Watchie

I installed the GM splash guards on my base model C6 this afternoon. The rears require four holes to be drilled into the inner (plastic) rear fender liner. Unfortunately, the pilot holes I drilled per the instructions did not line up correctly, requiring me to drill different, adjacent holes. Once that was accomplished all went well.

So here is my question. The unused holes are covered up by the splash guards, and the correct holes are of course filled by the provided clips. Do I have anything to worry about with the holes behind the splash guards? They are well hidden, but I am worried regarding water getting behind the fender liner.

Input appreciated.

Boomer111

How about filling them with some black caulk.

Might be able to find some grommets that fit too.

I would want them sealed off, if necessary or not.

Watchie

Black silicone may be the way to go. Unfortunately, no way now to get to the holes from the front as they are covered by the installed guards and to get to them from the back it appears I would have to pull all the interior bits from the coupe area.

ncvette_1FUNRIDE

I wouldn't worry about it.

Watchie

But what if they come back to haunt me in my dreams..?

Boomer111

Nothing to rust after all..

I misread the initial post and thought the holes where in the open.

Might of done the plug job before attaching the guards.

Red08

Since they are hidden behind the splash guards you installed, you might cover up the holes with a piece of duct tape, and then apply a coat of silicone sealer around the edges of the tape. that should take care of it.

Coyote Dave

I would think you could pull the push pins and press in the liner to do some after the fact sealing from behind if you can't sleep. Pain in the butt to remove the whole guard with the 3M tape at this point.

I know some folks also never plan to drive in the rain so it becomes a bit of a mute point.

Been working on mine the last couple evenings...

Good luck.

Watchie

The issue lies with the manner of installation GM directed. They have you line up the guards by hand, drill the holes for the insertion clips, then attach the guard using the applied adhesive strip.

However, what I came to learn is that when you actually apply the guard using the adhesive strip (noting once on, it's on), the holes you drilled when aligning the guard by hand aren't where you need them to be.

I was able to successfully drill new holes using the now affixed guard, but as I noted above, no way to take the guard back off and first fill the old holes.

My suggestion to GM is to revise their guidance and have the installer/owner simply apply the guard using the adhesive tape (very easy to do, then drill the required four holes through the holes already in the guard, insert the clips, and be done. Note this is only an issue with the rear guards. For the front guards you utilize existing holes.

A tight bead of black silicone should keep any major water collection from occurring, the chance of which is already quite limited given the guard is over the holes and the only entry point would be from the top, and then only water splashed on to the inner fend or from washing the inner wheel well.

Watchie

Interesting idea. I'd have to shove some silicone into the "good" hole and hope it got to the bad. I may give that a look.

myfunz

Again nothing to worry about that area is empty and all plastic.

After installing one I also came to the same conclusion as your comment above.
I have commented on this procedure in a past thread the best way to approach the back splash guards is to mount the guard with the double stick tape first contrary to the instructions and use the holes in the splash guard as the guide. Because the inner fender is so pliable it's hard to mount them as instructed, I found mounting first works great.

Sorry for information after the fact, it might help others who are thinking of doing this MOD in the future.

Coyote Dave

Appreciate the heads up on the rear install, doing mine tonight so you guys likely saved me some grief.

Watchie

Myfunz is dead on right. Just make sure you position the rear guards a couple of times to ensure the curve at the bottom is a tight fit. I found they sit about 1/4 inch up from the very bottom of the car for this to happen. Then adhere them, press them in good, and drill away. Using this method it should take you all of five minutes for each side, if that.

Gearhead Jim

When installing my rear guards, I held them in place by hand as per instructions and used a Sharpie to mark the intended hole location. Did it three times and each time the marks were in a different place.

Finally I got really careful about how/where I was holding them, and the marks started coming out the same each time. Drilled the holes and they were correct. But the "mount 'em first" idea sounds better. Be darned sure to get all wax/sealant off the paint (3M Adhesive Remover and then 91% alcohol for me, just quick/firm wipes and then dry), test with a piece of masking tape to be sure the real tape will stick.

For those who worry about the pins, we had a dealer tech who posted that they never drilled the rear holes. Just cleaned the fender very well, used the stock tape, and then cut the heads off the pins and glued them in place for appearance. He said they never had a problem, but that kind of thing is why many of us prefer to work on our own cars.