A week of driving barely changes a car. A week of standing still changes more than you would expect. Whether you are travelling for a festival, a work trip, or just not using the second car, this is what happens while it sits, and how to make sure it starts when you get back.
The battery slowly slips
Modern cars are never fully "off". The alarm, the clock and the electronics all draw a small standby current. A healthy battery handles a week easily, but an older one can quietly drop below the level needed to crank the engine. Our guide on how long a car battery lasts when parked has a plan for longer trips.
The tyres lose a little pressure
Tyres lose air slowly whether the car moves or not, and a car resting on the same patch of rubber for a long time can develop temporary flat spots. Over a week this is minor; correct inflation before you leave helps, and a short drive usually smooths things out.
The brakes pick up surface rust
In humid weather or after rain, a thin layer of rust can form on the brake discs. It is normal and usually wears off after a few gentle stops, with some noise at first. Persistent grinding or vibration needs a workshop.
Moisture and the cabin
A closed car in humid weather can start to smell musty, especially if wet umbrellas, mats or clothes were left inside. Take them out before you go. In the monsoon, check that door and boot seals are clean so water does not collect.
Something may move in
This is the one almost nobody plans for. A parked car is quiet, warm after the last drive, and full of sheltered nooks, which makes the engine bay a good home for a rat. The longer the car sits, the more likely a rodent settles in and starts chewing wiring, hoses and the cabin filter. Some owners come back from a two-week trip to a car that will not start and a nest under the bonnet. Our guide to how rats find a parked car explains why idle cars are targeted.
Before you go: a five-minute checklist
- Clean the bay and cabin: no food, wrappers or leaves to attract or shelter rodents.
- Remove wet items: umbrellas, mats, gym clothes.
- Park smart: away from garbage, drains and bushes.
- Check tyre pressure: inflate to the figure on the door sticker.
- Switch off accessories: dashcam, interior lights, anything plugged into the socket.
- Arrange a drive: if you will be away more than a week or two, ask someone to drive it for 20 to 30 minutes.
- Set up a rat deterrent: so the bay is less inviting while you are gone.
When you get back
| Check | Why |
|---|---|
| Walk around and look under the car | Leaks, droppings, debris |
| Open the bonnet | Droppings, nesting material, chewed wires or hoses |
| Sniff the cabin and vents | A musky smell can mean a nest near the air intake |
| Start the car and watch the dashboard | New warning lights after a long park can point to chewed wiring |
| First few stops gently | Clears surface rust from the brakes |
If you find chewed wiring, don't keep driving. Follow our steps for what to do after rats chew car wiring.
For the rodent risk, the EchoRepel Car Rat Repellent runs on its own while the car is parked and is designed to keep the engine bay unwelcoming to rats while you are away. For festival trips in particular, see leaving your car for the holidays.