Rainy Season Maintenance Checklist for Your Car

19 Apr 2025

The wet season is a testing time for vehicles, as, when driven in the rain, cars face a host of extra challenges. Moist air, slippery roads, taxing driving conditions- these elements place engines and vehicle components under additional strain. Fortunately, with proper preparation for the months ahead, you can protect your vehicle and avoid unnecessary and costly repairs. Here’s our comprehensive maintenance checklist to keep vehicles running smoothly and safely, even when driving your car in the rain.

What Issues Do Cars Face in the Rainy Season?

There are numerous ways in which the rainy season causes issues for cars:

1. Rust and Corrosion:

Many of a car’s key components are made of metal: the chassis, engine block, exhaust, wheels, body- the list goes on. Water is a surprisingly reactive substance. When water and oxygen in the air come into contact with metals like steel or aluminium, oxidation rapidly occurs, causing corrosion and rust. 

This chemical change turns metal into brittle metal oxides, at risk of crumbling and cracking. If left unchecked, rust and corrosion can quickly compromise the integrity of vehicle components. A well-maintained barrier of appropriate grease or car lubricant is the best way to protect metal car parts from the damaging effects of water.

2. Braking and Traction Issues:

Slippery wet surfaces increase the risk of skidding and cars hydroplaning, and brake systems can struggle to operate effectively. This is especially true if brake pads or rotors are worn. The chances of collisions and accidents can be significantly higher as a result. 

3. Increased Load on Engine and Wear on Tyres:

Wet roads reduce tyre grip, limiting the transfer of energy from the engine to the wheels. Water on the road creates resistance, forcing the engine to work harder to maintain speed. This decreases fuel efficiency and increases strain on the engine, potentially leading to greater wear on its components. Tyres also wear out faster due to the added workload.

4. Electrical Problems:

Rain seeping into electrical components can cause short circuits and compromise the performance of spark plugs and battery terminals. Damp conditions also make cold starts harder, particularly for older batteries.

5. Fuel System and Engine Waterlogging Issues:

Driving through flooding can potentially allow water to enter the engine or fuel system, which can cause severe damage or even engine failure.

6. Challenging Driving Conditions Increasing Risk of Accidents and Collisions:

Headlights can illuminate less effectively in heavy rain, and muddy or wet, fogged-up windshields compromise visibility further. These conditions can easily lead to road traffic accidents, especially when coupled with reduced grip on the roads. 

7. Grime and Debris Build-Up:

Wet, grimy sludge easily splashes up from the road’s surface onto the car’s undercarriage and wheels when driving in rainy conditions. Leaves and mud can also block drainage channels, allowing water to pool in critical areas of the car, such as around the bonnet, windscreen, or engine bay. Debris and accumulation of grime and dirt must be cleared frequently, otherwise corrosion and damage will occur over time.

With all these issues in mind, here are some strategies and approaches to protect your car from the worst of the rainy season.

Should I Dry My Car After It Rains?

Ideally yes, you should dry your car after it rains. Rainwater, and pollutants it collects when falling through the air, can all damage paintwork leading to water spots and rust.  To best protect your car’s exterior, it is recommended to dry it with a microfibre towel or blowdryer after rainfall.

What To Do If Rain Gets In Your Car

If rain enters your car’s interior, dry it promptly. Use a towel to remove standing water, then open the windows and use fans to aid evaporation. A wet / dry vacuum can help extract water from carpets and upholstery. To absorb remaining moisture, leave open boxes of baking soda or a portable dehumidifier on the backseat overnight.

Rainy Season Maintenance Checklist:

The benefits of regular vehicle maintenance are well-established. During the rainy months, maintenance is especially important, and is the best way to ensure your car is protected and functioning at its best. Here are the key vehicle components to keep an eye on:

1. Windscreen Wipers:

Your windscreen wipers will be working overtime to maintain visibility during the rainy season, so need to be fully functional. Cracks or stiffness in the wiper blades, or streaking on the windscreen when they are in use are all signs your wipers are beginning to fail. As a guide, wipers need replacing every 6-12 months, or sooner if they are showing such signs of wear. 

2. Tyres:

Tyres must work harder to maintain their grip on wet roads, so must be in good condition to meet the challenges of the rainy season. 

• Pressure:

Under- or over-inflated tyres experience reduced traction, so use a pressure gauge regularly to check tyre pressures are in the manufacturer’s recommended range.

• Tread Depth:

Tread depth is also integral to tyre grip. While a depth of 1.6mm is the legal minimum in most countries, a tread depth of 3mm offers far superior grip on wet roads. Consider replacing tyres if your existing ones’ tread is wearing down.

3.  Brakes: 

Wet roads make brakes work harder to slow or stop the car, and dramatically increase stopping distances. Test brake pads and discs at the start of the season, checking for any unusual sounds or vibrations. Check brake fluid levels, and replace frequently to prevent moisture contamination compromising its function. 

4. Headlights:

Fully functioning headlights are essential for you to see properly in heavy rainfall and for other drivers to see you. Check headlights, brake lights, indicators, and tail lights for non-functioning or dimming bulbs, and consider upgrading to LED or high-visibility bulbs for driving in heavy rain or fog.

5. Bodywork:

Paintwork is vulnerable to rust in wet conditions. Check for chips and scratches and have these repaired. You can also apply a coat of wax to the paintwork to create a protective barrier against the elements.

6. Fluid Levels:

Fluids such as engine oil, coolants, and windscreen washer liquids are essential to your car performing properly in any conditions. This is especially true when driving your car in the rain. Check levels and clarity, changing if dirty and topping up when necessary. 

7. Battery:

Cold weather that typically accompanies heavy rain strains your car’s battery. Check terminal connections and voltage levels, and clean off any corrosion with a specialised solution. Batteries over three years old, and ones showing signs of deterioration, should be replaced.

8. Undercarriage:

Accumulated debris, mud, and rainwater under your car can cause rust and corrosion. Have your undercarriage cleaned and remove dirt and grime regularly. An anti-rust treatment is recommended to offer additional protection through the rainy season.

9. Air Conditioning and Defroster:

Clearing condensation from windows is essential for maintaining good visibility during the rainy season. Run the defroster to clear fogged-up windows to test if it is functioning well, and check your air conditioning is fully operational.

10. Check For Leaks:

Leaks into the car’s interior can quickly lead to water damage. Inspect sunroof edges and seals on the windows to check for potential areas that might leak before driving in heavy rain. 

• What to Do If Your Car Leaks When It Rains? 

Dry out your car following our tips above, then find the source. Anything from faulty seals to blocked hoses and drains can cause leaks. Once the source is identified, it can then be mended and checked over by a professional.

11. Emergency Kit:

Not a car part, but an emergency kit can be a lifesaver in the event of a breakdown. Keep a small kit, including a flashlight, jump cables, a tyre repair kit, reflective triangles, a first aid kit, a blanket or warm clothing, a bottle of water, and an umbrella in the boot of your car in case of an emergency.

The challenges of driving your car in the rain are considerable, but don't be put off. By taking a proactive approach and following this maintenance checklist you can protect your car from the worst of the rainy season, and keep you and your loved one safe while doing so.

At Gulf Oil, we have over a century of experience keeping cars functioning at their best, whatever the driving conditions. To check your vehicle is ready for the rainy season, why not use our dealer locator to find your nearest dealership and book a service now?