To undercoat or not undercoat the GEN4

Our mk4 is a year old. There is noticeable surface rust forming on the rear beams and other areas. Do I take it to Suzuki and try to get them to do something about it or just get it treated professionally?

If you're keeping it like forever
and have spare money
then get in touch with these guys
www.buzzweld.co.uk/
Possibly the best in the UK

I've just used a can of this filthy stuff purely as an experiment. Not on Gen4 but a steel decked lawnmower. I couldn't imagine applying this to the underside of any car and really can't think of a good use for it. In the interests of a balanced review clean up is easy (white spirit).
Chris

I would strongly advise against using any bitumen or rubber based underbody coating.

Such types of coatings have a tendency of cracking and/or delaminating from the surface and trapping the moisture behind which will rapidly digest the metal while this coating keeps the illusion of the area being in pristine condition ... until you poke a hole through it with a little finger one day.

Waxes are much, much better in this regard, but they wash/scrub off rather easily.

Some manufacturers make a combination of bitumen and wax, which is the best of both worlds, but still carries a bit of each world's weaknesses.


There are also various synthetic resin based underbody coatings, which widely warying robustness and performance characteristics, depending mostly on price ...

In any case, proper preparation is 80% of this type of work.

My 2007 (90000 miles) Jimny has finally failed it MOT very badly due to rust., body mounts, sills, around the headlights and the mounts under the headlights and more. It’s had a very hard life having been used off road a great deal. However I’ve just bough another 2011 50000 miles which is in good order with very little rust underneath and I’m thinking of having it sealed or some form of treatment to try and prolong its life.
I happen to have a gallon of hammerite paint in the garage which I’m thinking of using in the obvious/usual places which if nothing else may prolong the body mounts areas and sills.
You advise is much appreciated.
Bryn

Anything that you do is better than doing nothing especially if you have a good example to start with. As is often said preparing to a high standard is the key to a lasting job as increasingly the readily available products are becoming less and less effective over time, unless you have very deep pockets and get a professional refurbishment.