Is undercoating worth it on newer GM vehicles?

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I do it for myself and friends- it's a lot of work. To me undercoating means rubberized undercoat which is a waste of time. Anti corrosion spray is underbody and inside body panels- I drill a few holes for access to the rockers. For the price of a new vehicle and I tend to hold on to them- I do it and clean the drain holes. Every year is too much- 5 gallons of No drip here is $200.
 
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With fluid film or other light oil based rust proofing product, like Krown or Rust Check, there is no such thing as a touch up. They need to be sprayed all the same every year if you want the full benefit. It’s because they get washed off during winter in most areas exposed to water. Inside cavities don’t need to be sprayed as often though.
I have had a couple of fender benders in my cars over the years and Crown would always do a free touch up on the new parts. I normally get the cars done every two years.
 
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Get them undercoated !
I have lived and driven in the rust belt my entire life, always undercoated my cars .
i have never replaced a brake line, gas line or tank because of rust most have been driven over ten winters and yes some were steel gas tanks.
the longest driven was a 88 dakota which i bought new and drove every winter for 13 years when i got rid of that truck the entire body was like new! on the floor and under the bed the factory paint was still there under the oily mess.
 

JTK

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@mike78

It's definitely worth the effort, although IMO, FF is better for internal cavities inside doors, rockers, trunk/hatch lids, frame rails, etc.

I have the hardware and product to spray FF and woolwax myself and have done 6-8 vehicle sprays at this point. I like these products, but they will wash off under-vehicle components that catch lots of road spray.

Some of these oil spray type products claim that even when you can't see or feel it on surfaces, beneficial components still hang around (I think Krown claims this).
 
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It depends on two things imo. One is where you live, and two is how long you plan on keeping the vehicle. In the rust belt, and plans to keep the car for ten years or more, I'd do it for sure.
 

mike78

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I do it for myself and friends- it's a lot of work. To me undercoating means rubberized undercoat which is a waste of time. Anti corrosion spray is underbody and inside body panels- I drill a few holes for access to the rockers. For the price of a new vehicle and I tend to hold on to them- I do it and clean the drain holes. Every year is too much- 5 gallons of No drip here is $200.
Definitely not getting the rubberised garbage!
 

mike78

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Then I would do it. $200 sounds a bit steep though, but would be acceptable if your buddy does a tremendous job. That would include spraying all door, trunk, hood cavities, pulling plastic covers and spraying behind them and then finally doing the underside. Ask your buddy what exactly he will spray.

Edit:
Don’t forget rocker panels, they usually have plugs underneath so access to the inside should be easy.
I asked and he said he's planning on doing all those areas you mentioned.
 
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I would use something more permanent. JMO. I live very close to you (RI) and oil based coatings wash off very quickly.

Noxudol would be my first pick, followed by RP342. Be aware they do require a fair amount of prep.
 

mike78

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With fluid film or other light oil based rust proofing product, like Krown or Rust Check, there is no such thing as a touch up. They need to be sprayed all the same every year if you want the full benefit. It’s because they get washed off during winter in most areas exposed to water. Inside cavities don’t need to be sprayed as often though.
I'm pretty sure he means he'll re-spray any areas that need it as part of the "touch-up".
I would use something more permanent. JMO. I live very close to you (RI) and oil based coatings wash off very quickly.

Noxudol would be my first pick, followed by RP342. Be aware they do require a fair amount of prep.
Ok, I'll see what his thoughts are on using one of those products instead. Your logic makes sense to me! I'd rather use something that won't wash off the first time we drive through a big puddle or something.
 
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Noxudol 700 for inside panels like rockers, post, inner body panels and inside suspension parts like control arms and sub frames. Noxudol 300 for the under body and wheel wells. Make sure to get behind any plastic wheel well liners if applicable, rust can really get going under there.

Edit: I just looked at my cans, some of them are 900, both work well.
 
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Back when my dad lived in Billings Montana he told me they kept it washed as well as they could in the summer and that in the winter did it actually staying outside and staying Frozen was better for it than parking it out in the sun or inside of a garage and letting the snow melt off because it seemed then that the oxygen got to and it sped up the rusting process. As a little boy he would let me wash the truck during the summer and then we would get up underneath it and he would touch up the areas that were starting to lose their painted surface or if it was down to bare metal and he would put something on it and maintain it like that.
 
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At this point, I wouldn't do it, even on a 4 year old vehicle. There won't be any way of totally cleaning all surfaces and the undercoating will seal in much of the bad stuff.
I would only do it on a brand new vehicle.
 
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Absolutely!

GM loves to use bare steel for their brake, fuel, and EVAP lines. If you do nothing else, do these. But the rest of the cars deserve it too.
 
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Absolutely!

GM loves to use bare steel for their brake, fuel, and EVAP lines. If you do nothing else, do these. But the rest of the cars deserve it too.
Also after the salt season, it's always good to clean around the rubber bushings where the lines are secured because they have this lovely tendency to trap salt water and eat holes through the lines where it's not visible.
 
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I'm pretty sure he means he'll re-spray any areas that need it as part of the "touch-up".

Ok, I'll see what his thoughts are on using one of those products instead. Your logic makes sense to me! I'd rather use something that won't wash off the first time we drive through a big puddle or something.

If he uses those products i mentioned it will be a good bit more money just FYI.
 
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