I think that a contributory factor to the door tops rusting is moisture trapped under the window scraper seal where it lies over the tops of the outer skin. Wherever water lies permanently on paint, it will find its way through, hence the importance of wax polishing the paintwork regularly. The wax doesn't just form a protective film over the paint, it also causes water to run off rather than cling.
The same problem afflicts Senators and Carltons where the front and rear windscreen rubber seal impinges on the outer panel skin.
I know nothing about rust on Omegas, but I've spent 15 years trying to stop it on Monzas, Senators and Carltons. Wherever two or more panels are joined by sealant, eg rear wheelarch, that is where rust will start. Where dirt and muck collects, in scuttles, tailgate shuts, bonnet shuts, etc, that is where rust will start. Where panels are joined by spotwelds with no sealant in between, that is where rust will start (eg rear chassis leg join). Stonechips and rubber seals trapping water over panels, that is where rust will start and spread under the paint.
The only answer is to flood the chassis sections, doors, sills etc with thin anti-rust wax which will seep in between the cracks and crevices. Waxoy is the most well known but I don't use it as it does not spray well. I prefer Dinitrol or trade waxes available from paint factors. It must be done in summer when the bodyshell is bone dry. It must be repeated in the most vulnerable areas every year preferably.
For the underside, it's rather uncoventional but we apply several coats of thin wax sprayed underneath and inside all the hollow sections, then when it has dried, two coats of black underseal.
It's a messy business which takes time to do properly and means stripping out door panels and so on to gain access. That's why many people don't bother. Accident repaired cars often have their new panels rotting out faster than the originals -nobody can be bothered to wax protect the inside and all new panels got from Opel (to end of '94 at least) was a thin coat of primer when new. Also, a sill full of wax, if it does start to rot, is a sure fire way to set fire to the car when the welding torch is applied.
I really hope I'll find that that Omegas are bucking the Opel/Vauxhall rust reputation of years past. Certainly my '98 Elite estate looks fairly solid, apart from the doors....
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Topic: Where do omega`s rust (Read 2332 times)