Thaddeus

Hi,

I have seen a few threads on here about rust. I thought Porsche galvanized the sheet metal on these cars, so I'm curious.

How prone is the 993 to rust? Is it galvanized? If so, which parts aren't? Any spots I should especially check for issues?

thanks

Thaddeus

Porscheologist

My understanding is the entire body is galvanized steel. Galvanization does not guarantee rust prevention. It helps to minimize it. I believe the original Porsche warranty is for ten years or so but it's not forever. My 95 was a Washington DC car and it has nor rust issues on the body. What has rusted on my car is the cheap cadmium plated bolts Porsche used to cut costs in 95. Of course all the exhaust hardware has rusted. I have read about a few Targas having rust issues and even some coupes having rust around the windshield area and the rear window area. Buy a good Arizona or California car and you should have no issues. Of course have a good shop check for rust during the PPI. But don't just rely on that, crawl around and lift up windshield and rear window seal lips and floor mats. Look in nooks and crannys. Expect rust on the bolts but do not accept it on any body panels. Overall these cars stand up well to the elements. My 20 year old SC had no rust at all. Good luck!

Thaddeus

Thanks for the reply! Did they use any aluminum panels, e.g., the hood, to save weight at all?

Monique

Some panels are alu. I have a number including the bonnet, the engine lid and in my case the GT2 alu doors.

But these things were only fitted to RS's and GT2's ... sorry for you.

Thaddeus

Hm. Aluminum components were standard on 928's. SIKE!

Monique

Porsche had to put alu on the 928...it's such a phat assed car!

Thaddeus

Don't make me tell the 928 board what you folks said.... there's enough internecine conflict in the world...

SJB993

Hi Thaddeus,

Things which definitely do rust (see recent posts) are the steel hangers used to mount the rear bumper (or is it fender in The States?). There are four of these, but fortunately they are not big costs items. Just thought you might like to know about something else to check - some people have had consequential rattling and (as I did) droning sounds.

Steve.

sidned

IIRC galvanising only works if the paint is not scratched. As soon as a galvanised area is exposed, the chemical turns to dust and you have regular steel, so any scratches or areas prone to rubbing of grit (i.e. windsheilds) will lose the galvanised protection and start to rust.

trickydisco

So the frame/chassis/undercarriage is also galvanized?

993inNC

I think its zinc dipping that the factory does (ever since the 944 was introduced), not galvanized. And zinc is not really a good rust preventative......course its better than nothing. But I'm sure someone here will know more about it than I and chime in all in due time

Flying Finn

Galvanizing is achived by dipping the metal in sink.

Here's something to read:

From Porsche, regarding the outside protection of the car:

"More than 25 years ago, under German government auspices, Porsche demonstrated a distinctive-looking prototype at automotive exhibitions throughout Europe. It was publicized without a type number, instead using the simple designation Lang-zeit Auto — the Long-Life Car.

Among its features: a fully galvanized, multi-step finished chassis design with an expected bodyshell life of 20 years. The Lang-zeit Auto caused a sensation wherever it was shown, and prompted a great deal of discussion among Germany’s other automakers. Yet it was never introduced by Porsche in that form.

Rather, Porsche built lang-zeit principles into all Porsches. Every current Porsche, in fact, uses 100 percent galvanized steel for its monocoque. Galvanized steel is sheet steel that has been dipped or plated with zinc, acquiring a molecularly bonded coating on both sides. It has two interesting properties: First, its electrochemical characteristics cause the zinc to “migrate” to any area on the steel plate that is scratched — a metallic healing process. And second, when welded, the zinc condenses on the welded area, protecting it nearly as effectively as if it had not been welded. Galvanized steel is the first — and most important — line of protection for Porsche bodyshells.

But galvanizing is by no means the only protective coating. A 26-step paint process applies several additional paint layers to every Porsche, in precise thicknesses. An electrophoretic primer — one of three shades to match topcoat color — uses opposite charges to literally pull paint onto the bodyshell by electrical attraction, depositing more than three times as much primer as normal spray.

The final layers of paint are applied in a thin, and therefore resilient layer, with one compound of paint used for metal surfaces, another flexible paint for body-colored plastic parts. And all finishes are given a clear overcoat to maintain their gloss and stabilize their dimensional characteristics, for durability and good appearance even in adverse climates.

During these coating steps, the bodyshell is periodically subjected to drying ovens that bake the coatings into place. Hot wax is sprayed into body cavities, then allowed to cool to a flexible, corrosion-resistant layer that covers precisely those areas where moisture is most likely to collect. Resilient undercoating is applied to lower body panels and to the undercarriage.

The real proof of the effectiveness of these measures is to be found not on the bodyshell itself, but rather in the warranty book: Porsche warrants every car against rust perforation for a full 10 years. Plainly, Porsche’s confidence in its ability to bear full responsibility for corrosion resistance, even in areas of the United States with extended poor weather conditions and salted roads, is potent demonstration of the effectiveness of Porsche’s protective measures.

But a protective finish can only protect the body from the elements. To provide protection from accidental damage in parking lots, on city streets, and on dusty or stone-strewn rural roads, other forms of protection are integrated into a Porsche’s overall design. Front and rear bumpers are aluminum members supported by hydraulic struts that absorb impacts up to 2.5 mph with negligible damage. One-piece bumper coverings of a tough polypropylene/EPDM compound minimize the visual evidence of any contact; on the Boxster and 911 noses. They may be replaced by removing a mere six bolts.

Along the underbody and wheel wells, resilient paint and plastic sill panels help repel stones and dust without chipping. Rubbery steinschutz (stone-protection) coverings are adhesively attached to areas like the leading edges of the rear fenders, to protect against stone impacts. Porsche’s polypropylene underbody panels provide a benefit in addition to smoothing airflow under the car. They protect the metal bodyshell from damage resulting from sand, gravel and stones.

The large headlamp lenses of both the Boxster and the 911 are an impact-resistant plastic material, rather than glass. A quick-release mechanism makes bulb replacement quick — and easy. The alloy wheels are coated with a protective matte finish that resists the chemical degradation of brake dust and road salt. Mufflers, catalytic converters and exhaust tubes are composed of stainless steel. Even the gas filler neck of a Porsche is engineered for protection: opening the filler flap reveals a rubberized apron that protects the fender from the scratches careless station attendants or self-filling might otherwise cause. Porsche fuel tanks are made of polyethylene plastic. Not only is this material spark resistant, it cannot rust. Nor can the fuel lines: they’re made of aluminum."

993inNC

Okay, so I was right it is Zinc. They use galvanizing as a generic term. There are 2 types of galavanizing, and then there is zinc coating, but true galvanizing and zinc coated are technically 2 different things........I think is how it worked