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Undercoating?

8499 Views 15 Replies 9 Participants Last post by  pshadoa
Is that a thing anymore? I hold on to my cars for a long time hence the 2007 Pilot. I am wondering if I should consider that at some point.
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Don't use rubberized undercoating. If anything, use a solvent-free lubricant like Fluid Film.



Modern vehicles do not have to be undercoated...It is a rip off by the dealers to get extra money.
Modern vehicles do not have to be undercoated...It is a rip off by the dealers to get extra money.
Is that because they are made better or just don’t last that long anymore
Modern cars are made of galvanized steel with layer of zinc......Very unlikely to rust....Lots of info on this just google it.....Any dealer accessories have to be looked at with a jaundiced eye....either not really needed or are marked up to the stratosphere. I worked as a new car (Honda) salesman once..very short tenure...I still remember the sales manager calling us all into the room and drilling into us that these add ons are a money machine for the dealership and therefore for the commission earned by the salesmen.
One other thing..If you really want a particular dealer add on by it directly from the service dept...way cheaper.
I believe that under carriage wash often is better then any under coating. I had a 1999 Taurus for about 20 years without undercoating pertection, the car was worn out when I sold it but, the undercarriage was in good shape.
Be careful with non-factory undercoatings. Some are known to actually trap in moisture and cause more rust than without the coating itself.
Sorry to bring up an old thread but I'm anal about my vehicles and tend to keep them a long time. I've used rubberized undercoating on quite a few cars and never had the issue shown in post #2. Maybe I've just been lucky.
anyway, I noticed that there is a huge amount of bare metal on the underside of the Passport. Apparently it's not an issue so I will probably leave it as is. But there is a lot of bare metal exposed in the front wheel wells and I would think it would be susceptible to chips from gravel and other road debris, especially if used off road at all. Has anyone here applied anything to this area?
As a side note, I had an Audi S4 many years ago. At that time they had a 12 year unlimited mile corrosion warranty. They used galvanized steel for all body panels and even used hot dipped galvanizing on the areas that weren't visible like the undercarriage and lower structure. In addition to that the entire undercarriage was coated in a thick tough urethane. Maybe they don't go to those extremes anymore as it was unnecessary.
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I have been wondering if a "rubberized" undercoating in the plastic wheel wells would reduce tire noise. Thoughts ???
I live in the San Diego area which has a very mild climate. No snow, very little rain.
I used a liquid truck bed liner. Bed liner coating I removed my plastic wheel liners (on my MDX) and painted 2 coats on their hidden side.
If you're interested, here's a youtube review video, for paint-on bed liners...Trust this guy's videos

(MDX)...My tires had 7/32nds left and were getting noisy. The bed liner did not help and I replaced the Scorpion Verde tires with new Goodyear Weather Ready tires. New tires are significantly quieter than tires that are 1/2 worn down.
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I used a liquid truck bed liner. Bed liner coating I removed my wheel liners (on my MDX) and painted 2 coats on their hidden side.
Here's youtube video...Trust this guy's videos
Thank you for the idea! Did you find the coating reduced tire noise? I switched to 18" Ridgeline wheels and what Tire Rack and Discount stores (several of each) told me were the quietest all-season tires available. But I have very sensitive hearing, and while others that ride in the PP say the tires are " whisper" quiet, I find the tire noise to be irritating. This after trying two different brands of the recommended "quietest " tires.
I used a Db meter $15 before and after the coating that I put on the plastic wheel liners. I drove on the same stretch of new asphalt and saw only 2/10 Db improvement. So yes it did help, but it wasn't worth the labor.
My new 2019 Passport Touring is at 64 Db over that stretch of road.
My old 2007 MDX was at 69 Db with new Weather Ready tires and at 72 Db with Pirelli Scorpion Verde Plus tires that had 7/32nds life remaining (after the bed liner coating).
When I replaced my 20" wheels with 18"s I first tried the Continental Contact LX25s. I thought they were noisy even though having a 8.8 rating for noise. So I replaced them with the Pirelli Scorpion Verde Plus II tires that have a 9.3 noise rating. I too used a Db meter and both tires were about the same. Supposedly my old Touring wheels had a foam noise reducing strip around the inside of the wheel. I never saw them w/o tires mounted so I do not know for sure. If so, maybe that is why I feel these new tires are noisier. I previously replaced the door speakers with better ones and put sound deadening material in the doors. So just drive with the audio turned up ! :)
I read Honda's research info on sound deadening road noise the 20" Passport rims have a sound deadening strip, but didn't know how well they worked until your comment.
Road noise goes down as the amount of rubber, between the rim and the road increases.
You mention the Db levels were the same, between your OEM 20s (with sound deadening strip) and that of new 18s (without the sound deadening feature). Effectively, the sound deadening strip equates to having more rubber between the rim and the road.
Now I need to find out if any Honda/Acura 18" rims have the sound deadening strip and can be used on my Passport. I haven't checked the rims sizes on newer Hondas/Acura, which might be designed to be more sound conscience.
More on Honda's R&D road noise
I read Honda's research info on sound deadening road noise the 20" Passport rims have a sound deadening strip, but didn't know how well they worked until your comment.
Road noise goes down as the amount of rubber, between the rim and the road increases.
You mention the Db levels were the same, between your OEM 20s (with sound deadening strip) and that of new 18s (without the sound deadening feature). Effectively, the sound deadening strip equates to having more rubber between the rim and the road.
Now I need to find out if any Honda/Acura 18" rims have the sound deadening strip and can be used on my Passport. I haven't checked the rims sizes on newer Hondas/Acura, which might be designed to be more sound conscience.
More on Honda's R&D road noise
Thank you for posting the info re the sound deadening strips. It was very interesting!
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