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Undercoating and rustproofing Tesla Model 3

dfwatt

Active Member
Sep 24, 2018
3,122
5,129
FL
If you are like me and living in New England where the roads are salted 4 months out of the year if not more, you're a bit paranoid about rust. An ostensibly well rust proofed from the factory Lexus showed pretty extensive rust after 10 years in New England, adding to my paranoia in the context of Tesla's well documented quality control issues. My paranoia about this was not helped when I saw that there was already rust on the stainless steel hub of the front wheel, after just a month and even before any winter time salt had any opportunity to wreak havoc.

So I decided to investigate undercoating and rustproofing - as much as one can do that - of the undercarriage and suspension parts, starting at the rear. This for sure is not as glamorous as getting new wheels, tires, or coilovers, but you'll be glad you did it 5, 8, and 15 years down the road if you keep the car that long.

Here's what I did and what you will need to duplicate it - and it turned out to be surprisingly easy:

1) 8 cans of Rust-Oleum rubberized undercoating, readily available at Walmart, AutoZone, and on Amazon. Any rubberized undercoating will work pretty much just as well as Rust-Oleum but it's more widely available.
2) 2 cans of CRC, also available on Amazon.
3) Jack the car up safely preferably using a jack pad, and take off the rear tire.
4) remove the liners inside the rear wheel wells which are held on with a connection of screw posts and snap in clips.
5) you will now have access to sheet metal what you will see presumably coated with some kind of electrically deposited primer. And you will also have access to the rear suspension without as much obstruction. You can see in this first picture how sheet metal looks prior to rubberized undercoating and afterwards as well.
20190307_184141.jpg

20190308_172346.jpg

6) take the CRC and spread on all exposed suspension bolts and nuts and any other ferric metal, but avoid wiring
7) take the fibrous and frankly somewhat flimsy interior wheel well liners out carefully, making sure you don't tear them. You may have to cut them at the top seam as it appears they were glued together from two separate sections. Don't worry about cutting them because it's easy to join the back together at the top what you will do on reinstallation.
8) take one entire can of rubberized undercoating and liberally coat the inside of the fibrous wheel-well liners. This will make them both more durable and potentially somewhat more absorbing of road noise which is an issue in any case with this car despite it having a very quiet drivetrain.
20190308_172401.jpg

9) wait about an hour at least for these to dry completely and carefully reinstall using clips and screw posts. Probably a good idea to pick up some extra clips which are 8 mm in size and actually are identical to what Honda uses - you can get these at any AutoZone for a few bucks and you'll use them up anyway as they have a tendency to pop off.
10) optionally, you can clean out the underneath tray which is full of sand and Grit. It's a bit worrisome how much junk gets in there. There are already threads on this issue. This is on a car with only a couple of thousand miles so you can imagine how much sand and grit gets in there after a year.
20190307_184127.jpg
 

dfwatt

Active Member
Sep 24, 2018
3,122
5,129
FL
This whole process takes about an hour and a half or at most 2 hours per wheel well. But it's well worth it because you have rust proofed exposed suspension metal that is prone to rust, strengthened the wheel well Shields, and undercoated and perhaps modestly soundproofed the underlying sheet metal. It should offer a significant increment of protection for folks living in Northern climates. Feel free to post if you have questions or comments.
 

Paul73

Member
Mar 10, 2018
18
5
uk
I've just ordered Lanoguard Marine and Chassis trigger spray - Lanolin based, similar to a thick fluid film?

Maybe reapply before each winter (UK salted roads), and rinse off salt underneath every week or more with water.

It will be interesting to see how easy it will be to get access, and where to apply it? (none on brake discs or pads as it's a lubricant)

https://electrek.co/2017/08/22/tesla-model-3-body-alloy-mix/

p.s. careful with rubberised coatings on metals, they can trap moisture and hide rust for 10 years until it's too late (youtube shows videos of this - certainly with existing rust before coating)

Lanolin can be removed with a citrus cleaner if needed
 

dfwatt

Active Member
Sep 24, 2018
3,122
5,129
FL
I've just ordered Lanoguard Marine and Chassis trigger spray - Lanolin based, similar to a thick fluid film?

Maybe reapply before each winter (UK salted roads), and rinse off salt underneath every week or more with water.

