The Clio Williams is closely based on the 16v, so theres not much more to check apart from the authenticity of the car itself (someone else will have to detail what to look for there.
Overall, Im of the opinion that Williams owners are of the demographic that look after their cars well. However, the cars are fairly maintenace-intensive, so, as ever, the care it has received thus far will usually dictate condition. Look for a big folder of bills.
What you should then be looking for then can be split into categories:
Exterior:
- Rear arch lips are susceptible to rusting, front ones are plastic so arent a problem. Rust also possible on door bottoms, around window rear quarters and boot bottom. Rear arches are now only available as an entire quarter panel - £330 from Renault inc VAT each side - so make for an expensive repair. Other body panels are surprisingly reasonable after a recent price cut.
- Front fogs (expensive) are prone to cracking due to stone chips.
- Bonnet and front bumper also prone to stone chips.
Mechanical:
N.B. due to engine size, many otherwise simple jobs on 16v/Willy are engine-out jobs.
- Cambelts must have been done before 72k (many advise a cambelt change far earlier); fairly big bill in itself and mega bill if it snaps in service.
- Diffs, gbox and clutch are all expensive jobs so check carefully. Jump off the accelerator in 2nd to see if it pops out, if so, then suspect the box or the "dog bone" engine-to-subframe engine mount.
- Rear brake callipers can seize. New rear discs also necessitates new wheel bearings.
- Check aftermarket exhaust mountings - often a poor fit; rumbling under load can be caused by poor exhaust manifold to downpipe gasket (cheap job, disturbing noise).
- Erratic idle commonly due to faulty throttle potentionometer or idle speed control valve (respectively a specialist job and a straight swap).
- 16v/Willy run hot, so check coolant system - hoses, rad, expansion tank, water pump, anti-percolation (if you can). Radweld works wonders with minor radiator leaks.
- Engine mounts often go - embarassing and expensive to have your engine fall out, so see if engine rocks back and forth by opening bonnet and pulling accelerator cable.
- If car has induction kit check security of air hoses - can explain erratic idle or apparent air leak.
- Steering racks and columns are common failures. The handling reaction will be a second or two behind steering input in such a case; car will also tramline and follow road too much.
- Check for snapped front springs.
- CV gaiters should be checked - manifested by clicking noise on full lock.
- Handbrake is normally not good.
- If lowered, will need new front strut top mounts sooner or later. If majorly lowered, check to see that brake pressure-regulating control valve has been adjusted at the rear - otherwise the back wheels will lock too easily. Lowering also places extra strain on front anti-roll bar mountings and bushes and the track rod ends.
Interior:
- Sunroofs leak (only a problem on Williams 3 if specified).
- Electric window and mirror (not on Williams 1) switches are very expensive - so check them too.
- Front seat belt reels often become ineffective - especially the drivers one.
- Door handle rods in door mechanism can come loose, so that the handle wont work. A time-consuming but easy job.
