Hi my Mk3 is coming up to its MOT and was looking at undersealing it to help protect it form rust as it starts to get a little older. Any recommendations for good underseal brands to use?
Thank you for the help
I have got inside my hollow sections with Bilt Hamber Dynax S-50 Anti-Corrosion Wax. I don’t know how good it really is yet, but application seems to work well. Certainly the description seems good.
This is a huge topic, have a good look on the forums to get a sense of the pros and cons of the various recommendations, including self application v. paying to get it done. I used Waxoyl professionally applied, which is quite an old-school method but many people are happy with it. Others swear by newer Dinitrol. How long is a piece of string…
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Dinitrol, Bilt Hamber products are good. Other products too no doubt.
I chose to get themx5restorer to do our ND, on the basis that they know where to put the gloop. That was when it was 6 months old and pristine. At 6 years, there is no visible sign of rust and I think it was well worth it.
Yours will likely need prep, e.g.cleaning, removal of loose rust, rust conversion before application.
Prevention is better (and cheaper) than cure.
i had my 2013 NC done my the mx5 specialist at thrussington near leister.
they use some modern stuff that sets hard as metal.
its been on their about 18 months at this point and is still solid
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This is critical on any car that isn’t brand new/totally clean, putting rust prevention product on already crusty bits will not stop the rust and you’ll likely find the product dropping off quite soon.
That is why I found the Bilt Hamber products such a good option for inside the hollow sections as it incorporates a rust converter. I was able to spray it far up inside the curved sections of the sub frames, as well as the notorious sill boxes
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I’m thinking about this for my 2014 MK3 too, can anyone recommend a good workshop that will do it in the Hertfordshire area? Always like to go on recommendations!
JohnM is spot on, unless it’s been stored in a vacuum any NC probably already has enough rust to make it a “derust and rustproof” not a “straightforward underseal”. It’s not a small job to do right, and it’s often worse to do it badly than to not do it at all. Putting most underseal products over a rusty car is like sealing wet stuff in a box.
There is another option, which is to properly half-■■■it. No, seriously. As soon as you start putting permanent products like underseal on, that’s potentially a problem but there are products you can’t go wrong with. Something like XCP Rust Blocker in the cavities, frinstance. Wire brushing off any rust scale and then applying a product like Lanoguard literally everywhere but the discs, is not as good as a full on job but you can do it in an afternoon or two (depending on how much rust and how intense you get) and it’ll give a good protection topup.
Basically, mine is getting right back to metal where it needs it, subframes out, a proper job. But if I had, say, a down-at-heel 1.8 and no expectation of keeping it more than a couple of years, I wouldn’t do that, I’d half-■■■it just to kick problems down the road a few years.
Thanks for the info, I was looking at doing the front and rear subframe and the rest of the underbody. Do you know how much of the product would be enough to do the job?
It took two of the large spray cans.
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