I’m looking for technical help or recommendations on:
I bought my NC a couple of months ago, it’s in incredibly good shape despite being 15 years old since it only has 25k miles, one owner and was garage kept and only driven about 1k miles a year during summer, if someone told me it was only a year or two old I’d believe them (pics below).
I took it to a specialist to get an estimate for undersealing, they said it was one of the cleanest NCs they’d seen and joked that me driving it there that day was probably the first time it had ever been out in the rain! (it was pouring that morning).
They quoted me 1k, including the rear bumper mounts.
Now I’m trying to decide if it’s worth doing or not, since I’m not sure how long Ill keep the car, it could be for two years or it could be for 10. However it is my only car, so it will get driven under all weather conditions, including winter, but I don’t need it it for commuting, I only drive it on weekends and every now and then to go to the shops.
I’m thinking of just driving it for a year or two and then if I see myself keeping it long term, invest in getting it undersealed. How much damage could a couple of winters do under those conditions? My plan is to jet was it underneath every other week during winter.
Mine (2009 20k miles) is in the same condition and I am having mine done before putting away for winter.
By Paying a restoration company (Approx 1k) they will be removing wheel arch liners etc to get at all the parts that they know from experience might go rusty. I would not have that detailed knowledge myself.
Once salt is on the roads it rusts even if you regularly wash it underneath.
Further thought. Check status of rubber suspension joint (Droplinks etc) covers and suspension mounts as they deteriorate on a time basis as well as from wear.
Even one winter with salted roads will create corrosion which, once established is virtually impossible to eradicate. I would be concerned that any underseal treatment would just cover but not treat the corrosion. “Rust never sleeps”.
Acf 50 is useless under a car.
As said you could do it yourself with some aerosols from from the likes of Bilt Hamber or Dinitrol, 6 cans of Bilt Hamber UB will cost you £100 so there are some big savings to be had.
Probably beneficial to just do as you say and give it a wash down every now and again and just use it and enjoy it.
It would literally take an hour to coat the underside if it were up on a lift and needed no prep work, any local garage could do that really.
My best guess is after a couple of winters wether you keep it or not you’ll regret not either doing it yourself or getting it done properly.
It really will not take long for the the rust to get a grip of such a clean car. 1k seems to be a going rate for striping back everything to bare metal and applying underseal, make sure you get photographs of striped back underside.
IMHO putting underseal straight over what you have shown us is a recipie for disaster as any corrosion from condensation trapped between layers will eat your car at an accelerated rate. Good luck what ever you choose with such a lovely example.
If you do nothing else - I would treat the inside of the sills with Bilt Hamber S-50 or similar.
Unfortunately the MX-5 has a habit of rotting from inside.
This is easily a DIY job - the 750ml cans came with a 360 injection nozzle.
There are grommets in the front and rear of the sills - and if you pop the sill door trim off there are holes to inject through in the top of the sill.
I’ve just gone through a full “restore” and protection on my 2009 car, really enjoyed the process. Agree with the comments above, minimal inject S50 into the sill and have Lanolin applied underneath.
The thing with ANY underseal or whatever is this.
Preparation ia 100% essential and must be completely dry no ifs or buts.
Likewise, it is also a must that no part is missed during the process.
Is that actually possible…
IF any moisture/water should get in between the metal and coating you just are not going to know until the inevitable rust starts.
That is then worse than not doing it at all.
Mine is in very good condition underneath for a 2013 car and have left well alone.
It gets looked at least twice a year.
Admittedly it is very rarely used in the winter months and also garaged.
Again if it is garaged and put away wet with dodgy underseal that will just speed up the rusting process because generally the air won’t dry it out quickly enough.
Well yours has lasted the last 15 years with nothing on, so perhaps don’t try and fix something that isn’t broken.
Just my opinion and each to their own as they say.
Good luck in your choices.
Unless there is no alternative, it’s never a good idea to put a car in a garage if wet (unless the garage is so huge that it has a good airflow passing through it).
