Holden Commodore: Rust under the boot seal, in the spare wheel well and around the bonded screens (VN-VS)

VN through VS Commodores rust in a very consistent set of places: under the rubber seal around the boot opening, in the spare wheel well and under the boot carpet, along the lower rear corners of the front guards, the bottom of the boot lid below the number plate, the leading edge of the bonnet, and the expensive one - the cowl panel under the lower edge of the bonded windscreen and the surround of the rear screen. Water gets in past perished tail-light and quarter-window seals and sits in the boot floor, so the rot works from the inside out and looks perfect from above. Screen surround rust is a structural repair: the glass comes out, metal is cut and welded, and the screen is rebonded, and in New Zealand it is a warrant of fitness failure. VN paint was poor when new, so a repaint hiding fresh filler is common on survivors.

• Damp carpet or a musty smell in the boot
• Water sitting in the spare wheel well
• Bubbling paint along the bottom of the boot lid or the front guards
• Rust stains or blistering where the windscreen rubber meets the body
• Condensation or water inside the tail-light lenses

1. 1

   Lift the boot carpet and the spare wheel and look straight into the well with your phone torch, because standing water, damp underfelt or flaky brown metal there is the single most useful thing you will find on this car.

2. 2

   Run your fingers all the way round the boot opening under the rubber seal, easing the seal back with your fingers, and feel for rough or bubbled metal.

3. 3

   Look along the bottom edge of the boot lid below the number plate, the leading edge of the bonnet, and the bottom rear corners of both front guards for paint that has lifted or blistered.

4. 4

   Then look very carefully where the windscreen glass meets the painted body at the bottom corners and along the base of the screen, and do the same at the rear screen, because rust there is structural and fails a warrant of fitness.

5. 5

   Press gently along those edges with your thumb and listen for a crackle.

6. 6

   Check inside both tail lights for water or green corroded connectors, and ask the seller whether the car has ever been repainted or had rust cut out.

7. 7

   If a workshop inspection is possible: have the car put on a hoist so the boot floor, rear rails and sill seams can be checked from underneath, and have any suspect screen surround probed once the trim is out of the way.

$600 to $4,000 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

• “Has the car ever been repainted, and which panels?”
• “Has any rust been cut out and welded?”
• “Has the windscreen ever been replaced, and was there rust underneath it?”
• “Does the boot ever get wet after heavy rain?”
• “Were there any rust advisories on the last warrant of fitness?”

The failure described above is documented in the sources below. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them.

• WhichCar 'Buyer's guide: VN-VP Commodore & Calais'
• Trade Unique Cars 'Holden VN-VP Commodore/Calais' review
• Holdcom Auto Parts article 'Fixing Rust Issues On VS Commodore Parts'
• Unofficial Holden Commodore Archive (vaber.au) Technical Tips - boot and quarter-window seal leaks, tail-light water ingress