I’ve recently bought a 2003 MX5 on the autotrader with my retirement payment due to always want to own one. The car and bodywork are in reasonable condition for the vehicles age however how often should I protect with underseal? Just been reading this feature here https://www.tiltrak.com/car-rust-proofing/ Is it possible to apply the treatments yourself or best to seek to an experienced professional?
“Underseal” covers a multitude of sins. I’m not keen on the old fashioned bituminous stuff that went hard and let moisture in behind it, sometimes incubating rust rather than preventing it. Probably not what you have in mind. Thankfully there are better products around now.
Also it’s more than just chucking it on. Strip the necessary parts to get access (e.g. arch liners).Assess any rust that needs fixing and do the repairs, remove any earlier underseal that has rust underneath it, wire brush surface rust and treat with rust converter, apply treatments.
If it were me I’d consider taking it somewhere like The MX5 Restorer (I did - I’m not an expert) but if you are limber enough, have somewhere to do it and don’t mind the work and the muck, you can of course do it yourself.
Spot on John.
Unless the OP’s car has been a garage queen, there will almost certainly be areas of corrosion requiring attention.
I’ts just a question of degree…and where.
All sortable though in the right premises.
The link in your post shows one of the most widely used modern brands, Dinitrol. You can buy the various products from a supplier if you want to go down the DIY route. On the other hand there are plenty of places around that do underbody treatments, but be warned there are good and bad. If their service is quick and cheap it won’t be good. On a car that has been around for a few years it will need proper preparation prior to application, so you’re looking at a couple of days or so, and prices from around £400.00 up.
PS: You don’t say where you are. May I suggest that you go to “My Profile”, click on “Edit Profile” and add that in the “Location” line. It will save people saying “where are you” if you ask for a recommended garage/dealer etc.
You rustproof the car once but at the age of your car there will be existing rust needing repaired and the sill cavities need inspected with a boroscope as the sills may well need replaced.
After that once a year an inspection is required and any surfaces that have lostthere coating needs repaired.
It will only take say half an hour every year once the car is sorted.
You can do it yorself but to be honest unless you have access to a car lift, bite the bullet and. pay someone who has a car lift.
23 year old car here. After 23 years, I got it undersealed professionally. The factory finish did fine up to that point. Along the way, the sills and rear arches rotted out, but undersealing wouldn’t have stopped that, neither, I suspect, would most sill treatment (my other MX5, recently sold, had a dinitrol treatment when imported. Sill internals were said to be in a worse state than other car which had never been touched). Personally, I think its mostly a placebo effect.
I suspect a biannual chassis steam clean would also be effective.
Rust proofing a car always needs to be done as soon as possible - preferably within the first couple of years of the car’s life. After that, the chemical reaction that causes rust would already have begun.
A sixteen year old car (like the OP’s 2003 NB), if not previously treated earlier on in its life, will, in all probability, have corrosion well advanced by this time - and NBs are notorious for their front chassis rails rusting, due to their particular design.
The thing to do here, having just purchased the car, is to check all the usual weak points, to determine what, if anything, has already been done, and take it from there. All anyone can do is to attempt to delay the inevitable - the corrosion process cannot be reversed.