It will be interesting to see how easy it will be to get access, and where to apply it? (none on brake discs or pads as it's a lubricant)

Tesla Model 3: here’s the alloy mix of the Model 3 body

p.s. careful with rubberised coatings on metals, they can trap moisture and hide rust for 10 years until it's too late (youtube shows videos of this - certainly with existing rust before coating)

Lanolin can be removed with a citrus cleaner if needed

Well obviously it would be a profoundly foolish thing to do to spray this on a car that had wet sheet metal. As for their effects on existing rust, which would you rather have? Rust exposed to the air and accelerating or rust covered with a rubberized paint? Obviously it will not completely stop the rusting process - almost nothing does, except for some plasticized compounds such as the one Dupont released 25-30 years ago. On a brand new car that is dry, the chances of rubberized undercoating contributing to as opposed to prohibiting and preventing corrosion seem rather small if not zero.
 

dfwatt

Active Member
Sep 24, 2018
3,122
5,129
FL
I've just ordered Lanoguard Marine and Chassis trigger spray - Lanolin based, similar to a thick fluid film?

Maybe reapply before each winter (UK salted roads), and rinse off salt underneath every week or more with water.

It will be interesting to see how easy it will be to get access, and where to apply it? (none on brake discs or pads as it's a lubricant)

https://electrek.co/2017/08/22/tesla-model-3-body-alloy-mix/

p.s. careful with rubberised coatings on metals, they can trap moisture and hide rust for 10 years until it's too late (youtube shows videos of this - certainly with existing rust before coating)

Lanolin can be removed with a citrus cleaner if needed

I did some investigating. Lanoguard and other lanolin based products should not be conflated with undercoating and metal coating products. This is essentially a lubricant and something that also helps prevents the electrolysis that accelerates rust. You cannot use it on sheet metal as a rust protectant, due to the simple fact that it has no abrasion resistance. In other words sand and salt will remove this from the surface and then you are no longer protected. It is appropriate to put on moving Parts on the other hand but it is not something that you can use as undercoating. CRC is probably a better protectant for suspension components including the rear suspension bushings and associated lock nuts. Lanoguard is not in that sense strictly speaking an alternative to undercoating sprays but rather a different product with a different purpose.
 

wycolo

Active Member
May 16, 2012
3,095
429
WA & WY
For the steel Teslas it might be best to wait until yours shows signs of rust and then hit those areas with a warm mixture of: (1/3 used 90-weight gear oil & 2/3 used hydraulic fluid). Both fluids are obtainable at scrap yards and repair shops. Use a power sprayer; twice a winter season should be enough for even the severely salted highways.
--
 
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dfwatt

Active Member
Sep 24, 2018
3,122
5,129
FL
For the steel Teslas it might be best to wait until yours shows signs of rust and then hit those areas with a warm mixture of: (1/3 used 90-weight gear oil & 2/3 used hydraulic fluid). Both fluids are obtainable at scrap yards and repair shops. Use a power sprayer; twice a winter season should be enough for even the worst salt areas.
--
Waiting until you see rust on sheet metal is too late. I'm not sure where you got this bizarre idea that you should wait until your car rusts and then do something about it.

Perhaps you should wait until cancer metastasizes and try treating it at that point instead of preventing it. You will probably find it works just about as well as your solution
 

wycolo

Active Member
May 16, 2012
3,095
429
WA & WY
The 90 weight grease seeps and penetrates, effectively stopping rust. You see this on old chassies around steering boxes that have been slowly leaking for many decades; the frame remains in perfect condition wherever the extent of the 90w. Waiting is to allow the factory paint etc to try to do its job protecting from the salt. Who knows how long these will protect, but at least give them a chance.
--
 

dfwatt

Active Member
Sep 24, 2018
3,122
5,129
FL
The 90 weight grease seeps and penetrates, effectively stopping rust. You see this on old chassies around steering boxes that have been slowly leaking for many decades; the frame remains in perfect condition wherever the extent of the 90w. Waiting is to allow the factory paint etc to try to do its job protecting from the salt. Who knows how long these will protect, but at least give them a chance.
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Perhaps this is viable as a solution to treat rust once it has gained a foothold. But wouldn't it be better to prevent rust in the first place and then if that fails come up with some kind of non-mobile lubricant?

