Which under-bonnet faults should I look for during a used-car viewing?

Look for fluid leaks, low levels, damaged wiring or hoses, signs of overheating, poor repairs and anything inconsistent with the seller’s description or service history.

In relation to “Which under-bonnet faults should I look for during a used-car viewing?”, no single green check proves a used car is a good buy; documentary checks and a physical inspection answer different questions.

For “Which under-bonnet faults should I look for during a used-car viewing?”, look for mismatched fluid levels, fresh cleaning around one area, brittle hoses, loose battery terminals and evidence of coolant or oil escaping. Do not remove a hot coolant cap.

For “Which under-bonnet faults should I look for during a used-car viewing?”, this answer is written for a Northern Ireland user, but some vehicle-registration, consumer-credit and insurance functions operate on a UK-wide basis. The attached sources — GOV.UK - Buy a vehicle: step by step, GOV.UK - Vehicle registration: new and used vehicles, and nidirect - Contact Consumerline — are therefore deliberately mixed where the responsible authority is UK-wide. That is more accurate than forcing every point into an NI-only source.

Practical next step for “Which under-bonnet faults should I look for during a used-car viewing?”: do not pay until this point has been independently checked. Save the advert, seller messages and any official or commercial check so you can show exactly what information you relied on.