After undercoating, which parts shouldn't be sprayed for degradation concerns?

As the title implies I’m expecting some heckling but since this is by far the most important thing I can do to my truck outside of lbjs and others I wanna make sure I’m fully prepared.

when undercoating am I good to basically spray everything I see, or are there certain areas that I should avoid to prevent degradation or lower the capabilities of said part? Like should I spray behind the wheel wells, etc.

for those interested in using surface shield as my product as I heard it might be a little better and last longer then fluid film, also got that wand thing for getting inside the actual frame

 

No idea on long-term protection since I bought a truck that spent a lot of time in Utah but that is now 100% in a dry part of Texas, so my goal was fixing past damage but with zero concern for the future. I removed surface rust (did it with a set of wire brush attachments in a drill) and then coated that. I used a phosphoric acid solution called Ospho which converts rust (wasn't much "rust" left to convert after the wire brush) and then rattle-canned the result with Rustoleum. I did not paint all the front suspension components super hard core because I plan to replace all that. For long-term protection (I see you're in New Jersey), I'll let one of our northern brethren chime in. I did watch a lot of videos at one point, and one guy (not the Farm Science or whatever dude) who did a long-term side-by-side test of several products, swears by the somewhat newer PBlaster coating since it doesn't evaporate (like WD40) or get all gunky (like woolwax), which he also applies with the spray tip wand things to get all up in them guts of the frame.

Edit: I see now that PBlaster product is called Surface Shield which you mentioned, so yeah you seem to be watching the same videos as I did, haha.

 

Wheel wells are plastic covered, so no. Inside the bottom of the door would be a good place once you insure you don't have anything rusting in there already that needs to be cleaned and prepped first.

 

Has anyone used Woolwax Hard-On Permanent? The prospect of not having to recoat every year is inviting.

 

Most of the wax/oil base stuff that has to be reapplied annually, works fairly well.
I would avoid anything that is like a paint, tar or rubber type coating. It will trap moisture.

 

To add onto that, I’m trying to prevent the metal parts in my engine bay from rusting like you see in engine bay pics of most trucks in the north east. You think I should put some surface shield on those components too to prevent that or should I look for a different product for that

 

@FirstGenVol how is your Fluid Film holding up?

 

no as in I don’t need to worry about spraying?

or no as in don’t spray there lol

 

Dont spray on there.

 

It holds up pretty well but does have to be reapplied. I actually don't like how well it works in places. After driving in Arizona all that dust stuck to the frame and other areas I sprayed.

 

Thats why im hesistant to use some of this on my engine bay parts, heard that these films collect dust which may help its effects for the frame, but would leave my engine bay absolutely cruddy. I might look into some other rust prevention products in the PB blaster line for this maybe.

 

I thought that was actually good for the "rust protection" aspect as it adds a layer of protection.

I've read and seen posts on guys spraying, then driving down gravel/dirt roads to add it right after spraying.

 

Buy a skid plate to put that fear to rest.

 

lol I’m more so trying to prevent it from the salty roads come winter rather than it getting filthy. I don’t want the eyesore of seeing rusty hooks, crooks, and bolts.

still gonna use it for undercoating tho

 

The skid plate will keep most of the salt/brine out of the engine bay and protect the front frame and crossmembers. You just have to remember to spray fluid film on the skid plate to protect it as well.

 

Another dumb question but figured it’s not worth a seperate thread, but is there a concern about the difference in these air filters?

I ordered the new one from a local Toyota but the filter in the original seems fatter with less grooves. I can’t help but shake the feeling this dealership took the lazy way out and just gave me something that would “fit”. Another idea is that there’s been different iterations or versions over the years and this is the one they got in stock. I can’t think of a reason why the slightly different filter would be detrimental tho if anything more benefitual in filtering maybe with more grooves.

 

Nvm i answered my own question, I double checked with mcgeorges and it looks to be the same and part number so I should be good

 

Yeah I'm not sure why you would spray Fluid Film in your engine bay. I've only used it on my battery terminals. For your frame it's good. PB Blaster Surface Shield is good too. Some say it's better.

 

Basically trying to avoid this from happening.

 

That’s inevitable. You’ll always get a small amount of rust in the engine bay. The trick is to make sure most bolts are coated with anti-seize or penetrant oil to insure they wont cause issues further down the line.

Of you’re anal about keeping it pristine, you could probably use wd40 to coat the parts subject to rust so long as it doesn't burn off and give some horrible toxic smell.

 

Keep your skid plate on at all times to help cut down on it.

 

Guess the solution isnt as simple as I hoped it to be. Was hoping there was a alternatve wb40 ish product ppl recommended that didn't have those kinda issues. All good, ill just stick with undercoating the frame and like yall said, use the skid plate for what it was designed to do.

 

Its hard enough keeping rust off the frame that I think most people don’t deal with detailing the engine bay and keeping it immaculate. If you find something that works, let is know. Most people in that category around here generally don’t take their truck out in bad weather and have an alternate beater to drive.

 

You're 100% right, but don't get me wrong, I'm not trying to showcase the thing and fine if it does rust over time, just figured id ask if that was something I could do while i'm over here winterizing the truck anyways, thats all

 

Depending on which undercoating you decide to use, read the directions on each product as some don't recommend it to be sprayed on any rubber components.

 

Tons of good answers in here. I think the dirt/dust after using was a PHM thing. It's inevitable no matter how ya look at it.
I vote akif plate like.others have said, make sure all of you're splash guards etc. Are where they are supposed to be and in the winter with all the shit they put on roads don't let it sit and collect. Wash often just to knock it down. I believe you can use a baking soda mixture spray to help break up the salt if ya want. I wouldn't go crazy just lower areas and stuff that's not a mechanic moving parts like brakes etc.
I will say my faves up front skid/splash guard made a ton of difference in the winter as I did t have one when I bought due to lift I assume.

 

I also heard some guys suggest not washing all winter to preserve the undercoating while others seem to wash the salt off regularly so the salt doesn’t sit and in theory the film is water resistant. Not sure which train of thought to follow come the upcoming months

 

GM dips their truck frames in a waxy tar coating and they don’t seem to have nearly the corrosion issues Toyota has. Just a thought

 

You can grease rub your frame then spot spray with FF or blasters surface shield...It's a lil messy but it doesn't wear off, if it does it doesn't do it very easily.

 

I use WD40 on the frame and in the engine bay. Works really well -- and I'm in Maine (harsh winters with very salty roads).