let's talk undercarriages

[House of Wax]

` This is more of a question for those that deal with real winter weather.` Do you guys do anything to the underside of your vehicles to help protect against rust?` I`ve got an 07 Ram that I plan on driving until the wheels fall off, and while the the paint is in great condition I worry about rusting issues from the back side of the panels (especially in the rear wheel well area).` I`m wondering if a periodic application of a product like carpro`s Hydro2 would do any good or if it`d just be a waste of time.`


`


Thoughts?

[Grimm]

You might be better off researching any rust prone areas you can proactively fix if possible.` I just traded in a 2003 Bonneville, and the underside looked great after 11 Michigan winters.` The issue I had, was it was rusting below the gas fill area.` The genius engineers not only put a hole in the fill area that allowed water/dirt from the tire to get in there, but they used some sort of moisture absorbing adhesive to attach the fill neck to the quarter panel.` The combination results in rust, but I found out when it was too late.`

[House of Wax]

I`m kind of on the same thoughts as you. I got to thinking about this when I rotated my tires last weekend. I poked my head around and didn`t see any issues, but it got me thinking about ways to keep it that way

[StreetShotz]

I have used products in the past to help stop/prevent rust. Things like Por15 work well for things like inner fender areas. Its both a rust inhibitor so any existing rust there will be altered to stop it from rusting and it provides a durable coating to stop any further rusting.`

A good coating like that, regular washes and it will last a very long time. With a truck its easier as you can get under there and wash easier than you can with a car. Often times in the spring I will put the cars up on jack stands and crawl under to pressure wash the whole underside and inspect for any new issues. If you note things down in a log you can refer back to it the next year and see if things have become worse.`

[House of Wax]

I`ll check that out, thanks. Good idea on the log too

[Accumulator]

Funny you should bring this up today, I`ll soon be dealing with some chips/surface rust on the Crown Vic`s frame.` And some day I`ll do the entirely-surface-rusted frame of the Tahoe (yeah...some day :huh:`).` My other vehicles are OK in this regard, "OK" as in everything spotless and at least spray-waxed if not properly LSPed.


`


There`s a thread around here somewhere in which we discussed this Rust/Undercarriage stuff`in great detail, and Ron Ketcham made some very good points.` Well worth the dreaded search.


`


On most vehicles I just keep things very (and I mean *VERY* )`clean.` I`ve generally been able to clean off the salt/etc. without trouble, but some locales use stuff that`s a *REAL* PIA to get off.` I mean every square centimeter, every wash.` I simply do this to all my vehicles usually even in the summer.` Yeah, jacks (I keep three in the wash bay area) and stands... every. single. wash.` Note that this has worked fine on the already-rusty Tahoe; it`s structurally OK and there`s no sign that any of its rust is anywhere near perforating.


`


If you see a chip, or any rust starting, and they concern you ;)`then deal with them before they get worse.


`


Spraying rust inhibitors can be tricky as it`s *SO* easy to get "pockets" that will retain corrosive stuff and lead to the rust you`re trying to avoid.` IME many/most aerosol undercoatings are prone to this and it`s far better to use an actual undercoating gun at high airline pressure.` With good stuff like the ValuGard product.` The big trick is to do the inaccessible areas properly, and that`s just not that easy to DIY (I got a lot of coaching at an young age from a guy who did it professionally, it`s just not as simple/easy as one might think to do it right).


`


For very tight spots where you need "creep" to get in there (e.g., riveted areas), there are`a few products`that work well IME, far better than typical OTC stuff.` Research ACF-50 and Wurth Rost-Off Plus and Amsoil Heavy Duty Metal Protection`(I use all three with great results).


`


For less tricky applications I`ve done`well with Eastwood`s Black Heavy Duty Anti-Rust.` Nice stuff that dries black and doesn`t stay tacky.` For areas you can access, and for those areas that you will see, it`s great stuff and really easy to touch up.` AFAIK it`s the only "rustproofing" stuff in the "like Ziebart" category that dries black.


`


Paint-Over-Rust products: I started with POR15 and it`s...eh.... mediocre IMO.` There are other similar products on the market these days that have worked much better for me, including Rust Bullet, Rust Seal by KBS Coatings, and Eastwood`s Rust Encapsulator (which doesn`t require a topcoat for UV protection like most such products).` Note that these products are not all that easy to touch up (it can be done but requries sanding/etc.).


`


Ya know...I honestly think that most people who area concerned with actual rust-out should just get the vehicle rustproofed by a pro who uses ValuGard stuff.` It`ll be unsightly, not a "concours-look" undercarriage, but it won`t rust away.` That corrosive-laden water just creeps into everywhere and for most people, washing it away before it does damage simply isn`t gonna happen any more than a proper DIY rustproofing is gonna happen.` Where a body mounts to the frame is a perfect example- IMO most people will spray stuff, confident that they did it right, and it`ll trap sal````er and years later it`ll be worse than had they just washed it every week.

[Lonnie]

Here`s another issue concerning washing off winter salt in an attempt to prevent rust: tunnel car wash places that use recycled water.


While the filters/water conditioners will remove debris and SOME of the chemicals within the filtration/conditioning system, it will not remove ALL the sodium chloride`(chemical name for salt) from the water if its not properly serviced.


While washing your underside is a good idea at a tunnel wash when it`s cold because it`s impossible at your home, depending how often the filtration/water conditioning`system at that wash services those systems, you may be just rinsing off the salt with a brine solution anyway. You need to ask the tunnel wash owner/manager if they do, indeed, use recycled water and if they do, how often they change the filters`and/or service the water treatment systems.


`


Seems to me that someone wrote within this forum that GM cars of the late 90`s that had their paint start blistering and peeling was because of the harsh alkaline chemicals used in soaps at tunnel washes at that time. The more often you used those washes, the worse it became. I`ve seen a lot of peeling on those`GM cars from that era, especially Chevy`s and Pontiacs. I always thought it was because of the water-based clear-coats that they used that did not hold up well over time and lack of car surface care by the owner, like prudent waxing/sealing.

[rdorman]

I used to use Sonus Trim and Motor kote on the bottom of my Cobra after a good wash. Held up half decent.

[Accumulator]

I never got around to trying my Sonus T&M K before it went bad.


`


One of these days I should get some of Garry Dean`s Juice Boost, turn my IUDJ into a LSP.` I figure that since I`d be under there cleaning anyhow, that`d work OK for the stuff I don`t LSP/coat.` Might work so well that I won`t do any more of the latter!

[Ron Ketcham]

Valugard, produced by Automotive International, also produces the rust preventive product and the undercoating product, under private label for Ford and Chrysler. Sold as MotorCraft or MoPar (Master Shield) for them. These products are the only ones that they either use or recommend for repairs. In the case of Chrysler, the Master Shield line is their after market warranty products, warrantied by Chrysler.


ValuGard, MotorCraft and MoPar are all the same products, just different branded labels.


If you are serious about understanding the "real" world of what they do, how they protect, how they are applied, etc, suggest you visit the Valugard.net website.


On the site are several Technical Service Bulletins from various vehicle manufacturers regarding the required used of the products,`


There is also a couple of "training video`s" showing the correct application methods.


Today, it`s not just "salt" used on roads that you should be concerned about, but the growing use of "mag choride" and it`s ability to continue to create corrosion (rust), even in the warm weather, once it comes in contact with your vehicle.