Under body treatment

[Richard9931995]

My 1995 993 looks in good shape so my question is not driven by a problem I can see, more a question of long term interest. Can anyone please advise me if I should think about having any underbody etc anti corrosion treatment carried out? As far as I can tell it has nothing done to it since it left the factory.

 

[geedee]

As no one has responded to your post as yet, I thought to jump in to share a bit of my own thinking, never having had the pleasure of owning or working on a 993.
There seems little doubt that paying attention to underbody areas can pay dividends in the long term, more so if a Porsche is driven in Winter months, or just occasional Summer rain, spends a degree of time in coastal areas, or spends most if not all it`s life being cosseted...? Even cosseted Porsches can corrode though generally at a much slower rate..
Keeping the underside clean in terms of identifying areas where the paintwork/underseal might seem to be more exposed to wear or damage and educating yourself as to where those might be would seem a worthy first step..?
Checking for and repairing paint wear or chips and possible underseal damage on a regular basis seems worthwhile.
Another likely area for corrosion to begin are locations where mud dust and general road debris/crud can build up and retain damp being held up against the bodywork, cleaning out these areas on a regular basis would also seem worthwhile.
Also that corrosion can begin from the inside of box sections and work it`s way outward while the underseal/paint shows no sign of that which is going on below can create an unpleasant surprise come MOT time..
There are ever areas prone to corrosion on any vehicle and that the 993 has been around for a few decades there will ever be those who have come cross them all and have shared their experiences on the www, thus perhaps worth spending a bit of time web wandering to learn where any such issues might be hiding on your 993..?
Link below as an example, I have zero financial involvement past, present, or planned in the future with this company which to the best of my knowledge has a good rep in the Porsche community..
https://www.precisionporsche.co.uk/993-chassis-legs

Good luck in your choices.

 

[DanC4s]

Have you heard of dry ice blasting? It uses CO2 crystals blasted at the car under pressure that removes dirt, oil and even underseal but not paint. This is what I'd be looking at in your position, check out The Blastsmith, costs are around £1200 I think

the blast smith dry ice blasting - Google Search

I've got no connection to the above other than I'd love to justify the costs for this on my own car!

 

[Gary Spalton]

hi, Richard, your thought chime exactly with mine. I have been a waxoyl fan for years, but it is quite messy and if it goes over brake lines you are likely to get an MOT advisory that the brake lines are covered and they cannot be inspected. My MOT guy has recommended a new product called Lanoguard. It is actually made from sheep's wool; ie. lanolin. It goes on really easily and thinly, is transparent, overspray is not a problem as it does not affect rubber. It's quite pricey, but I am planning to do my car this summer.

 

[geedee]

Dry ice blasting... I have seen the vids, all very impressive for one who spent many a decade nailing back together my corroded old Porsches and others.... A neighbour owned a rather special Nissan Skyline and was quoted circa £10k to bring it`s underside back to looking new if not better than new.
I suspect while cleaning surface grime off looks so much simpler and potentially less damaging with dry ice, in fact a good coating of old oil may have been reasonable protection in places that once cleaned away and exposed to the elements....?
Underbody coatings where the underside is blasted with some gunge may well just hide that which is going on below and in some cases exacerbate the process.
I suspect where possible keeping on top of chips and scratches on the original coatings may well have more appeal in the long term.
Ice blasting and full underbody strip down and refurb/replacement of components may not be best for a machine to be treated other than as a garage queen, concours entrant, or rarely used...Though defining rarely seems difficult..?
It might be best to consider the desired usage of one`s Porsche before seeking to create some sort of perfection, which is fine if that is one`s thing, though I suspect it might be simple to then make much less use ofit than prior to it`s make -over, perhaps becoming a slave to maintaining it`s perfect finishes...?
On the other hand I have an acquaintance who lives where snow lies for many months of the year, and he spends the winter months polishing everything metal till it gleams, then spends the summer months driving it like he stole it, and repeats the fettling process over the following Winter.
Each to their own...

 

[Richard9931995]

Many thanks for your replies. I'm going to do some more research using your thoughts and then decide which path to follow................

 

[Graham-S]

In 2020 (Covid times) I removed my rear bumper to fix the corner heatshield that had come loose.
Whilst there I removed the Bumper Support Bracket to the Chassis Leg and found rust and small holes!
After removing the Bumper main mounts you can then see into the chassis leg and the rust patches
Can't believe Porsche stuck two pieces of bare metal together and sealed around them!!
Was shocked as from the outside as all looked good. When cleaning up the metal the holes got bigger but luckily my neighbour welds and made a patch infill.
I used the Dinitrol products listed below.
I bought the long reach hose/pipe ext to get fully into the chassis leg so hopefully now will help protect going forward.
What was a quick little heatshield job turned into something more major! Luckily being lockdown couldn't really go anywhere anyway

DINITROL 3125 HS - 500ml Aerosol - 1 x 500ml Aerosol Can
DINITROL 4941 / Car - 500ml Aerosol - 1 x 500ml Aerosol Can
Dinitrol DIY rustproofing kits - DINITROL® Direct Official UK Site | Dinitrol Direct

Graham