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2002 chevy trailblazer_ls
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Discussion Starter · #1 ·
It's some undercarraige rust, probably a result of my dad getting lazy in his old age and not washing the undercarraige after a winter and getting some harsh road salt ware and tare.

Anyways, here is the images, I don't think it's too bad at the moment. I'm more concerned about more rust down the road.

Here's some pictures.







thanks in advance for the advice and/or help.
 

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2002 chevy trailblazer_lt
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I have a ton of undercarriage rust too. I doubt the previous owner(s) took the time to wash the undercarriage on mine. Anyone in the "salt belt" would look similar. It looks a little worse than mine but I wouldn't be concerned, it's mostly cosmetic. Keep in mind your TB could be 8 years old :eek:

Just know that when you have to work on anything under there it's going to be a pain in the ass:hissy:, and I mean it. PBlaster will be your best friend
 

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2008 chevy
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You could do a cleaning; maybe a light sanding, and then apply undercoating. I always undercoat a new car because of the salt and weather conditions. In years time you will come to appreciate it as it will fend off a tremendous amount of surface rust.

Other than that, you should not have any issues at the moment (like rust thru) because gm has made great strides in making rust resistant metal surfaces from the factory. It doesn't mean that your car won't rust (especially in sea level climates), but it will take a very prolonged period before you should see rust thru.

Just remember on your next new car purchase, that undercoating can be a valued friend.
 

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Discussion Starter · #5 ·
Do NOT undercoat your truck, it will cause more problems than it's worth
there any particular reason?

i was thinking of applying some of this stuff my dad has called "Rust Converter" It turns rust into black primer paint. I figured I would do that for the next week or so, then go in and sand off the primer to see how it looks.

It's not my TrailBlazer currently but my dad has talked about selling it to me, so it's probably easier for me to fix this now anyways lol. :undecided
 

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Undercoating plugs all the small holes that are used to drain water. The undercoating will eventually flake/chip/peel and then salt will get suck in those areas causing worst rusting than without it.

Metals used for frames are meant to have cosmetic rust-there is nothing wrong with it besides the way it looks. The metal shouldn't ever rust to where it's an actual problem.

I wouldn't even bother with the rust/primer paint on the frame.

Undercoating is just something dealers do to rip you off- don't fall for it.
 

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^Sorry, but I disagree with that. First of all, there isn't enough of a solid consistency to rubberized undercoating that could plug up a drain cavity. The worst that undercoating could do is provide a bit of aggravation to mechanics if they have to do extensive work under the chassis.

Undercoating, applied correctly, also will not chip off. It depends alot on the cleanliness of your chassis. If you have a underbody with a lot of road grime, surface rusting or oily spots, then you will have some areas where the coating will peel. That is one of the reasons why it is very beneficial to undercoat a new car as soon as possible.

Not for anything, with the advent of galvanized metal and better quality of manufacturing, you won't see many dealers or aftermarket shops that offer undercoating services. However, I can definitely say from experience, that having undercoating will pay dividends in preventing underbody rusting, even in the most challenging winter and salt laden climates.
 

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Discussion Starter · #8 ·
Do you guys think I should just try to take it off with a steel brush or something to see how bad it's rusted? To me it looks like it's just surface rust and what doesn't come off with a brush will probably be taken care of by the Rust Converter. We've used it in the past and it has worked well on rust, not only to stop it but to keep it from rusting over again as far as I've seen.

Sounds like something I should try first. :undecided
 

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I wouldn't go to a great extent in sanding the underbody. You could check one of the bad spots underneath to see if there is a lot of rust or the potential of rust thru. You can use a brush or just a piece of medium grade sand paper. For the most part, you shouldn't have issues with rust thru.

I forgot to mention. Por15 is an excellent product to apply over rust, if in fact you have a lot of surface rusting where the undercoat could possibly peel. Beware: Por15 is a BEAR of an application process for large areas. If you think you're going to have the truck for awhile, then you could try to scope out one or two body shops that offer undercoating services (good luck...a little rare these days) and get their opinion.

But for now, I'd concentrate on keeping the underbody clean with occasional underbody flush washes that some car wash places offer.
 

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Discussion Starter · #10 ·
I wouldn't go to a great extent in sanding the underbody. You could check one of the bad spots underneath to see if there is a lot of rust or the potential of rust thru. You can use a brush or just a piece of medium grade sand paper. For the most part, you shouldn't have issues with rust thru.

I forgot to mention. Por15 is an excellent product to apply over rust, if in fact you have a lot of surface rusting where the undercoat could possibly peel. Beware: Por15 is a BEAR of an application process for large areas. If you think you're going to have the truck for awhile, then you could try to scope out one or two body shops that offer undercoating services (good luck...a little rare these days) and get their opinion.

But for now, I'd concentrate on keeping the underbody clean with occasional underbody flush washes that some car wash places offer.
yea, thanks for the advice man. I'm going to go under it again tomorrow to check if the rust looks extremely bad or not, when it gets wet it drips rust and left some nice stains on the road in front of my house but I'm not sure if heavier rust would do that or not:confused:

for now, I'll make sure it stays clean from anything that could damage/cause more rust to come up.

Bonus to all this: Will show my dad how willing I am to take care of it = more incentive to sell it to me:raspberry
 

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2003 chevy trailblazer_ls
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Any harm in hitting the rust spots with a wire brush and then spraying a little flat black Rustoleum to make the frame look a little better? The frame is really visible from the side.
 

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Nah, I was thinking of doing this same thing myself as I have quite a bit of frame rust too.
 

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Used motor oil in a sprayer can't be beat. As mentioned POR15 (others the same) works great, but is fairly expensive. If you get it on your skin, expect it to stay there for a week as it stains. It doesn't have any UV protection, fine for the frame but anywhere it gets direct sunlight it needs a topcoat to keep it from turning gray and flaking.
There are places that do undercoating, the best type is the stuff that is like a light tar and never hardens, it won't trap water like the stuff in a can. A wire wheel or drum on a grinder will take the rust right off.

Oil enamel will cover right over light rust and last longer than the vehicle, I'd suggest Sherwin Williams. Might have a hard time getting oil enamel now with the tree huggers trying to do away with it.
 
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