Rust and the APK (MOT): when does rust mean a fail?

Rust on your car looks bad, but not every rust spot is a problem at the APK, the compulsory periodic vehicle inspection in the Netherlands. The inspector mainly looks at rust that has gone right through the metal, in parts that keep the car strong. This article explains how the RDW, the Dutch vehicle authority, assesses rust and which repairs do and do not count.

By the team at Autobedrijf Willemsbrug, RDW-approved APK (MOT) test station since 1979 · Updated 4 November 2026

Our score is 4.8 / 5 from 235 reviews. Read what our customers say

Book an APK

The short answer

At the APK, rust is a fail if the metal has rusted away through its full thickness and the damage is greater than 2E. That limit applies per part, per mounting and per section of the floor pan. The inspector multiplies the percentage of rust damage by the rust damage grade of the part from the RDW APK manual. Rust that is only on the surface is not rust damage, but the inspector does fail sharp edges or parts that could come loose because of rust.

When does rust lead to a fail at the APK?

Rust is a fail if it puts the strength of the car or of a mounting point at risk. The RDW APK manual (APK-handboek) says that the load-bearing parts of the body must not have breaks or cracks. Nor may they be so corroded that the rigidity and the strength are at risk.

Most passenger cars have a self-supporting body, also called a monocoque. This means that the floor pan, the sills and the members together form the chassis. There is no separate frame underneath. For these cars the rule is that a part, a mounting or a section of the floor pan must not have more rust damage than 2E. We explain below what this 2E means.

Can be a rejection point: rusted-through spots in the sills, longitudinal members, cross members, floor pan and wheel arches, and rust around the mountings of parts such as the suspension and the engine.
Is a rejection point: cracks or breaks in load-bearing parts, sharp parts on the outside and parts that could come loose because of rust.
Not rust damage under the standard: rust that is only on the surface and has not gone through the full thickness of the metal.

What is the difference between surface rust and rust damage?

Under the RDW rules, rust damage is material that has disappeared through its full thickness because of corrosion. So there must be a hole or a spot where the metal has been eaten away. Surface rust is rust on or right under the paint. The metal underneath is then still intact.

Surface rust therefore does not count in the calculation. Even so, it is sensible to deal with it. Rust spreads, especially under bubbles in the paint and in places where dirt and salt stay behind. What is a brown mark now can become a hole later.

Type of rust	What you see	Effect on the APK
Surface rust	brown discolouring or bubbles in the paint, metal still solid	not rust damage under the standard
Pitting	deep pits in the metal, not yet through	not yet rust damage, but a point to watch
Rusted through	a hole, or metal that crumbles or gives way	rust damage, the inspector calculates the extent

Based on the definition of rust damage in the RDW rules (Additional permanent requirements, article 4).

How does the inspector calculate with the 2E rust limit?

The inspector multiplies the percentage of rust damage by the rust damage grade (in Dutch: roestschadegradatie) of the part. The grade for each part is listed in the APK manual and is expressed in E. An important load-bearing part has a high value, a panel that carries little load has a low one. The result must not be higher than 2E.

Part (self-supporting body)	Rust damage grade
Front longitudinal member	8E
Section of the floor pan	8E
Engine mounting (total)	8E
Wheel arch	8E
Main longitudinal member	6E
Main cross member	6E
Front door pillar	6E
Sill	6E
Door panel	1E
Bonnet	1E

Source: RDW APK manual, annex 1 (rust damage grades, no fully load-bearing chassis) and worked examples of rust damage.

How the percentage is determined depends on the part. For a member, the inspector looks at the part of the circumference of the cross-section that is affected, and at the length of the damage compared with the length of the member. For a section of the floor pan, the affected surface area and the length of the damage along the edges count. The highest percentage applies in each case.

Worked example from the RDW: a front door pillar has grade 6E. In the lengthwise direction, 40 cm out of 100 cm is affected. That is 40%. In the crosswise direction, 10% is affected. The highest percentage counts, so 40%. Then 40% of 6E equals 2.4E. That is more than 2E, so the car fails.

The RDW’s worked examples also show that it differs per location. For a wheel arch (8E) with 15% damage, the result is 1.2E and the car passes. On a spring seat, rusting through is not allowed: a hole of 0.5 cm² is already a rejection point there. A hole in a panel with a low grade, such as a door panel, can still be a problem for another reason, for example because of sharp edges.

For a mounting, such as the mounting of a suspension strut, only rust within an imaginary line 100 mm around the mounting counts. The inspector estimates how much strength the mounting has lost there. Rust outside that line does not count for that mounting.

Where and how does the inspector check for rust?

The inspector (in Dutch: keurmeester) looks at the underside of the car from an inspection pit or on a vehicle lift. If in doubt, he taps the metal with a small hammer with a rounded or ball-shaped head, or he measures the spot.

