Used Car Retailer of the Year 2023

020 8969 5511
Open Today: 9am - 7pm

What To Check Before Buying A Used Car

| In Buying Guides

When you are looking for your next used car, you will see a huge array of vehicles that will make picking the best one a tricky task. If you don’t know your cam belt from your dipstick then the following used car buying tips should help you pick a good quality second-hand vehicle that answers what you need. 

Take a look at our top 4 things to check before buying a used car.

1. Tyre Depth

car tyre tread

One important thing to check on any used car you are considering buying is its tread depth. Not only are well-worn tyres dangerous (they can drastically influence your car’s braking distance), but they are also illegal. 1.6mm is the legal limit for tire tread depth in the UK. If you are caught driving with tires that fall below this tread depth then you can be fined £2,500 and 3 penalty points per tyre.

The first of our used car buying tips is the 20p trick. This is a cheap and easy way to check the tire tread on a used car before you buy it : simply find the deepest tread on your tyre and place the 20p flat-side down into the groove. If you see can any of the outer edge of the coin then your tyres may be illegal, risking both a fine and an accident.

2. Oil Spillage

Next on what to check before buying a used car: the oil. It is expected that every car you look at will have some oil leakage visible over its engine when you lift the bonnet considering you are looking at a second-hand vehicle.

However, if there is an obvious excess amount then it could indicate a serious problem with the oil pump or gaskets. A real excess of oil can indicate that the car has not been cared for as well as it could have been and could suggest that the car has not been thoroughly inspected by staff.

3. Clutch

One common issue that manual transmission used cars can have is a worn-out clutch. So our used car buying tip to effectively check a manual clutch for slippage is to drive the used car over 40mph. This allows you to feel any slippage as you change gears. You can tell when this occurs when the revs go up but the performance stays the same. If this happens then make it known to the staff at the dealership and move on to the next used car.

4. DPF

Here’s what to check before buying a used car that has a diesel engine. Diesel cars have been required to have something called a DPF (Diesel Particulate Filter), a filter that manufacturers have been fitting since 2009. DPFs are used to limit the amount of soot that diesel engines produce. This filter collects particles of soot and to be effective, needs to be regenerated periodically. 

If the previous owner of a used diesel model does not regularly regenerate the vehicle, the filter becomes clogged up and does not function properly. You must check that the DPF warning light is not showing - if it is then it is a good indication that the previous driver has not been looking after their car.



The last of our used car buying tips refers to convertible models alone. Convertibles with soft-top roofs can have a problem that is unique to them: the sealing washers that hold the folding mechanisms in the roof can wear out and perish. This can cause damage to the inner workings of the roof and can of course allow water to leak down into the interior of the car and ruin the upholstery. So a simple check of these little washers can save you a lot of money and stress later on!


We hope these used car buying tips will be helpful as you search for your perfect second-hand vehicle. If you want to make the search easier, at Cargiant we do a full check on any cars that we sell so you don’t have to worry about anything. Take a look at our second hand cars for sale.