V reg Escort alloy question - leaking air?

[MiniMac]

Posting a Q from my dad,

His escort seems to be leaking air at an absurd rate on all 4 tyres. As in, having to top them up once every 5 - 6days on one wheel and once every 10 on the rest. And thats even if the car is stationary. I've wondered whether they need reseating on the alloy, but Dad reckons that all alloys become 'porous' after a while

I've got a Fiesta the same age, how can a metal suddenly develop tonnes of holes?!

PH, I salute your knowledge!

[Jon GT2]

It sounds like corrosion on the inside of the rim where the tyre bead sits,you will need to get the tyres removed to check this.A good clean up of the rim and some extra thick tyre paste should cure it.