DIY: Swapping in the diamond or AMG front grille
#1
DIY: Swapping in the diamond or AMG front grille
This is an adaptation of the write-up Krypton did for this forum. I'm going to add some pictures to his steps and also try to clarify some things that confused me while I did it.
I swapped the black diamond grille in on my 2015 C300 4Matic. The whole process should take about two hours. I have a lift, which made it easy to switch from the upper stuff to the fasteners on the underside of the car. But I'll try to write this up with the supposition that the user is working with a jack and jack stands.
1) To get started, I would open the hood and use a T25 Torx screwdriver to remove the five screws, up top. Three are easy to see, and the two on the outside are down about two inches below the rubber seal strip for the hood.
![](https://imageshack.com/a/img922/5434/Lx05il.jpg)
Put the screws in a safe place, and note that the two on the outside are different than the three in the center.
2) Now loosen the front lug nuts with a 17mm socket. If yours were put on by a dealership, there's a good chance that they're massively over-torqued. I believe the spec is 94 ft-lbs, but you can worry about that when you put them back on.
3) Now jack up the front of the car. I'm not going to go through the steps in detail here, or talk to much about safety. But get jack stands under the front jack points.
4) Take both front wheels off. This isn't strictly necessary, but it makes things a lot easier when you're working in the wheel wells.
5) Remove the plastic rivet-type fasteners that hold the wheel well liner in place. There are three that are easily visible on each side. Start with the lowest, and use a small screw driver to pop the center pin up -- then back it out. Then use a screwdriver or little pry bar to remove the serrated piece that does the actual fastening.
![](https://imageshack.com/a/img923/9538/RKgSK2.jpg)
This is what they look like when they're out of the car:
![](https://imageshack.com/a/img923/8343/oAS8s5.jpg)
There is a fourth rivet down underneath the bumper, right along the lower outside edge.
![](https://imageshack.com/a/img923/2639/P7nooK.jpg)
6) Remove the two 10mm screws that hold the bumper cover to the fender. If you peel back the unfastened wheel well liner, you'll be able to see a 10mm screw that is right below the seam between the edge of the bumper cover and the metal of the fender. There is a second screw about 2-1/2" in, a little farther into the darkness. Use a 10mm socket or nut driver to take them out. They look like this:
![](https://imageshack.com/a/img924/6909/uOXyOM.jpg)
And here is what they look like once you've pulled the liner back -- this is looking up into the space forward of the front wheel.
![](https://imageshack.com/a/img923/6560/fK1mUY.jpg)
7) Now get down underneath the car and remove the 9 8mm screws that connect the splash guard to the bumper and the under-engine cover. These are the silver-colored fasteners with integrated washers. Use a nut driver or a ratchet. There are five in the forward row, and four in the row behind that. Once you've removed them all, you can slide out the the splash guard and set it aside.
![](https://imageshack.com/a/img923/6197/W0ezcZ.jpg)
Here's the splash guard once it's out.
![](https://imageshack.com/a/img922/7937/AeIqvh.jpg)
8) At this point, Krypton mentions two screws (one by each front wheel) keeping the bumper attached. I don't know if I missed this or mine were already out. I'm mentioning it in case I'm mis-remembering the steps I went through.
9) The bumper should be completely loose, now. The only thing connecting it to the car are three tabs that slide in where the three top T25 Torx screws went. You should be able to slide those taps straight toward you (toward the front of the car) now and remove the whole bumper assembly.
![](https://imageshack.com/a/img922/4029/vWbur8.jpg)
10) But wait. There is one electrical connection to the bumper, over on the passenger side. If you're holding the bumper and grille assembly right now, you'll note that you're tethered to the car by that connection. First, turn the attachment where it mates with the fiberglass to free up the connector itself. Now you can pry back the black cross piece and slide the gray tab up, which should allow the two connecting plugs to separate. Of course, they've been stuck together a long time, so this is going to take some gentle persuasion. Try to set the bumper/grille assembly on something soft while you do the persuading.
![](https://imageshack.com/a/img922/9546/33KWwg.jpg)
Eventually you will get it apart, and you'll need to find a place for this:
![](https://imageshack.com/a/img924/5346/6mVunw.jpg)
While the front of your beautiful Mercedes now looks like this:
![](https://imageshack.com/a/img923/7913/3waHF6.jpg)
Take breath. You're halfway done. But the tedious and frustrating part is what's next.
11) First, you want to remove the dark gray EPS foam piece that's attached to the backside of the grille. It's held at three points, and you just need to put a finger or a screwdriver in to nudge the plastic retainer over in each of those points to free it up. That's the easy part.
![](https://imageshack.com/a/img922/1171/WnuLL6.jpg)
There is also a rubber cowl that attaches to the backside of the grille that needs to be removed with the patient use of a small screwdriver and/or non-marring tool. This is your first practice for the frustration around the corner. You'll see how Mercedes uses little triangle-profile tabs to hold the rubber cowl in place, and also little plastic retaining pieces to hold the tabs in place. You'll end up trying a few ways to skin this cat, including stretching the rectangle holes the tabs go through. But in the end, you'll get the connecting points snapped loose.