The other significant differences the Tesla really doesn't have an under-chassis in the traditional sense except around the suspension boxes. It's got a big plastic floor covering the battery pack and that is essentially not exposed to moisture or potentially any form of corrosion one hopes. That's pretty different from a traditional internal combustion engine car or the entire length of the chassis outside the suspension boxes is a Haven for rust. And there's one final wrinkle and that is you really don't want to get even 90 weight oil on suspension bushings as oil attacks the rubber. WD-40 on the other hand protects the rubber.
 

dfwatt

Active Member
Sep 24, 2018
3,122
5,129
FL
Curious if the rubberized under coating in the wheel wells will reduce road noise?

For sure magnets that was one of my questions. I toyed with the idea of putting Dynamatting on the underneath chassis metal because there's no room to do it in the back wheel wells because you got the battery and Associated Electronics blocking access. I elected not to because I'm not confident about the longevity of dynamat on an outside facing piece of sheet metal ( even if it was shielded from Road spray by the liners) but I do think the rubberized spray penetrates the fibrous liners pretty nicely.

I also I'm concerned about those fibrous liners having great longevity as they were already starting to 'pill up' analogous to what a cloth sweater might do under abrasive impact in terms of rocks and sand partially disassembling the matted fibrous structure. I'm not sure what the binding agent is binding the fibers into a mat, but I don't think it'll stand up to an enormous pounding by rocks and other abrasive material. You can see in this picture below how the 'pilled' areas are already starting to become visible. Hopefully the rubberized undercoating penetrates and protects these wheel liners at least somewhat. As for whether or not it quiets things down, I don't know and I don't I think it will make a huge difference but it certainly can't hurt. I did this mostly to ensure that the car remains rust free as much as possible
1552245096318585377614239986762.jpg
 

duanra

Active Member
Dec 14, 2018
1,261
726
Montreal
Bought my car in December. Got in touch with a specialist of rust treatment for EV who is so swamped with work that my appointment for rustproofing is in November 2019 ! I live in Quebec.
When I showed some concern related to the time I'll have to wait, he said that the M3 is very well rust protected and 1 year without extra protection is not going to make any difference.
 

dfwatt

Active Member
Sep 24, 2018
3,122
5,129
FL
Bought my car in December. Got in touch with a specialist of rust treatment for EV who is so swamped with work that my appointment for rustproofing is in November 2019 ! I live in Quebec.
When I showed some concern related to the time I'll have to wait, he said that the M3 is very well rust protected and 1 year without extra protection is not going to make any difference.

I would agree from my disassembly that it is well protected from rust but not exceptionally well protected. The other problem is in addition to road salt in New England we have marine salt in Florida especially around Miami and other places prone to flooding in the context of sea level rise.

So bottom line - pretty good protection against rust may not be good enough where we live. Hence my efforts in this regard. Given how easy it is to do even if it is a bit grungy working with this material, seems like doing this kind of undercoating yourself has a very good benefit-cost ratio.
 

duanra

Active Member
Dec 14, 2018
1,261
726
Montreal
I wish i could do it myself, however I am staying away from tools to avoid getting my self in trouble :)

The rust proofing i am going to buy cost around 400 cad. However the guy has a stellar reputation. I totally agree, I wouldn't count on the initial protection Tesla put on car unless I was planning to trade in the car in a few years. I have seen the difference after a 8 years or so between a car rust proofed and a car left without protection...
 

Magnets!

Member
Jan 9, 2019
661
284
California
Did the spray add much weight to the liners? Any concern that will cause an issue? Perhaps the aftermarket will offer a higher quality, more sound absorbing liner at some point.

Let us know as you drive it some more about your thoughts on road noise reduction.
 

ricohman

Member
Dec 31, 2018
470
319
Saskatchewan
Rubber undercoating can trap water inside next to the sheet metal. It always develops small holes.
I spent years as a body man learning this. Scraping it off to get at the rust beneath. GM and Toyota have TSB's denying warranty for rusted frames if they had undercoat applied.
By spraying the liners you are ensuring that they may never dry completely, or at least take a very long time to dry. I don't know if the carriers in that undercoating are good for the adhesive that binds the material they are made of together.
The oil based sprays are the best. But should be touched up annually.
 
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dfwatt

Active Member
Sep 24, 2018
3,122
5,129
FL
Did the spray add much weight to the liners? Any concern that will cause an issue? Perhaps the aftermarket will offer a higher quality, more sound absorbing liner at some point.

Let us know as you drive it some more about your thoughts on road noise reduction.

The spray probably added about a quarter to half a pound at most each liner and since the liners are so heavily and redundantly clipped in place I'm not too worried about the extra weight. For sure I will post if I feel there's a significant reduction in road noise.
 
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