Thanks Johan, thanks for taking the time to respond. It seems you’re correct now that I’ve checked the online manual. I’ll need to recheck the paper manual when I get back into the UK as I’m sure I’ve seen it somewhere.I have never heard anything about any ball in there....
The manual states....
- Open the rear luggage compartment.
- Cayman: Turn cap counterclockwise and remove (Fig. 63).
- Carefully screw off the coolant reservoir cap and allow any excess pressure to escape.
- Unscrew the cap completely.
- Read the coolant level. The coolant level must be below the MAX marking. (no coolant level visible at base of standpipe).
- If necessary, top up the coolant to the MAX marking, do not fill above the MAX marking. Only use a mixture consisting of equal parts of freeze protection agent and distilled water. The MAX marking only applies during refilling itself as the level in the standpipe drops after the engine is first started.
- Screw the cap on the coolant reservoir closed until it is felt to reach the end stop.
The facts that you don’t have “a ball” either and neither does it state there should be one online gives me some comfort. I’ll recheck the manual when possible.