There are great tomes of complex information written about about engine oil and understanding all the various grades, codes and specifications, but thankfully buying the correct type of oil for your car is actually very simple indeed. There are 2 simple methods of finding the right oil for your car.
Method 1: Find your owners manual & lookup the correct oil spec.
Your owners manual (usually located in the glove box) will tell you what specification of oil is recommended for your car. Flick to the index at the back of the manual and look up 'Oil' or 'Engine Oil'
The way that vehicle manufacturers choose to display this information varies so we've included a couple of examples below, one from Peugeot and one from BMW. The BMW manual (on the left) lists a couple of specifications for its petrol and diesel engines. We'll concentrate on the diesel engines for the purpose of this example.

As the manual states, any of the oil specifications listed below are suitable for this BMW:
- BMW Longlife-01
- BMW longlife-04
- BMW longlife -98
- ACEA A3
So if you're browsing engine oil in a store or online you need to find a product that has one of the codes above on the back of the packaging or in the product details page on a website. The Castrol Edge oil pictured below meets the BMW longlife-04 specification listed in the BMW manual and is ok to use.

The Peugeot owners manual actually lists product names rather than specification codes. The manual states that for diesel engines in the UK and Ireland you can use:
- Total Quartz Diesel 7000 10w40
- Total Quartz 9000 5w40
- Total Quartz 9000 5w30
So you simply need to search for this product online or in-store. Simple!
Method 2: Use an online 'oil finder' to search the correct oil for your car
Like the one on
MicksGarage.com simply enter your car reg or select the make, model and horsepower from the drop down menus and hit GO! The finder will only show you oils which are suitable for your car.

In addition, most oil manufacturers such as Castrol or TOTAL have their own online 'oil finders' which work in exactly the same way. The handy thing about this method is that the amount of oil your car needs (in litres) will also be displayed.
Click here to use the TOTAL oil finder or
click here to use the Castrol oil finder