The NCT (National Car Test) is mandatory for all cars in Ireland that are four years old or older. While plenty of vehicles pass first time, the overall failure rate hovers around 50%. The good news is that many of the most common fail points are things you — or your mechanic — can catch and fix before test day. Here is your complete NCT preparation checklist.
Lights and Electrical
Lighting is one of the top reasons for NCT failure. Walk around your car and check every single light:
- Headlights — both dipped and full beam must work. Headlight alignment will also be tested, so if you have noticed your beams pointing oddly, have them adjusted.
- Brake lights — ask someone to press the pedal while you check from behind. Both sides and the high-level brake light must illuminate.
- Indicators — front, rear and side repeaters. They must flash at the correct rate (too fast usually means a bulb has blown).
- Fog lights and reversing lights — often overlooked but tested at the NCT.
- Number plate lights — must clearly illuminate the registration plate.
Tyres and Wheels
Tyres are another frequent fail point. The legal minimum tread depth in Ireland is 1.6mm, but aim for at least 2mm to be safe on test day:
- Check tread depth across the full width of each tyre. Uneven wear may also be flagged.
- Look for cuts, bulges or cracks in the sidewalls.
- Ensure all four tyres are the correct size for your vehicle and that they match in pairs across the same axle.
- Check tyre pressures and inflate to the manufacturer's recommended levels (usually found on a sticker inside the driver's door frame).
Brakes
The NCT includes a brake efficiency test on a rolling road. Before your test:
- Listen for squealing or grinding when braking — this indicates worn pads or discs.
- Check that the car does not pull to one side under braking.
- Test the handbrake — it should hold the car on a slope and click no more than about five to seven clicks.
- Top up brake fluid if the level is below the minimum mark on the reservoir.
Under the Bonnet
Several under-the-bonnet items are checked during the NCT:
- Engine oil — top it up if low. Excessive oil leaks can cause a fail.
- Coolant level — check when the engine is cold. The NCT inspector will check for leaks.
- Windscreen washer fluid — fill it up. The washers must work on both front and rear screens.
- Battery — make sure it is secure and the terminals are clean and tight.
Bodywork and Visibility
- Windscreen — any crack larger than a two euro coin in the driver's line of vision will fail. Chips outside the swept area may be noted but not necessarily failed.
- Mirrors — both wing mirrors and the interior mirror must be present, secure and undamaged.
- Wipers — blades must clear the windscreen effectively without streaking or juddering. Replace them if in doubt — they cost only a few euro.
- Exhaust — check for excessive smoke, rattles or blowing. An emissions test is part of the NCT.
- Seatbelts — all belts must retract properly, latch securely and show no fraying or damage.
Pre-NCT Service: Worth the Investment
Many garages offer a specific pre-NCT inspection service. This typically costs between EUR 50 and EUR 80 and involves a mechanic running through the same checks the NCT centre will perform. They will identify anything likely to cause a fail and can fix it before you go. Given that a retest costs EUR 28 and the inconvenience of rebooking, a pre-NCT check almost always pays for itself.
Need a Pre-NCT Inspection?
Contact Blackwater Motor Works to book a thorough pre-NCT check. We will identify and fix any issues so you can pass first time.
Book a Pre-NCT Check