Have the alloy wheels on our 2003 Ford Focus become porous, leading to loss of tyre pressure?

One tyre of my wife's 2003 Ford Focus gradually deflates from 30PSI to around 10PSI in the space of about a week. I have renewed the tyre and the valve twice but the problem persists. The tyre dealer can't find any fault with the alloy wheel but presumably there must be and it will have to be renewed? This would mean replacing all four wheels to obtain a match. Would I be safe buying secondhand?

Asked on 16 November 2013 by JM, via email

Answered by Honest John
Alloy wheels can become porous after a few years and 10 years is more than a few years. You could get a used set of steel wheels from a parts specialist or breaker, usually with used tyres still on: www.honestjohn.co.uk/useful-websites/parts-accesso.../. Or get a set of four 16-inch TUV-approved Alutec alloys with a 5-year guarantee for £335 from www.tyremen.co.uk. You have to inform your insurer of the ‘modification’.
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