PSA were very hit and miss with galvanising and even the technical dept didn't know which vehicles were treated and which weren't. (I phoned the tech dept in Coventry to ask the question regarding a 2010 Relay and they couldn't tell me even with a reg number. Their eventual reply was that later Relays have better protection against rust than older models did - very non committal.)
There was no continuity with PSA. Each factory seemed to do it own thing. VW have done a better job of intergrating Skoda into the VW fold. PSA with its rebadging policy don't have the same control especially with the factories in Slovakia (C3) and the Czech Republic (Toyota in Kolin.)
Our Citroen Xsara's are galvanised and there is just a couple of rust stains at the panel joins along the back valance underneath the bumper behind the spare wheel. The Xsara Picasso has exactly the same floor pan as the std Xsara and is also galvanised dipped. But somehow there is an issue with the galvanisation reaching inside of the sills of the Picasso behind the front wheels. Most older ones have had the sill welded because of rust - an MOT failure.
My 04 plate Citroen Relay is rotting along the sills because the Italian Fiat/PSA factory's rust protection was a joke at best. They played the same game as Ford. All they expect from a commercial vehicle is 5 years, where private buyers expect a longer body life.
Its only since 2006 that the 'new' generation of Relays/Boxers/Ducatos are galvanised dipped. They also never publicize this as it would mean they admit that the rust protection they did on previous models wasn't good enough with the potential for warranty claims.
If it was up to the manufacturers, none of them would protect against rust. Its just the EU has stipulated that manufacturers have got to improve the standard of protection, so they are forced to.
So if you are buying something older, then you have to get it inspected by an expect before you sign on the dotted line.
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