Cut a hole in the bottom?

 

There is already a rectangular cut 1" x 1/4" , however what is the point of a the Bowl design with a single hole... when hold 2 lbs of sands each only in one season.

 

Popr design for sure. It is plastic so it won't really rust or degrade.

Put some flat urethane rally flaps on it?

 

Fill it with foam?

 

I hope the next year GM summer student do a better design job. There are multiple design issue with these mud guards.
i.e. these should have used plastic re-usable rivets/ clips instead of metal T15 screws + washers .
Rear ones has one large aluminum rivet (not serviceable ) not sure what the dum dum designer was thinking.
Also there are gaps about 1/4" +/- where road salt and sands is getting in inside wheel wells
Also extra Fasterners are hidden under these mud guard in rear as well.
Overall too many plastic layers covering another panel -some appears after thought as well - with Lots and I mean Lots of fasterners - excatly the opposite of the lean design philosophy by Munro & Associates.

 

Did you have any more photos?

Was this the front or back or all?

I got mine booked for oil spray next week, so they will need to take those off.

 

Above picture was from front passenger side, however the other ones all had varying amounts of sand collected in them. I ended up DIY undercoating it all, 17+ T15 metal fasteners per each wheel well covers are crazy, but good thing is that most orange cables under driver rear wheel well seems well protected with corrugated orange plastic conduit, bad thing it is a rats nest of wires almost everywhere, and way too much surfaces to cover , also ensure area behind the steps gets treated as well.

 

I appreciate the information. I guess with EV you really only need to spray the wheel wells and the tail gate, inside doors... would be the main spots

The battery shell that's makes the structure of the car is e-coated. Not sure what type exactly.
But I believe the e-coats are extremely corrosion resistant (that's what I heard, so not 100% sure)
So anyways you don't need to spray the frame

Did you drill holes inside the door panel and spray there?

 

I did not treat the battery protection underbelly, I will keep an eye on it after presssure washed every spring and treat with a small spray - only if needed , but looks well protected already - unfortunately did not take a picture of Rear Driver side with actual rat's nest of wires and flex conduits -

Other areas to consider to rust proof are:

• Exposed Black eCoated metal brake lines
• inside/outside of the rear Hitch and
• double-box C Channel front protection metal profiles +
• all the Black eCoated chassis and rear suspensions inside & out +
• Body coloured uni-body box and C channels alike (see pictures)
• Also I opened Frunk bucket and covered the motor parts with a small tarp before spraying.
• Hood and inside of front metal panels -

NOTE: Please Do Not spray Rust proofing oil based on any Rubber / wire / wiring harness / plastic parts. I have used Lanolin based Fuid film(smells for first week) (or similar WoolWax / SufaceShield with less smell ) Also Not recommended to spray on Wire jackets or other plastic/chassis rubber bushing parts as it may swell those parts and reduce their life and hence may void your warranty for such parts.

however I understood it should be safe if accidently sprayed on Rubber peices that are already protecting greased moving parts like CV-Joints and other rubber joints - but who would spray such rubber parts anyway. if accidently sprayed ensure to wipe it clean with clean rag or cover such areas with plastic wrapped and taped in advance.

Note: Aluminum casting where front struts/spring is mounted does not need rust proofing treatments

t

 

I have used an undercoating spray very similar to this :

RODAC Heavy Duty Rust Proofing Undercoating Gun - Professional

Heavy Duty Rust Proofing Gun Undercoating : Amazon.ca: Tools & Home Improvement

a.co

Also 10+ Gallon Air compressor at 60-90 PSI setting passing through cooler and 4 chambers of Air dryer to extract as much moisture as possible
Also boiled water and dipped the undercoating-spray with Fliud Film inside inside a warm bucket of water for 10 minutes to liquify otherwise a light grease consistency of under-coating Lanonin based oil.

Also for DIYers out there here is a good uTube on how to :

 

Fantastic pictures!

 

I am doing mine at krown. That's pretty much what we have year and it's extremely well known.

But I will sure tell the installer the tips you provided and go through the photos.

And yes I was going to compliment the pictures too, you @Ryanthegreat1 beat me to it.

 

Can anyone tell what the kind of sealant used there? Ie silicone based or polyurethane based?

 

Those white beads must be some kind of Urethane based caulk/closed-cell dense foam ( it is not flexible ) and it is almost everywhere in SEV. including two lines inside the bed.

 

Here is a few more odd pictures with the first note worthy is showing those exposed Orange HV Cables that are not protected against gravel form dirt roads hitting them.

I recall at least one users driving on miles of gravel roads had to replace them.
That is just my guess this is the one... the rest are abit more protected by inner wheel well covers... well sort of ... Note that small stones collected inside the Spare tire rim otherwise...

 

Here is a few more odd pictures with the first note worthy is showing those exposed Orange HV Cables that are not protected against gravel form dirt roads hitting them.

I recall at least one users driving on miles of gravel roads had to replace them.
That is just my guess this is the one... the rest are abit more protected by inner wheel well covers... well sort of ... Note that small stones collected inside the Spare tire rim otherwise...
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I believe the same user or a user who is familiar with this incidence put the rest cover on it..cut a small rectangle to fit the for the spare wheel holder. I would probably tapena larger square of a material like tyvk so sand does collect in there over time.

Here is the post.

Thanks for sharing. Well done and well explained. Appreciate you.

https://www.silveradoevforum.com/posts/43994/