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Chevy Silverado and GMC Sierra Undercarriage Rust

208 messages,  Last post on May 05, 2013 at 10:09 PM

You are in the Chevrolet Silverado & GMC Sierra Forum.

What is this discussion about? Chevrolet Silverado 1500, GMC Sierra 1500, Chevrolet Silverado 2500, Truck

Messages Page 2 of 22

#3 of 208 Re: 2008 GMC 1500 Undercarriage Rust [blurry25] by bensierra

May 22, 2009 (7:04 pm)

Replying to: blurry25 (Apr 15, 2008 11:26 pm)
My dad purchased a 2008 Sierra 2500 HD last year and asked me to rustproof the frame last fall. I went to my local NAPA store and bought a 5 gal.Rustproofing Undercoat...can remember the brand but I'll check. We put it on the hoist and I noticed the same thing as you. Control arms and rear end were starting to rust. I undercoated the complete frame in and out without any misses. I used about half the pail. I also did doors, rockers, box sides etc....Here's were it gets interesting, 2 months down the road he stopped at the local carwash to clean the winter salt of the truck. The factory undercoating was peeling off like you wouldn't believe!!! The rustproofing totally destroyed the SOFT, STICKY factory undercoating. We are currently trying to clean that stuff off. Never seen anything this hard to clean in my 12 years of Auto Body Repair. Pressure wash, degreased, scrape off, wire brush, degrease again, pressure wash and finally sand blast to finish it all off before epoxy/paint. Nightmare!!!! Wondering if anyone else had or heard of this happening to someone??

#4 of 208 for the frame by ntsmith69

May 30, 2009 (10:19 am)

i am in autobody as well. and what i found that exp on frames and the under carrage is to clean it as best as you can. then use rust converter on the whole area thats needs to be painted. after that dries spay an etch primer on it. you can buy this in cans called ONE STEP self etching primer. this will help bond the new paint to the frame. i have done this to many vehicles and never had a problem. even on the factory coating just add the etch primer and you should not have a problem. it is all in cans so no need of spray guns. and for the top coating i use rock guard in cans. the paintble type . i found the other ones do not harden as much and if you want to touch it up down the road it is easier. but spraying black paint over it will just come off and is just for looks till you get out of the garage.

#5 of 208 Re: for the frame [ntsmith69] by bensierra

Jun 06, 2009 (5:27 am)

Replying to: ntsmith69 (May 30, 2009 10:19 am)
The thing is that rust converter needs rust to work. When you peeled the soft coating off where it hadn't peel yet, the frame was clean bare steel. The rust proofing had melted the factory even softer than it was.Check the new generation GM and no paint or primer will stick on that frame undercoating. You can't blast it or sand it. Stick your fingernail in it and you'll scrape it down to bare metal. It's almost like a grease.

#6 of 208 Re: 2008 GMC 1500 Undercarriage Rust [blurry25] by kendonhank

Sep 17, 2009 (12:45 pm)

Replying to: blurry25 (Apr 15, 2008 11:26 pm)
I am suing GM for this right now. Case goes to court in two weeks.
 
I have a 2005 Silverado 2500 and the entire undercarriage is corroded. Started to get bad after about a year. I live in coastal FL.
 
I have deposed the GM corrosion engineer who developed the spec for the wax undercoating. GM does not apply this coat. It's suppliers do, and some parts are uncoated. He says its for cosmetic protection only and only designed to last a year in the worst environments (GM designs its coating for what it calls the 95th percentile of environments). After that, GM expects the coating to flake off and the vehicle to corrode.
 
GM refuses to cover undercarriage corrosion because they say it was caused by the environment. Duh. All corrosion is caused by the environment.
 
GM also says that their bumper to bumper warranty doesn't cover undercarriage corrosion, only sheet metal. This is not true. The bumper to bumper warranty covers everything except that which is not specially excluded, and there is no exclusion for the undercarriage. There is an exclsuion for corosion caused by airborne fallout, but GM is claiming that salt and even rain count as airborne fallout.
 
Note that GM added a further exclusion for sea air and road salt to its 2007 warranty. It shows they know their vulnerability.
 
GM should repair your vehicle or give you a new one under the warranty, but they won't. That business with the black paint is nonsense. The dealer made it up. Either that or GM has really stepped in it.
 
Can you get me the number of that TSP.
 
Also, can you tell me where you live? State and proximity to salt water. Do they use road salt. What is the extent of the corrosion.
 
You may be able to get relief based on the outcome of my case. I'm thinking it might even develop into a class action.
 
I believe GM is misleading the public about its corrosion vulnerabilty and warranty.

