hanli0315

Has anybody replaced their spark plugs?
First, I just found out today that it needs 12 (two per cylinder).
Then I went to AAP website found this
http://shop.advanceautoparts.com/web...1807427167____

It's not cheap, but seems like the right part.
If anyone has done it, please share your experience. Thanks!

MKenM

Just out of curiosity how many miles do you have on your GLK?

venchka

Check the manual.
2010: 8 years/80,000 miles.
2011: 6 years/60,000 miles.

MBRedux

I'm not touching this........

MKenM

Not to worry, I will.

We understand that you are a newbie so there are a couple of things you need to learn.

First, don't tell us to read the manual we want facts and opinions. The manual is not always right.

Second, read a post before you respond. I asked how many miles he had on his vehicle. Can you tell me how many miles he has on his vehicle?

Another tip research your questions by using the search feature in the blue bar to see if your question has already been answered.

Keep trying you'll make it.

venchka

The OP's miles aside, who are we to believe?
The Marketing Speak brochure says that the plugs are good for 100,000 miles.
The 2010 Maintenance Schedule advises changing the plug/coils at 80,000 miles.
The 2011 Maintenance Schedule advises changing the plug/coils at 60,000 miles.
The 2012 Schedule is not available online at this time.
I realize for most of us, even 60k miles is a long way off.
I will follow plug changing inveral discussions in the future.

Wayne
In Time Out in Texas.

hanli0315

Didn't mean to create such an arguement.
I have 60K on my car, I was also confused about the marketing brochure said 100K but the manual said 60k. I just figured take it out to check and have the parts ready, if need replace just replace them.

MKenM

Not a problem sometimes Newbies do things like that. No argument just a little guiding light. The Bosch plug is a great durable product. In other vehicles the Bosch plug lasts for 100K miles. Do you use premium? How has you gas mileage been since the car is new? What kind of driving do you do?

Answers to all of those questions will lead you in the right direction. If you are really curious pull a plug. See if the gap is OK. Is there a lot of carbon build up? Do you smell gas on the plug?

Get the idea? 60K miles IMO is not accurate but your driving habits will help in determining when its the right time. Just my .02 cents.

hanli0315

I used premium all the time. MPG has been around 22-24 ever since I got the car. I do highway about 100 miles a day.

Yes, you are right, I'm gonna just take out one and take a look.

Thanks a lot!

SeaMonkeyGLK350

Okay, here it is 5 yrs later! :-) So now, the 2010 GLK 350 maintenance manual says to change the plugs at 60k miles. That's where I'm at now. Question is, should I also change the coils while I'm in there, or should those last a lot longer?

Thanks!

NYCGLK

You can take a look and see. Mine looked perfectly fine.

bop11

Be careful pulling that plug. Carbon build-up can do wonders on the threads and crossing the threads is easy especially with the plug so far down. A mangled threads is a very expensive proposition on these cars and with the aluminum heads and the deep insertion not to hard to do. It's not like a cast iron head right on top or even a 350 head for the 80's- 90's, with a little contortion to get them in. Either be extremely careful or let someone do it who, if they ruin it, has the ability to fix it at zero cost to you.
By the way my 2010 only has 6 plugs

SeaMonkeyGLK350

Thanks, bop! Yeah, mine only has 6 plugs as well. I will definitely be careful!

chuckmahon

The 2010 GLK 350 has ONE plug per cylinder. 6 plugs total.

Spark plugs changed at 100,000 miles - no need to do sooner unless you clearly have ignition problems.

SeaMonkeyGLK350

I've seen that stated several times in this forum, but the maintenance book states every 60k. So you're saying 100k is what you go by? The engine seems to be running fine.

Thanks!

chuckmahon

100K is the informed decision I made with my service mechanic based on experience and condition of my engine.

Now at almost 110K I understand much better whats vital to service at proscribed intervals (e.g. transmission,engine oil) and what can be deferred or moved "on condition" or extended (e.g. brake fluid based on what the fluid tester indicates).