Hi Donal,

You've not specified any make or model, so we'll give you some generic advice. 

- Ask to see the car when its engine is stone cold, so you can see that it starts easily and that there is no excess smoke from the exhaust.

- Make sure that the DPF warning light turns on when you turn the ignition, but then quickly goes out when the car is running - same for all other warning lights.

- Dip the oil and make sure it looks clean. Same for the coolant in the radiator (do this when the car is cold).

- Let the car idle with the interior heating set to cold to ensure that the engine doesn't overheat.

- Check every electrical switch and sub-system, including the air conditioning and lights etc.

- Take a look under the car and under the bonnet for any signs of oil or coolant leaks.

- Test drive the car on a variety of roads and road surfaces, listening out for unusual noises from the suspension or engine. Do not have the radio on during this. Bring the car up to speed, preferably on a motorway, to ensure the power delivery is as expected and the car feels stable.

- Inspect all the tyres for signs of uneven wear or damage.

- Make sure you do all this when there is good daylight and the car is clean and dry.

Finally, if the car drives well, has a good service history, ticks all your boxes and appears in good order, before you hand over a deposit, get a full history check with Cartell.ie, as it will show up discrepancies in the mileage, whether any finance is outstanding or if the car has been written off.