I’ve never actually used Waxoyl, or Dintrol for that matter, on any car I have owned. Having been a car mechanic in the 1970s, and experienced most new cars that I had worked on being fully undersealed from the factory back those days, then being out of the trade for some decades, and admittedly somewhat out of touch, I assumed that in the 21st century, all new cars would have been so protected.
I have had the luxury of having the use of brand-new company cars for many years now, so didn’t really care if what I was driving was protected or not - I wasn’t going to keep them !
However, having recently bought a 2008 MX-5 2.0L Sport coupe, and joined the Owners Club last November, I was surprised to learn that Mazdas are not in fact protected very well in this respect, so as this car is intended to be a ‘keeper’, I was asking for advice on the best treatment for it.
Other posts I have read on this forum, seem to recommend Waxoyl or Dinitrol for cavity protection as a must, although the jury seems to be out on whether or not it is also a good idea to have the thick black gungy stuff sprayed on as well.
The more this thread goes on, the more opinions that are expressed, the more confused I am becoming as to what is the best way to protect my 5 !
I will follow this thread with interest, as I intended to have my 5 inspected and perhaps protected this summer, so I need to know the best treatment.
If you have bought a 9 year old car there is a fair chance that the underside is already looking very rusty, unless it has never been used in the rain. There is little you can do about this, but slapping a load of wax based stuff on it will hide it for a bit (and potentially make it worse if the wax coating is compromised, allows water in, then doesn’t let it out again). The stuff on the underside that looks the worst is normally cosmetic only, and I wouldn’t bother doing anything about it. There is something to be said for some sort of protection on the wheel arch lips if they haven’t started going already.
What you need to be concerned about are hidden sections rusting through, e.g.
If any of this is already happening, no amount of cavity wax or underseal will help you. Many garages will still happily take hundreds of pounds off you for “peace of mind” however.
If the car is new/immaculate condition, I would get the cavities protected with Bilt Hamber products (personal preference based on effectiveness I have seen vs. Dinitrol) and if under-car prettiness is something that matters, put something on there as well. If it’s already rusty, then normally it’s not worth the bother.
When I bought my MX5 last April I was horrified at the state of the under body which as it turned out wasn’t as bad as it looked and mainly confined to the front & rear suspension. Wheel arches, wings & doors were perfect. The original black rubberised under body was largely intact apart from slight peeling along the inner cills and chassis rails previously damaged by jacks, axle stands or whatever.
Here’s what I did. As the brake discs needed renewing anyway I removed the wheels, plastic wheel arch liners and gave everything a thorough power wash. When dry, gave everything a scrub with a wire brush followed by 2 coats of heavy duty industrial rust converter used on steel structures, bridges etc. which made things look better in itself. The brake calipers were so heavily scaled they needed a hammer and cold chisel to get down to bare metal. The wheel arches received 2 coats of waxoyl brush on under seal, the rest 3 coats of black anti stone chip aerosol. This operation (including new discs & pads) took the best part of 4 days before the weather turned foul and work stopped. I still need to waxoyl inside the cills, doors and box sections when the weather permits.
It’s hard dirty work and being a tight fisted Yorkshireman I begrudge coughing up £300 - £400 and being without a car for x days letting a garage do the work. Past bad experiences with garages makes me not trust them. I’m one of the “If you want a job done properly, do it yourself” brigade…assuming one has the skills, time and inclination of course.
Picking up my 2016 sport nav tomorrow. My current mk 2.5 has suffered badly from rust though I must admit I haven’t given it the attention it deserves due to family issues. Really want to look after my new sport nav and learn about doing the small maintenance jobs myself(complete novice). Should I get the Full Monty now to get maximum benefit? How long does it last? I live in Scotland, car will be used daily and not garaged. Could anyone post a link to general maintenance tips please. Looking forward to being a more involved member now life has quietened down. Thanks in advance