now I might have to take it to the shop. :-(
Replaced my ignition coil with a new one. The shakiness went away. After driving 20 miles, the CEL gone too. All seems well. Drives better now than it did before installing new plugs.
Contemplating to clean the air intake. Also, I want to use the CRC Valve cleaner to get things all in factory shape.
Any other items to consider?
I want more responsiveness and longevity.
When putting plugs into alloy head its normal to use a little oil on the threads so they dont seize in, so the next time you need to take them out they dont bind up destroying the thread in the head, looks to be a normal amount of oil to me for this procedure, its just darkened from the constant heat, doesnt look that bad as the plugs are not coated in oil, if the covers were leaking they would have oil wherever the coil pack does not cover, like where the ceramic meets the thread.
The plugs used in these cars are good for 100,000ks about 60,000 miles and can generally last a lot longer depending on the way the car is driven, I generally change the coil packs at the same time as the plugs as the life expectancy of a coil pack is about the same as the plugs, they will do a lot longer but at a reduced capacity.
Last edited by prktkljokr; 01-03-2021 at 05:00 AM.
Replaced my ignition coil with a new one. The shakiness went away. After driving 20 miles, the CEL gone too. All seems well. Drives better now than it did before installing new plugs.
Chasing a shake myself. No misfire codes. How did you determine it was a solitary coil?
Chasing a shake myself. No misfire codes. How did you determine it was a solitary coil?
On mine, the connector was broken. (See photos). Not sure if yours is same. Perhaps you could use injector cleaners and see if they help. Some swear by efficacy of Red Line fuel system cleaner. It might be worth a try.
For ICMs, 3 things need to work in unison: fire, fuel and air.
For the air intake, check the breather cover and the oil separator underneath it. If you replace the oil separator, note that it's reverse threaded. Seems to be coming up a lot lately. Had to replace the intake on my other car when I got the code. The oil gets into the intake and gums up the flaps so they don't really move. I tried to move the lever on the old intake and it was hard to do by hand and didn't bounce back afterwards like the new one. There's a reason FCPeuro sells a kit with all the replacement parts, you could probably mail order the parts cheaper directly from an MB dealer, but then you wouldn't have the lifetime warranty from fcp. And if your intake is bad, replace the manifold, if the lever or rods are broken, while there are kits on eBay to fix those, eventually the plastic flaps break and fall into the engine causing damage.
12-29-2020, 12:16 AM
Gets more interesting...