12) Now you'll take what you've learned with the cowl and apply it to the grille itself. If your car is not black, it will be easier to see the (body-color) tabs where they connect to the grille. If your car is black, it'll be a little trickier. But you can put the new grille right above the old one to be able to see where the connections are and how they work. Once again, it's usually a triangle-profile tab and then a curved piece that holds it in place. Work slowly, be patient, and pop them out one at a time. It will make you a little crazy at first, but then you'll get the hang of it. When it seems like a half hour has passed, you'll be surprised to see the old grille suddenly separated.![Smilie](https://mbworld.org/forums/images/smilies/smile.gif)
![](https://imageshack.com/a/img923/6681/8dHhPG.jpg)
13) But you're not done. If you're like me, at least, you still need to move your star and star-holder over to the new grille. To remove that star, you want to gently get a credit card or some other non-marring thing underneath it, and push back the little tabs that hold it to the black cup-shaped thing behind it. Be careful, as it's fairly thin plastic.
![](https://imageshack.com/a/img922/2030/gXt2rS.jpg)
Then rotate the cup counterclockwise to release it. You can only do this once the star has been removed.
![](https://imageshack.com/a/img923/3228/0xgM1T.jpg)
Now it's time to reverse all of this for the re-assembly. Start by rotating the cup into the new grille, then click on the star. Then go through those crazy little fasteners to attach the new grille to the bumper cover piece. The cowl and the foam piece are next. Then re-connect the electrical piece for the bumper, then re-attach the bumper. Boom, you're done.![Smilie](https://mbworld.org/forums/images/smilies/smile.gif)
Note below: I'm typing this from memory, so please comment with corrections if there's something I've got wrong. I've got no ego on this point. Although I like the look of the new grille.
Here's my before and after:
![](https://imageshack.com/a/img923/7503/6321kU.jpg)
Oh, and when you put the wheels back on -- torque those things to 94 ft-lbs, or thereabouts.
I swapped the black diamond grille in on my 2015 C300 4Matic. The whole process should take about two hours. I have a lift, which made it easy to switch from the upper stuff to the fasteners on the underside of the car. But I'll try to write this up with the supposition that the user is working with a jack and jack stands.
1) To get started, I would open the hood and use a T25 Torx screwdriver to remove the five screws, up top. Three are easy to see, and the two on the outside are down about two inches below the rubber seal strip for the hood.
![](https://imageshack.com/a/img922/5434/Lx05il.jpg)
Put the screws in a safe place, and note that the two on the outside are different than the three in the center.
2) Now loosen the front lug nuts with a 17mm socket. If yours were put on by a dealership, there's a good chance that they're massively over-torqued. I believe the spec is 94 ft-lbs, but you can worry about that when you put them back on.
3) Now jack up the front of the car. I'm not going to go through the steps in detail here, or talk to much about safety. But get jack stands under the front jack points.
4) Take both front wheels off. This isn't strictly necessary, but it makes things a lot easier when you're working in the wheel wells.
5) Remove the plastic rivet-type fasteners that hold the wheel well liner in place. There are three that are easily visible on each side. Start with the lowest, and use a small screw driver to pop the center pin up -- then back it out. Then use a screwdriver or little pry bar to remove the serrated piece that does the actual fastening.
![](https://imageshack.com/a/img923/9538/RKgSK2.jpg)
This is what they look like when they're out of the car:
![](https://imageshack.com/a/img923/8343/oAS8s5.jpg)
There is a fourth rivet down underneath the bumper, right along the lower outside edge.
![](https://imageshack.com/a/img923/2639/P7nooK.jpg)
6) Remove the two 10mm screws that hold the bumper cover to the fender. If you peel back the unfastened wheel well liner, you'll be able to see a 10mm screw that is right below the seam between the edge of the bumper cover and the metal of the fender. There is a second screw about 2-1/2" in, a little farther into the darkness. Use a 10mm socket or nut driver to take them out. They look like this:
![](https://imageshack.com/a/img924/6909/uOXyOM.jpg)
And here is what they look like once you've pulled the liner back -- this is looking up into the space forward of the front wheel.
![](https://imageshack.com/a/img923/6560/fK1mUY.jpg)
7) Now get down underneath the car and remove the 9 8mm screws that connect the splash guard to the bumper and the under-engine cover. These are the silver-colored fasteners with integrated washers. Use a nut driver or a ratchet. There are five in the forward row, and four in the row behind that. Once you've removed them all, you can slide out the the splash guard and set it aside.
![](https://imageshack.com/a/img923/6197/W0ezcZ.jpg)
Here's the splash guard once it's out.
