The short answer
Dry the brakes first, then wash the underbody, wheel arches and radiator, check fluids and filters, look for new damage while the car is clean, and dry the interior. Salt water and mud need the most urgent attention, because they eat metal and hide faults.
Do
- Dry the brakes with gentle, repeated braking
- Wash the underbody, arches and radiator
- Check the air filter, oils and for leaks
- Dry the interior and the load
- Touch up scratched steel early
Do not
- Park a muddy car and leave it for days
- Aim a pressure washer at seals and electrics
- Ignore a milky diff or transfer oil
- Pack away wet gear
- Forget the spare wheel and the tailgate
In the first hour
- Dry the brakes. After water or mud, brake gently and repeatedly until they bite normally
- Remove loose mud and grass from the underbody, the arches and the radiator before it hardens
- Wash the underbody and arches, from the back to the front, with plenty of water
- Clear the radiator and condenser from the back with a gentle hose, never with a hard jet that bends the fins
- Wash the wheels and the spare, including the tailgate carrier
- Open the doors and boot, and let everything dry
The check
- Diff and transfer case oil: a milky look means water got in, so change it soon. See water crossings
- Air filter: look for dust and wet, and replace it if it is clogged
- Leaks: look under the car for fresh drips
- Steering and suspension: look for bent or loose parts
- Tires: look for cuts, bulges and stones in the tread, and reset the pressure
- Underbody guards and bolts: check they are tight and not cracked
- Lights and wipers: make sure they work
Interior and gear
- Take everything out, shake out the sand and dust, and vacuum the carpets
- Dry wet seats and mats fully, or mould will follow
- Dry the tent, tarp and bedding completely before packing them away
- Wash the cooler and water containers, and leave them open to dry
- Clean and dry recovery gear, and inspect the rope
Salt and rust
Salt water and road salt are the worst. Rinse the underbody and wheel arches thoroughly the same day, and rinse again after it dries. Touch up any scratched or chipped steel with paint, and keep an eye on the chassis mounts and welds. See rust prevention.
Pick what you drove through
Tap the conditions to see where to focus.
Tap conditions (6 to try)
Focus after Mud
- Focus
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- Details
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Common mistakes
- Leaving the car muddy. It rusts and hides damage.
- Using a hard jet on the radiator. It bends the fins.
- Spraying electrics and seals. Water gets in.
- Ignoring milky oil. Water in a diff does damage.
- Packing wet gear. It rots and smells.
- Forgetting the spare. It rusts and gets dirty too.
A final word. Washing and inspecting a car involves water, heat and sharp edges. This guide is general information. Let hot parts cool first, keep hands clear of moving parts, and take the car to a qualified workshop if you find anything that worries you.