#7 of 208 M undercarriage corrosion by kendonhank

Sep 17, 2009 (12:50 pm)

I have a 2005 Silverado 2500 and the entire undercarriage is corroded. Started to get bad after about a year. I live in coastal FL.
 
I am suing GM for this right now. Case goes to court in two weeks.
 
I have deposed the GM corrosion engineer who developed the spec for the wax undercoating. GM does not apply this coat. It's suppliers do, and some parts are uncoated. He says its for cosmetic protection only and only designed to last a year in the worst environments (GM designs its coating for what it calls the 95th percentile of environments). After that, GM expects the coating to flake off and the vehicle to corrode.
 
GM refuses to cover undercarriage corrosion because they say it was caused by the environment. Duh. All corrosion is caused by the environment.
 
GM also says that their bumper to bumper warranty doesn't cover undercarriage corrosion, only sheet metal. This is not true. The bumper to bumper warranty covers everything except that which is not specially excluded, and there is no exclusion for the undercarriage. There is an exclsuion for corosion caused by airborne fallout, but GM is claiming that salt and even rain count as airborne fallout.
 
Note that GM added a further exclusion for sea air and road salt to its 2007 warranty. It shows they know their vulnerability.
 
I believe GM is misleading the public about its corrosion vulnerabilty and warranty.
 
Let me know if you are having corrosion problems with your GM vehicle. Together, we can hold GM accountable.

#8 of 208 frame corrosion by x_silverado_x

Jun 29, 2009 (5:09 pm)

looking at my frame last weekend i noticed the wax peeling off rusting members from stem to stern.
 
warranty service doesn't seem like a likely option - any ideas?
 
(nbs1500wt, 2008)

#9 of 208 Re: frame corrosion [x_silverado_x] by mram50

Jun 30, 2009 (10:53 am)

Replying to: x_silverado_x (Jun 29, 2009 5:09 pm)
Rust doesn't go away..it just keeps creeping in, but on the frame, unless you live in a high road salt area it shouldn't be a major problem, but if it gets real bad you might consider sand blasting it, painting to cover the pitting or if its REAL bad welding some new steel in there, but frames are generally pretty darn strong and can withstand quite a bit of rust..
Sorry about the extra post I had to delete.. I'm new here..just trying to figure out how the boards work.

#10 of 208 Re: frame corrosion [x_silverado_x] by kendonhank

Sep 17, 2009 (11:36 am)

Replying to: x_silverado_x (Jun 29, 2009 5:09 pm)
Hi,
 
I am currently suing GM right now for this very problem. I live in coastal FL and have extensive corrosion throught the undercarriage. GM refused to cover under the warranty because they say it was caused by the environment. Of course it was. All corrosion is caused by the environment.
 
FYI. I have deposed the senior GM manager from Michigan who developed the coating spec for the undercarriage wax coating. He says it was only designed to last and protect the vehicle for a year in the most hostile environments (the 95th percentile as they call it), and that GM fully expects the coating to fail and the vehicle to begin corroding after a year.
 
GM added an exclusion for corrosion due to sea air and road salt in the 2007 warranty. I have a 2005, which does not have this exclusion (they clearly added it because they knew their vehicles were vulnerable). Yet they still will not cover it, claiming that there is an exclusion for airborne fallout (they consider salt in the air and even water in the air to be airborne fallout, though it does not say this in the warranty).
 
The warranty is a sham and I believe I will win in court two weeks from now.
 
Can you give me more info about your vehicle. My action may help you.

#11 of 208 Re: frame corrosion [kendonhank] by x_silverado_x

Sep 17, 2009 (12:54 pm)

Replying to: kendonhank (Sep 17, 2009 11:36 am)
I have a nbs1500wt 2007 model year. Took it to the dealer, they photographed it and said they would send it into GM > that was months ago and I have yet to get a reply.
 
 

#12 of 208 Re: frame corrosion [kendonhank] by mram50

Sep 18, 2009 (9:59 am)

Replying to: kendonhank (Sep 17, 2009 11:36 am)
Silly in the extreme isn't it?
I worked as a body repair person for quite some time and one was a slap it together joint where we "fixed" vehicles being sold, resold and resold again by used car lots. Many were GM models full of rust and quite often BIG rust holes were covered with fiberglass and nothing more..the first big bump and your car suddenly has a gaping hole in it.
While this is not the same as a new vehicle it just shows that the auto industry in their zeal to sell more and more new cars and trucks build them to last as short a period as possible. Remember, GM invented "planned obsolescence" with the infamous Corvaire. Don't let them forget that period of GM's history in court. It appears that they have changed nothing and it's why GM needed a massive bailout..again.

Messages Page 2 of 22

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