![](https://imageshack.com/a/img922/7937/AeIqvh.jpg)
8) At this point, Krypton mentions two screws (one by each front wheel) keeping the bumper attached. I don't know if I missed this or mine were already out. I'm mentioning it in case I'm mis-remembering the steps I went through.
9) The bumper should be completely loose, now. The only thing connecting it to the car are three tabs that slide in where the three top T25 Torx screws went. You should be able to slide those taps straight toward you (toward the front of the car) now and remove the whole bumper assembly.
![](https://imageshack.com/a/img922/4029/vWbur8.jpg)
10) But wait. There is one electrical connection to the bumper, over on the passenger side. If you're holding the bumper and grille assembly right now, you'll note that you're tethered to the car by that connection. First, turn the attachment where it mates with the fiberglass to free up the connector itself. Now you can pry back the black cross piece and slide the gray tab up, which should allow the two connecting plugs to separate. Of course, they've been stuck together a long time, so this is going to take some gentle persuasion. Try to set the bumper/grille assembly on something soft while you do the persuading.
![](https://imageshack.com/a/img922/9546/33KWwg.jpg)
Eventually you will get it apart, and you'll need to find a place for this:
![](https://imageshack.com/a/img924/5346/6mVunw.jpg)
While the front of your beautiful Mercedes now looks like this:
![](https://imageshack.com/a/img923/7913/3waHF6.jpg)
Take breath. You're halfway done. But the tedious and frustrating part is what's next.
11) First, you want to remove the dark gray EPS foam piece that's attached to the backside of the grille. It's held at three points, and you just need to put a finger or a screwdriver in to nudge the plastic retainer over in each of those points to free it up. That's the easy part.
![](https://imageshack.com/a/img922/1171/WnuLL6.jpg)
There is also a rubber cowl that attaches to the backside of the grille that needs to be removed with the patient use of a small screwdriver and/or non-marring tool. This is your first practice for the frustration around the corner. You'll see how Mercedes uses little triangle-profile tabs to hold the rubber cowl in place, and also little plastic retaining pieces to hold the tabs in place. You'll end up trying a few ways to skin this cat, including stretching the rectangle holes the tabs go through. But in the end, you'll get the connecting points snapped loose.
12) Now you'll take what you've learned with the cowl and apply it to the grille itself. If your car is not black, it will be easier to see the (body-color) tabs where they connect to the grille. If your car is black, it'll be a little trickier. But you can put the new grille right above the old one to be able to see where the connections are and how they work. Once again, it's usually a triangle-profile tab and then a curved piece that holds it in place. Work slowly, be patient, and pop them out one at a time. It will make you a little crazy at first, but then you'll get the hang of it. When it seems like a half hour has passed, you'll be surprised to see the old grille suddenly separated.
![Smilie](https://mbworld.org/forums/images/smilies/smile.gif)
![](https://imageshack.com/a/img923/6681/8dHhPG.jpg)
13) But you're not done. If you're like me, at least, you still need to move your star and star-holder over to the new grille. To remove that star, you want to gently get a credit card or some other non-marring thing underneath it, and push back the little tabs that hold it to the black cup-shaped thing behind it. Be careful, as it's fairly thin plastic.
![](https://imageshack.com/a/img922/2030/gXt2rS.jpg)
Then rotate the cup counterclockwise to release it. You can only do this once the star has been removed.
![](https://imageshack.com/a/img923/3228/0xgM1T.jpg)
Now it's time to reverse all of this for the re-assembly. Start by rotating the cup into the new grille, then click on the star. Then go through those crazy little fasteners to attach the new grille to the bumper cover piece. The cowl and the foam piece are next. Then re-connect the electrical piece for the bumper, then re-attach the bumper. Boom, you're done.
![Smilie](https://mbworld.org/forums/images/smilies/smile.gif)
Note below: I'm typing this from memory, so please comment with corrections if there's something I've got wrong. I've got no ego on this point. Although I like the look of the new grille.
Here's my before and after:
![](https://imageshack.com/a/img923/7503/6321kU.jpg)
Oh, and when you put the wheels back on -- torque those things to 94 ft-lbs, or thereabouts.
Last edited by Jack Olsen; 03-13-2018 at 01:29 AM.
The following 5 users liked this post by Jack Olsen:
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#2
Thanks for sharing the post it's very helpful
I was wondering if your car is fitted with Pedestrian Protection - Active Engine Hood, if so I was wondering if you just disconnected the crash pressure sensor in the bumper or did you have to disconnect the battery then disconnect the sensors
Many thanks
I was wondering if your car is fitted with Pedestrian Protection - Active Engine Hood, if so I was wondering if you just disconnected the crash pressure sensor in the bumper or did you have to disconnect the battery then disconnect the sensors
Many thanks
#3
I don't know if the active hood is available in the US? In any case, I think my car has sensors for the (option 258) "Collision Warning System with Active Brake Intervention FCW Stop," but not the full Driver's Assistance Package, which might add other stuff to the bumper or grille (like a Distronic sensor).