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My wife's 2011 GLK350 shakes when you put it into gear. The amount changes from almost nothing to somewhat aggressive. Its fine when driven - the issue only occurs when idling in gear and stopped. Thought it might be a motor mount, but the simple power brake test didn't suggest it was an issue.
A buddy experienced with MB thought it might be a coil pack going bad. I tried my readers, but they wouldn't connect (a separate curiosity). I took it to Advance Auto and they found the following codes (also see attached).
C1122
C1132
C3208
0521-00
Internet searches resulted in faults for the first two codes related to the Airmatic system, which it does not have. I can't find anything on the final two.
So....
1) Any feedback on the codes?
2) Thoughts on what to check on the shaking when it goes into gear?
3) Thoughts on my reader not working on this car. I checked it on my 2020 F150 and they both worked fine.
Thanks for any helpful feedback anyone can provide!
The symptoms sure sound like the classic bad motor mounts. FWIW you can feel it when driving along though you may not recognize it as a problem until after you replace the mounts (at which time you realize that EVERYTHING is quieter). Basically, with good mounts you should barely be able to tell if the starter engaged or the engine started. That's a big difference from a car with worn mounts.
I did a little video on the before / after, including a video of how much the engine shakes / moves with old and new mounts. Might help you determine that is what the problem is (or not)...
Fortunately, we have a good service history. Looks like they were last replaced in 2015 at the 60k mile check. They have note been replaced since. Seems like a good place to start!
We’ve had the problem with for a while, so I’m not thinking bad gas, but injector cleaners would be a good idea.
There are a couple good videos out there on the process. I started to make one, but realized that it wasn't going to be any better than the existing videos, so I just made a few "supplemental videos" on the process. Just click on my channel from the video I posted above, and you should be able to find them easily (one on making the special tool for the top bolt, one on adding a (much-needed, IMHO) heat shield to the motor mount (very necessary as they live about 1" below the exhaust manifolds).
If you have a RWD version, the task really isn't too dramatic (a couple hours IIRC). A 4Matic model is a (very) different story. I'm pretty quick, but it took me about 10 hours, and involved pulling the exhaust, both axles and a whole lot of other stuff. There's a video by a guy doing the job on an outside lift that's as good as you're going to get. He was so spot-on in his process that there wasn't anything I was going to add (other than the two things mentioned above).
I found the video I mentioned (for the 4Matic). There are other shorter videos on the RWD option...
If it’s been awhile since plugs get new plug boots at the same time . I was running great, I had the plugs done and no boots, they broke and I was running on 4 cylinders when I picked it up . FCP euro is a good place to get the proper parts . If plugs are old and coils old, diagnose coils first with the old plugs in place . But maybe it’s the motor mounts !
Please purchase the complete coil, plugs and manifold gasket service kit for this job. I worked as an ignition mechanic through engineering school so I am reasonably capable in changing plugs. Also, go ahead and purchase the thin-wall spark plug socket as this is required. After doing this job four times, the quickest I could do this job was approximately six hours.
For those that have been kind enough to provide advice, a few updates.
I changed the plugs and the crankshaft position sensor with no change. I know at least two people said to change the coils, but I have not done that yet. A local guy that knows Benzes well didn't think they needed done. Of course, he could be wrong.
At this point, I think its time for it to go to a shop. Will provide the resolution when I learn what it is.
Update for all that assisted. Not surprisingly, the general comments were correct. Bad motor mounts. The garage recommended replacing the transmission mount, also, for alignment. I agreed. $1700 + tax. According to our mechanic daughter, the job is 7.5 flag hours. All in, it seems like a fair price. This is not a dealership, but a local shop known for excellent work on European cars. I’ve used them before and like their work.
Are you located in Kansas City? I gave my daughter my 96 SL and we are trying to locate a quality local shop.
Good catch! I am in KC. Is she on the KS or MO side? If KS side, I strongly recommend European Motor Sports in Merriam. They are on the I-35 frontage road on the west side between 67th and 75th streets. Wonderful folks. Great prices for being Benz work. I just dropped off our GL63 AMG last night for a check.
If she is on the MO side, there is a place at 21st and Southwest Boulevard in KCMO that specializes in German cars. I’ve never used them, but they have been there for years. And she can go across the street to Manny’s for great Mexican food.
Let me know who she decides to use! If she goes to European Motor Sports, have her tell them that I recommended them. Randy Ritchie, but they would know me as the “Guy with the GLK350 and GL63 AMG whose buddy has the E55 AMG”. Best of luck!
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Best of luck!
