Road Salt Can Fail Your MOT — Here’s What It Does Underneath Your Car

Salt-driven corrosion can strike anywhere… and it gets expensive fast

That right there is road salt — and it’s one of the biggest reasons vehicles rust faster in winter.

You might not notice it at first, because most of the damage happens out of sight… underneath.

But once corrosion takes hold, it can go from “a bit of surface rust” to serious structural issues — and in some cases, an MOT failure.

Let’s look at what salt really does to the bottom of a car, and why it’s worth protecting early.

The real effects of salt: an MOT failure

Here’s a perfect example of what winter salt can lead to.

We can see an MOT failure, caused by corrosion that’s become so severe the tester had no choice but to fail it.

That’s the thing about rust:

It doesn’t care where it strikes.

It can hit:

• the floor pan

• a subframe

• sills or chassis sections

• mounting points and structural areas

And once it starts weakening metal, it stops being cosmetic and becomes a safety issue.

Why this is more than just “a bit of rust”

Rust leads to structural weakness when left untreated.

And if it gets worse, it can turn into:

• holes in panels

• weakened structural sections

• compromised mounting points

• safety concerns

In this case, the vehicle has failed its MOT — and now it needs welding.

That means time off the road, labour costs, and the kind of bill you never wanted in the first place.

What causes it? Salt + grit + moisture

Winter roads are often covered in a mix of:

• salt

• grit

• wet slush

Every drive sprays that mixture into hidden seams and underbody areas, where it can sit and do its damage repeatedly — day after day.

That’s why winter corrosion can ramp up so quickly.

The simple solution: protect it before it starts

If road salt and grit are what drive corrosion, then the best approach is stopping it early — before you’re facing an MOT fail and a welding job.

With Lanoguard, you can cover vulnerable areas and help keep corrosion at bay.

✅ Covers the underbody and hard-to-reach areas
✅ Helps protect metal from winter salt exposure
✅ Ideal before (and during) gritter season

Protect your car now — before it becomes a repair job

Salt damage is preventable. But once corrosion becomes structural, it gets expensive fast.

Discover Lanoguard protection — available now.

Protect it now. Save money later.