Rust on frame behind grill

921 Views 20 Replies 9 Participants Last post by Spearfishin, 15 d ago

Fxstc1995

Discussion Starter · 23 d ago

2011 CTS-V Coupe A6. Has anyone seen this before? This was a leased vehichle that I bought from a guy that bought at auction with 20K miles, I noticed this surface rust while installing a new splitter and considering black spraying the grill. There are no water sources nearby and no leaks at all, the car now has 40K. There is no indication of rust or water leakage anywhere else. Any thoughts what may have caused this? I am thinking maybe a HX installed and removed prior to lease expire? Mostly curious, never know when buying without the meeting the actual previous owner. That being said, what is the best recommended way to treat this?

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1 - 20 of 21 Posts

Fantazma

· #2 · 23 d ago

It is your bumper reinforcement bar. Just spray with some black krylon, scuff it up first.

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Gohawks63

· #3 · 23 d ago

I have some on mine. 2012 A6 coupe with 52K miles.

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Fxstc1995

Discussion Starter · #4 · 23 d ago

Thanks guys! I will do that.

SaskV

· #5 · 23 d ago

Here's a visual for you, the top of the crash bar (arrow) with the bumper cover removed

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Blades1_99

· #6 · 23 d ago

Had it. Took sand paper to surface rust....wiped down, painted with Black Rust-Oleum, never came back.

"Pearl" is a 2011, V Coupe, A6, Recaros, Skyview.

Mods: Airaid - Red filter, Side Swipe, Mamo LS7 Ported TB, ZL1 lid, Fasterproms underhood tank, BMR Catch Can, .... 503whp - 522wtq @ 8 psi boost on 110 Octane
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RobF300

· #7 · 23 d ago

I don’t think it was painted from the factory, they rusted within 1 year

SaskV

· #8 · 22 d ago

RobF300 said:
I don’t think it was painted from the factory, they rusted within 1 year

The impact bar on my 2012 was definitely painted from factory. (photo above)

jr16

· #9 · 22 d ago

Just as stated above, it's normal. I personally plan on swapping to some black grilles and changing the H/E out, so during those procedures, that'll also getting cleaned up with a good scuff n' shoot with some Rustoleum.

Fxstc1995

Discussion Starter · #10 · 22 d ago

Thank you everyone for the comments and pictures, seems like an easy enough fix. I was mainly concerned about what caused the rust since there was none on associated structures, didn't just want to paint over a problem that could recur. Not being the original owner of a previously leased car I thought maybe there had been mods done that were removed prior to turn in, I have not found any evidence of that on bolts for pulleys, injectors, or the other normal indicators. Love the car and runs great!

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ersatz36

· #11 · 22 d ago

I've seen a handful of these cars locally and they all seemed to have this issue, so it seems pretty normal. I just fogged mine with black paint while I was replacing the hx. I'd suspect that whoever the original supplier of this part was didn't do a very good job coating them.

RobF300

· #12 · 22 d ago

SaskV said:
The impact bar on my 2012 was definitely painted from factory. (photo above)

for normal cars left outside they started to rust within the first year, if you bought your car used someone probably painted it which is a normal thing to do if you change out the grills, headlights, add a larger heat exchanger or just wanted it to look better.
shit even my GMC had the same crap- practically bare steel behind the grill that I had to paint with some satin finish black.

SaskV

· #13 · 21 d ago

RobF300 said:
for normal cars left outside they started to rust within the first year, if you bought your car used someone probably painted it which is a normal thing to do if you change out the grills, headlights, add a larger heat exchanger or just wanted it to look better.
shit even my GMC had the same crap- practically bare steel behind the grill that I had to paint with some satin finish black.

I just happen to have my car disassembled at the moment and I can assure you the impact "bar" wears the original factory applied black paint coating. It's likely as durable (or not) as the paint coating on all the rest of the chassis components. I purchased my car "used" with 19,000 miles.

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RobF300

· #14 · 21 d ago

ok

Fxstc1995

Discussion Starter · #15 · 21 d ago

Interesting, thanks for all the inputs. I guess regardless of cause I will take the suggested steps to correct. I'm glad to know that I am not the only one to have encountered this but I have to agree with SaskV that it would have been factory painted the same as the rest of the front end. I can't think of anything that would naturally cause that level of corrosion on a painted surface while having zero corrosion on adjacent surfaces. I am now quite curious to get the bumper off.

Fxstc1995

Discussion Starter · #16 · 21 d ago

You would think I would have better things to consume my thoughts but these are the types of things that keep me up at night, lol. After a bit of thinking and looking at the pictures I posted, the rust is uniform across the entire bar, there are no signs of any bubbling paint or flaking, this is all surface rust that you would get on bare metal. This was originally a Canada sold car, perhaps there were years/models that the bumper bar wasn't painted coated? Maybe an oversight by GM? 2011 V Coupe A6.

RobF300

· #17 · 21 d ago

When I said no paint maybe I should have said insufficient, obviously they have some paint. But my 2011 and my 2014 both had identical surface rust on top and my 2014 was a southern car it’s whole life and neither car has ever seen salt or snow.
that’s why when i was whipping out the paint to paint some insufficiently painted supports behind my GMC grill (a mid west truck) I kinda laughed to myself about it

SaskV

· #18 · 20 d ago

Fxstc1995 said:
You would think I would have better things to consume my thoughts but these are the types of things that keep me up at night, lol. After a bit of thinking and looking at the pictures I posted, the rust is uniform across the entire bar, there are no signs of any bubbling paint or flaking, this is all surface rust that you would get on bare metal. This was originally a Canada sold car, perhaps there were years/models that the bumper bar wasn't painted coated? Maybe an oversight by GM? 2011 V Coupe A6.

AND there's your answer... Eastern Canada has been using liquid deicers on their roadways for decades, while Western Canada is just catching up the last few years. It's absolutely horrible on a winter driven vehicle! Depending on what geographical area of the country it initially resided, and how many winters it was driven, a less than optimally prepped and painted surface could have corroded quick. I don't feel the part left the factory unpainted, was it WELL prepped before paint? probably not. That's my guess.

Fxstc1995

Discussion Starter · #19 · 20 d ago

SaskV said:
AND there's your answer... Eastern Canada has been using liquid deicers on their roadways for decades, while Western Canada is just catching up the last few years. It's absolutely horrible on a winter driven vehicle! Depending on what geographical area of the country it initially resided, and how many winters it was driven, a less than optimally prepped and painted surface could have corroded quick. I don't feel the part left the factory unpainted, was it WELL prepped before paint? probably not. That's my guess.

Thanks again guys, great responses that make good sense! I probably over-complicated a relatively common problem with a simple solution. That's why I love this forum and all the experience everyone contributes.

RobF300

· #20 · 19 d ago

except that cars that have never seen snow or deicer also had the same issue

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