Cleaning the underside of your car

Keeping the underside of your car clean probably one of the most essential things to keep on-top of, especially in the winter. Basically when dirt builds up underneath your car it absorbs the salt that is used to de-ice the roads, this salt then attracts water and can lead to corrosion and eventually rust. Often this is an area we miss when cleaning our cars and it can lead to some of the most serious issues.

This isn’t a big job and takes roughly 20 minutes, so I tend to do this bi-weekly during the winter and bi-monthly during the summer. I do recommend using a chassis cleaner for convenience and concerns of the high pressure from a regular lance potentially damaging the sealant on the underside of your car, however it works fine provided you take care and it is better than leaving it uncleaned.

Karcher Chassis Cleaner underside of vehicle

What’s needed to clean the underside of your vehicle:

  • Pressure Washer
  • Chassis Cleaner attachment (Optional)
  • Jack/Axle stands (Optional)
  • Underseal (If there’s any damage)

So how do I keep it clean?

(Note: If using a regular lance, I’d recommend lifting your car using a jack or axle stands as it’ll make life easier. If you’re using a chassis cleaner it’s not required)

  • Spray the underside of the car in straight sweeping motions, overlapping each time as you work your way down to avoid missing any areas.
  • Check the surface for any missed dirt by running your hand across it and using a torch for those areas you can’t reach.
  • Check sealant for any signs of damage and repair where necessary
  • Use a wash and wax to go over it again (This is optional and I’d only do so if you’re certain the bottom of the car is spotless, I found doing this made future cleaning much easier).

Now that the underside of your car is clean you should be protected, be sure to check it every now and then just to check if you need to go over it again. Also be sure to keep on top of other areas like your wheel arches for similar problems, even if you have a plastic lining around the arch it will help protect the metal surrounding it.