Undercoating -- good or bad?

Hello! We just purchased a 2018 4Runner TRD. The dealership recommends that we get undercoating. Just wondering if this is a good idea or not. I have heard so many different opinions on this. Thank you!

 

Yes, have it undercoated, especially if you are in the rust belt. Not sure what kind of undercoating they are recommending but i would recommend Krown as its a product I've used and then tons of people swear by fluid film. There are other products out there, just do your research and see what makes sense to you. Another product, PB blasters surface shield has gained some traction lately.

 

Thanks! Are the holes they drill small and difficult to see and something that would not affect resale value of we ever decide to sell it at some point? There are Krowne places nearby -- yes we are in the rust belt.

 

Welcome from the center of the bourbon universe.

 

Welcome. Undercoating is always a good thing, just not from the dealer. Also, with it being a 2018, make sure to take care of existing rust and not just spray over it.

 

Welcome!

 

Yes, I would recommend some sort of undercoating. Whatever you do though, don't go with rubberized groop like Ziebart.

Krown, Woolwax, New Hampshire Oil Undercoat, or Fluid Film are all good type products.

I imagine any holes drilled for a crown would be small, and covered with some sort of a rubber plug. I think the benefits of a non-rusty undercarriage would definitely help resale value more than any little holes would hurt it.

Rust is the Achilles heel of these, anything you can do to prevent it is worthwhile.

 

How well do shops get at harder-to-reach places, such as under the skid plates?

 

Welcome

 

I would personally remove skidplates and the spare before paying somebody to spray krown etc. I wouldnt want to assume they are going to take them off.

And I would not them to, because they would just end up stripping them. It’s really adding a totally unrelated job to the task at hand. So they’re either not going to do it, or they’ll do quick and dirty. Keep in mind; even toyota dealer oil techs commonly strip out the bolts on these because they prioritize speed, or are inexperienced.

Regarding the OPs question on hole drilling/plugs, I’ve seen some pictures of some pretty big plugs! Have them show you before you commit to having them take a hole saw to your ride!

 

I have been debating this one too. I was told you have to super clean very well the entire system before you undercoat specially on older vehicles. Mine is a 2020 and I have done a pretty good amount of offloading so cleaning this thing will be another job in itself. Then, removing skid plates and other stuff takes time. I got a quote from a Houston shop for 1200 a few weeks ago. But they need the truck for 2 to 3 days. I was told that maybe overkilled for a truck that sits in the heat here in TX. So I think I am just going to leave it alone and not mess with it. Other option is DIY and take your time and super prep everything.

 

Welcome from Missouri.

 

I try to spray the underside as best I can then take it to who ever is the best deal to get it sprayed. These products are designed to creep and I figure will seep into the places I need them to, with or without dirt. 1200 is insane and no way would I pay that. Typically I spend around 100 bucks each year, it does make a difference. After traveling down south this past winter, I think the salt/whatever shit they use, is way worse than up my way.

 

Thanks, that sounds like good advice. I suppose I should also get a spray can treat the skid plate myself when I put it back on. Or get a TRD skid plate.

 

If you change the oil yourself, on frequent basis, I don’t think it’s worth coating the skidplate. I generally wash it off at every change (3 to 4 times a year) and it’s holding up well.

 

One of the maintenance procedures I was reading somewhere said you need to remove the skidplate to change the oil, is that right? I expect a coated skidplate would be a pain in that case. I guess that might also be why stripping those threads would actually be a thing, because I wouldn't otherwise expect them to get a lot of on/off cycles.

 

the front one has to come off for the filter. The other one has a removable panel for the oil pan bolt, but I usually take it off anyway to keep an eye on things.

 

Thank you for all of the informative posts!!