Sills: the members under the doors. Moisture and salt easily stay behind here.
Wheel arches and suspension strut mountings: these places carry the weight of the car and get a lot of spray from the road.
Longitudinal and cross members: the members that keep the floor rigid, also at the front near the engine.
Floor pan: especially the edges and the areas under the mats, where moisture from inside the car can stay.
Suspension and engine mountings: rust within 100 mm around the mounting counts.
Hinges: the mounting of the hinges of the doors, bonnet and boot lid must not be seriously affected by corrosion.

Do you drive a car with a separate chassis, like some off-road vehicles and vans? That is called a fully load-bearing chassis. For these vehicles the RDW uses separate tables, including for the rust damage grades and the permitted reduction in the thickness of the chassis.

For an overview of everything else the inspector checks, see our APK checklist. How the APK works at our garage is explained on our page about the APK for your car.

When is rust on the outside of the car a problem?

Rust on the outside is a problem if it creates sharp edges or if a part could come loose. Under article 5.2.48 of the APK manual, a passenger car must not have sharp parts that could injure other road users in a collision. No part of the exterior may be attached, damaged or corroded in such a way that it could come loose.

A rusty wing with a sharp edge, or an exterior part whose mounting has rusted away, can therefore be a reason for a fail. That is separate from the rust limit for load-bearing parts.

Doors count too. Doors must close properly and open in the normal way from the inside and the outside. According to the RDW, a door that has been welded shut, glued, sealed with sealant or fixed with screws does not meet the requirement.

How must a rust repair be done to pass the APK?

A rust repair must give the part back its original function. The RDW accepts two types of repair.

Made-to-fit pieces of sheet metal that are properly welded to the original material.
Replacement of the part. The new part is properly welded, or fixed with bolts if the original part was attached with bolts or rivets.

The RDW also sets requirements for the weld. Stitch welds (in Dutch: kettinglassen) must cover at least 50% of the circumference of the welded part and be spread evenly over that circumference. Plug welds, also called hole welds, have a diameter of at least 4 mm and are no more than 20 mm apart. Another method is only allowed if the manufacturer’s documentation prescribes it and the repair has been carried out according to that instruction.

According to the RDW, the inspector assesses a repair that does not meet these requirements as rust damage, unless shown otherwise. The extent of the repair then counts as the extent of the rust. A hole that has only been filled with body filler, sealant or polyester does not meet these repair requirements.

What do you do if rust is on the inspection report?

First read which point is on the report and whether it is a rejection point (afkeurpunt) or an advisory point (adviespunt). Our article on rejection points, repair points and advisory points explains the difference. An advisory point about rust is a warning: the car has passed, but the spot needs attention before the next inspection.

Would you like to know where the rust is and how serious it is? Ask us after the inspection. Then you can decide for yourself what it means for the value of the car and the next APK. If your car has failed at our garage, our page on a failed APK explains the next steps.

Want to prevent rust? In winter, rinse the underside and the wheel arches regularly to remove road salt. Have paint damage and stone chips touched up in good time. You will find more tips in our winter checklist for your car. Do you have a question about rust on your car? Call +31 10 479 00 00 or walk in without an appointment for a quick check.

Frequently asked questions

Will a car with small rust spots on the paint fail the APK?

No. According to the RDW, rust that is only on the surface is not rust damage. The inspector only counts it once the metal has rusted away through its full thickness. A sharp edge or a part that could come loose is a reason for a fail.

May I fill a rust hole with body filler or sealant?

No. Filler or sealant does not count as a repair at the APK. According to the RDW, a rust repair must be welded or done with a new part. The inspector assesses any other repair as rust damage, unless shown otherwise.

Does rust in the sills count at the APK?

Yes. In the APK manual the sill has a rust damage grade of 6E. For rust, cracks or breaks, the inspector only assesses the sill itself. For a dented sill, he checks whether the rigidity of the whole body is at risk.

Does the inspector use a hammer to check for rust?

Yes. The inspector looks first, with the car over a pit or on a lift. If he is in doubt, he taps the metal with a small hammer with a rounded or ball-shaped head, or he measures the spot.

Can a welded rust repair pass the APK?

Yes. The RDW accepts made-to-fit pieces of sheet metal that are properly welded to the original metal. The weld must meet the requirements, such as stitch welds over at least 50% of the circumference or plug welds of at least 4 mm that are no more than 20 mm apart.

Does the same rust limit apply to a car with a separate chassis?

No. For a fully load-bearing chassis, as on some off-road vehicles and vans, the RDW uses separate tables. These include the rust damage grades and the permitted reduction in the thickness of the chassis.

Can rust at the hinges be a rejection point?

Yes. The mounting of the hinges of the doors, bonnet and boot lid must not be seriously affected by corrosion. Doors must also close properly, and the lock and hinges of the bonnet and boot lid must give a proper closure.

Sources

Not sure about rust on your car?

Book an appointment for the APK or walk in for a quick check. We will tell you where the rust is and what it means for the inspection.

You will find us at Boterdiep 11 in Rotterdam-IJsselmonde, close to Stadion Feijenoord (De Kuip). We work by appointment. For a quick question or check you can walk in without an appointment.

Nederlands? Lees dit artikel in het Nederlands.