Rust has always been a problem for cars in the UK, as it's caused by wet winters and salted roads.  

The longer the rust is left, the larger the bill will be. So, if your car shows signs of rust, it's best to get it sorted as soon as possible. 

Today, we're here to explain rust repair costs while answering some common queries about this problem. Read on to find out how much you can expect to pay and how to find a garage near you.

How much is rust repair on a car? 

The average rust repair costs around £360 for UK drivers.

However, costs can be anywhere from £200 for a patch rust repair, to £3,000+ for multiple panel replacement. The exact cost depends on the area, type of car, and extent of the rust.  

We’ve listed some common rust areas, their causes, and costs below. 

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What are the most common areas to rust? 

With cars having different shapes and designs, rust doesn’t always appear in the same place. Here are some five main areas you might find rust and how to spot them. 

1. Wheel arches 

Most areas most prone to rust are underneath the car, but the wheel arches are subject to more road dirt and grime than anywhere else. Wheel arches are often made up of an outer skin and an inner structural panel. 

Why do wheel arches rust? 

Wheel arches catch any dirt, water, and road salt thrown up by the wheels. Rust will appear even faster if the area has a coating of mud, as this holds moisture against the steel.  

We also mentioned how wheel arches are made; this sandwich of metal sheets is the perfect place for any moisture to pool; wheel arches often rust from the inside out. 

How much does wheel arch rust cost to repair? 

Repairs cost anywhere from £300 to £2000 per side. 

Rear wheel arches are pricier as they're integral to the car's bodyshell, while front wheel arches often need only a wing panel replacement, costing around £500. The high expense is due to the wheel arch being part of the car's main body, requiring specialist welding, bodywork, and painting for a like-new repair.

2. Sills

Another common place for cars to show rust is on the sills. This is the section of the floor between the front and rear wheels that makes up the bottom section of the door frame. 

Why do sills rust out? 

Road grime and water from the wheels hit the sills, but that's not all. Cars have drainage channels that direct rainwater through gaps between doors and into the sills.

If these drainage holes get blocked, water accumulates and causes internal rust. Regular maintenance and clearing of these holes can prevent rusting.

How much does sill rust repair cost? 

Sills cost between £400 - £1,500 for a rust repair. Since the sills are a structural component, they need to be repaired properly to pass an MOT.

Most cars have inner and outer sills. Severe rust on the outer sill likely means the inner sill will also need replacing with a welded new panel.

3. Boot floor 

A common theme is that trapped water causes most car rust issues, including on the boot floor and especially in the spare wheel well.

Rust in the boot is an easy and important check to do when buying a used car. 

What causes rust in the boot floor?

Standing or trapped water from boot leaks are the most common cause of boot floor rust.

What is the cost of repairing boot floor rust?

Boot floor rust repairs cost £250 to £800. 

This repair price is more reasonable, as the boot floor is not seen. However, the final cost is still affected by the extent of rust, your location, and the make of your car.

4. Exhausts 

Exhaust rust is a common MOT failure in older cars and should be fixed quickly to prevent fumes from leaking into the cabin.

What causes exhausts to rust? 

Rusty exhausts are common in older cars, leading to leaks and eventual detachment. The main causes are road salt/water and condensation.

While road salt exposure is unavoidable, condensation can be minimised by reducing short trips. 

Water condenses inside the cold exhaust pipe when parked, but long journeys allow hot gases to vaporise this water, preventing rust buildup from shorter trips.

How much does it cost to fix a rusty exhaust pipe?

Exhaust pipe rust costs £175 to £500 to repair, as most exhaust pipes are made from plain steel and not stainless steel.

Thankfully, exhausts are bolted to the engine and held by rubber mounts, making them easy for a garage to replace.

5. Suspension Components

Suspension arms, springs and shock absorbers are subject to road water, dirt, and salt. Older or high-mileage cars can experience higher levels of rust in these areas.  

What causes the suspension to rust? 

Though most wishbones, control arms, and springs are painted to prevent rust, suspension components often get hit by stones and debris. This damage, along with exposure to water and salt, makes them particularly prone to rust.

How much does suspension rust cost to fix? 

Most suspension rust repairs cost between £125 to £500. Like exhausts, suspension components can be unbolted and cheaply replaced.

What causes cars to rust in the UK? 

Rust occurs when iron, oxygen, and water mix together - a process called oxidation. 

Rust is a common issue for car bodies, suspension components, and any other car parts that contain iron ore. Water and salt accelerate this process, and cars in the UK are exposed to significant amounts of both.

Here are some common questions about rust and car rust repair costs. 

Is rust on my car dangerous? 

Depending on its location and severity, rust can seriously affect your vehicle's safety, particularly on suspension components, sills, and subframes.

Even minor rust on bodywork like wheel arches, roof, boot lid, doors, and front wings should not be overlooked. Addressing it promptly is a proactive step towards maintaining your vehicle's safety and longevity. 

Since rust is an ongoing issue, you should fix it promptly to reduce repair costs.

Will my car fail the MOT for rust? 

Cars will only fail an MOT if the rust is extensive and on a structural component (e.g. sill, subframe, or suspension). 

Similarly, rust on the bodywork within a specified distance of suspension mountings or seat belt anchorage points will also not pass an MOT. 

Can I fix car rust myself? 

If your car has surface rust, you can touch up specific areas at home.

Use rust converter paints on clean, rust-free areas to turn rust into a solid material and prevent further rusting. 

Professional welding is required for rust on structural components or inside-out rust. After applying the converter paint, the area should be finished with colour-matched paint and a top coat.

How to prevent rust on your car 

Rust requires ongoing preventative maintenance, ideally before it starts.

Undersealing, a protective paint applied to the car's underside, helps prevent rust by shielding bare steel from water. A similar product can be injected into sills and wheel arches.

When do cars start to rust?

Car rust can start at any time. However, it’s more common in older cars that have experienced more bumps and time on the road. 

Other factors that can cause a car to rust earlier include damage, climate, and the quality of your paintwork. 

What are the different types of car rust?

Most cars are affected by red rust. This occurs when water comes into contact with a contaminant or when paint damage exposes the metal.

Other types of rust include:

• Black rust - Appears when oxygen is trapped and is slower than other types. For example, this can appear under paint.
• Yellow rust - Forms when metals are completely submerged in water. This is unlikely to affect cars.
• Brown rust - Only forms when contaminants are left behind from the manufacturing process.

The takeaway - Ask an expert about rust repair costs

So there you have it: rust can present a big problem for car owners if it isn’t fixed. 

If you’re unsure how bad your rust problem is, ask one of our experts. Otherwise, your car might experience more damage than it needs to. It’s always better to get a professional opinion if you’re unsure!

How Bumper can help

With Bumper, you can split the cost of repairs into interest-free instalments. Apply online and choose from 1000s of garages and dealerships across the country. 

Author - Joseph Law

Joseph has been writing about cars for over seven years and writing for Bumper for over two, blending his passion for automobiles with a talent for storytelling.

Joseph has written about engineering and cars for Autozilla, Komaspec, and several engineering manufacturers. When he's not writing or tinkering with one of his five cars, Joseph dreams of owning an Alfa Romeo 33 Stradale.