Underbody Protection

Technical Area Cleaning & Detailing
2

To anyone considering underbody protection I can wholeheartedly recommend the application of Dinitrol if done properly.

i have a nearly new MX-5 ND and intend keeping her for a long time. Concerned about the level of underseal from the factory (very minimal) and the UK winter climate and salt I decided to fork out and have the job done professionaly.

After considerable research I contacted my local approved Dinitrol agent (PB Customs near Oundle) and visited the premises to gain an insight into the process. I was very impressed with this business and the care they take in preparation of vehicles before applying the product.

All ancillary parts are either masked or removed and the products applied in a structured and unhurried way (I left my car with them for a week). The agent took photos of every step of the way and takes great pride in the work they carry out. The core of the business I used is preparation of vehicles for serious off-road excursions using rough tracks anywhere in the world (not just green leaning). 

The cost of all of this was quite expensive (around £900 all in) but I consider it well worth the expense and can vouch for the professionalism of the business I used. You get what you pay for in life but if you want the job doing well and not a simple bodge and cover with gunk approach then you have to pay.

To anyone considering this go for it especially as winter approaches. I have subsequently discovered that Dinitrol is used on aircraft, agricultural machinery and even off shore uses due to it‘s excellent resistance to salt corrosion.

Thoroughly recommended and does not affect Mazda warranty - I checked before proceeding. 

3

Post pictures up please, as there is a right and wrong way to do this on a ND underneath and did they do all the inner box sections also, Mazda have cut a lot out underneath and needs to be done right to make sure she does survive.

M-m 

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Every nook and cranny covered. Tried uploading pics but unsuccessful. More to life than spending all morning on forum following guidance so will try again at a later date!

5

You need to follow this guide to post pictures on the forum that others can see.

https://www.mx5oc.co.uk/forum/yaf_postst110647_New-Photo-Tutorial-2018.aspx

6

who did your dinitrol application 

7

How does this treatment compare to the service Krown rustproofing offer? Cheers

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How does this treatment compare to the service Krown rustproofing offer? Cheers

9

How does this treatment compare to the service Krown rustproofing offer? Cheers

10

Dinitrol applied by PB Customs near Oundle.

11

Basically, a number of companies offer rust proofing materials.

As each model of car is different and as each car is used in different locations no one has any real information if one particular brew is better than the other.

Underbody Wax will not by and large dry out but neither will it last say 10 years in areas that get direct water spray like un linererd wheel arches. Underbody Wax tends to an extent to self repair small scratches to its surface.

Stonechip has two advantages over Underbody wax it can take the punishment in un linered wheel arches and it tends to reduce road noise and dampen panel vibrations to a small extent. On the other hand it can after 10 to 15 years start to dry out and you will find if you go under a MK1 or Mk2 where a good 10% of the factory applied stonechip is disbonding from the underside of the car.

In all cases it is not fit and forget as the car needs to get on a lift every two years or so to touch up the rustproofing nothing more than 10 minutes work every few years.

Do not become a one product fan boy just get the car proteced and checked up once every few years just use a trusted applier nearest to you.

I have used Dinitrol Stone chip in aerosols and it was an easy apply, the same branded product from a compressor energised Dinitrol branded application gun at 30C clogged in the nozzle and Dinitol advised me that they sell the product but do not use it so could not suggest how to sort the problem.

12

PB Customs recommends an annual examination to ensure ongoing protection - this was explained to me before having the work done. A sensible option to ensure my car continues to enjoy a rust-free existence.
Probably needs to be compared to external paintwork on a house - should be fine for several years but will need re-application at some point to ensure protection remains in place.
A shame Mazda don’t apply much in the way of under body protection from the off especially for customers in colder and damper climates. However, I think the current ND model has less chance of rusting than the original NA model from what I have read.

13

 

Time will tell. As has been said so often they all were and still are thin gauge mild steel cars badly proofed and incapable of withstanding the rigour of salt, grit, flooded roads and contaminants.

Personally I’d not consider buying a pre-owned intended “keeper” unless it had been subjected to the sort of protection done as you have paid for, and the likes of IanH’s car.

Trust me, I know a bit about 5 rot!   

One thing, it seems, the Mk1’s have in favour is their front chassis rails last well (or better). My 25 years old rails are solid…single skin…although it’s rear arches sills both inner and outer require new metal.

Much depends on how they are used, and ownership care levels. Those on 3 year “hand it back” deals won’t bother and why should they? 

Changing days in 5 financing. The Last of the mid-60’s Fat Pension Baby-Boomer Mohicans abound and won’t flinch at chucking 10k plus in balloon payments on a suck it and see basis over 3 years, then chuck the keys in for something else…with cup-holders. 

Those who buy them with the intention to keep them long term with personal or car loans might take steps to stop them prematurely dissolving.

I’ve not got a lot of faith in Mk4’s or Mk3/Mk3.5’s lasting nearly 30 years.

Mind you they perhaps will not have to and could be legislated off the roads with everything by then!  

I’ve no evidence based reasons to imagine they will or should. 

Then again, I see plenty sub 10 years old so called prestige marques rotting merrily. 

Already solid & relatively rot free Mk2/Mk2.5’s are becoming a visual rarity around our highways & byways.

Still see bags of them at meets & shows though, but the best and most desirable are hardly what you would call daily hacks any longer.

It would be unreasonable given the passage of time to expect any more of them.