Battery with temporary water cover. [Which has become permanent!]   Ensure the negative contact on the chassis is metal bright. Spray with WD40 to keep off rust. Securing clamp on the battery should be clean, and covered with grease. Try not to get grease on the battery post to metal clamp contact. Ensure the battery cells are topped up. They can take over a litre of distilled water.
Ensure all debris, leaves etc, is clear from the vent inputs above the radiator expansion container.