Buying a car with corroded wheels

Viewed a car for sale four days ago at dealership (2007 plate). Only half the disc on each alloy wheel was corroded (1-2mm deep) in particular around the rim(s) leading me to assume that the car had been left standing in water (or worse, salt water) for some time.

1) Is my assumption correct?
2) What are the ramifications of purchasing a car that has 'possibly' sat in sea water (or any water for that matter) for some period of time?
3) What should I ask the dealer to check for and what assurances should he be liable to provide for (the question in 2) having been put to him?

Asked on 30 December 2011 by carbamboozled

Answered by Honest John
Depends on the car and the type of alloy wheel. If it has polished alloy wheels with a clearcoat then what you have seen is commonly caused by winter road salt. But you will have to budget about £60 a wheel to refurb them.
Similar questions
I bought a Land Rover from a local garage 20 month ago, after eight months an MoT was due, which it failed for chassis rot. I had it repaired which I thought meant the problem was corrected, however...
I have just bought (approx 1 month ago) a 59 plate Civic 2.2 CDTi from AC. I have just noticed a little bit of rust when putting some stuff in the boot today. It is when the roof ends at the boot, behind...
We recently bought a high(ish) mileage (80,000) two year old Golf Bluemotion from Car Giant supermarket. The brakes have always been a little squeaky, however after a 300 mile journey back from The Lake...

Ask Honest John

Value my car