Servicing your Ford Focus RS Mk2 is important and one of the biggest things to do during servicing is to replace the engine oil and oil filter. It is important to make sure you use good quality oil in your Focus RS Mk2 and that it is topped up regularly. Failure to use the correct oil and to not change it frequently can reduce the life of the engine inside your Focus and lead to component/engine damage.
In this short guide we have put together some information on what oil and oil filter to use in your Focus RS Mk2, and when to change the oil and oil filter as well. Additionally, we have also included a few more oil related questions as well.
Table of Contents
What Is the Correct Engine Oil Weight for a Ford Focus RS Mk2?
Below we have quickly outlined what the different numbers and characters of the oil classification system mean and how they impact your RS Mk2.
The letter and number combinations at the front of the “XW-XX” system indicates the viscosity of the oil at – 17.8 degrees Celsius (0 degrees Fahrenheit). A lower number here means that the oil will thicken less in cooler temperatures.
The two numbers at the end (XX) indicate the viscosity of the oil at 100 degrees Celsius and represent the oil’s resistance to thinning at higher ambient and operating temperatures.
If we look at a 5W-30 vs a 10W-30 oil, we find that the former will thicken less in cooler temperatures, but they should be roughly the same at operating temperatures. Alternatively, if we take a 5W-30 and compare it to a 5W-40 we find that the 5W-30 will thin out quicker at higher temperatures.
What this means for your Ford Focus RS Mk2 is that an oil with a lower winter viscosity (XW) is probably better for colder operating temperatures or environments. For those of you who are located in a really hot environment, an oil with a higher viscosity at 100 degrees Celsius may be a better option. However, this is just generalising and there are a few other things to consider as well such as the manufacturers recommended oil weight.
What Is the Best Engine Oil for a Focus RS Mk2?
According to Ford you should use a 0W-40 weight engine oil with the specification ‘WSS M2C937-A’ in a Focus RS Mk2. Some owners will use heavier weight oils for track use, but for just general driving it is best to stick to 0W-40 like Ford recommends. Additionally, you should use a good quality synthetic oil over a non-synthetic (dino) one.
Our Recommendations for the Best Engine Oil for a Focus RS Mk2
Below you can find some of our top recommended oils for an RS Mk2.
Castrol Edge 0W-40 A3/B4 Engine Oil – Best for General Use
This fully synthetic 0W-40 engine oil from Castrol is one of the most recommended for the RS Mk2 and it meets Ford’s WSS-M2C937-A specification. Castrol Edge’s 0W-40 A3/B4 oil will maximise the short term and long term performance of your car’s engine and it will be perfect for general use in a wide range of environments.
Motul 8100 X-Max 0W-40 Engine Oil – Another Great Option
Another excellent option for your Ford Focus RS Mk2 is Motul’s 8100 X-Max 0W-40 engine oil. Like the Castrol above it fully meets Ford’s WSS-M2C937-A specification and it will be perfect for most driving conditions and environments. Motul is one of the most trusted brands in the business, so you know you are getting a good quality oil.
Castrol Edge Supercar 5W-50 Engine Oil – Good for Heavy Track Use
While the two 0W-40 oils above are good for general use and light to moderate track use, you may want to use something like Castrol Edge’s Supercar 5W-50 engine oil if you plan to do heavy track use. This is probably the heaviest weight oil you want to use in a Focus RS Mk2, however, some owners do use even thicker oils.
Oil Service Interval for the Focus RS Mk2
You will get a range of different answers from different owners on when to replace the engine oil, but Ford recommends doing it every 20,000 km (12,500 miles) or every 12 months. Many owners like to change the engine oil in their Focus RS Mk2s much more frequently than this with a common recommendation being around the 12,000 km (7,500 mile) mark, especially as these cars are getting on a bit now.
For those wondering if their Ford Focus RS Mk2 can go a bit further between changes, we recommend that you send the old oil off to a laboratory where its condition can be assessed. The lab will then be able to tell you if you can go further between changes or if you need to make changes more frequent.
How Much Oil is Needed for a Ford Focus RS Mk2?
There is a bit of conflicting information on how much oil one of these cars with some recommendations being 5.8-litres while others state around 6.4-litres with a filter change. We recommend starting with 5.8 oils and then topping up as necessary. If you run your Focus RS Mk2 with too little oil it can cause problems, so make sure it is topped up correctly!
Best Oil Filter for a Ford Focus RS Mk2
There are louds of different oil filters available for the Focus RS Mk2, but the OEM oil filter with the part number 6G9N 6744 BA is often the most recommended. Aftermarket options from the likes of Purolator will work as well, just make sure they are suitable before purchase.
When Should the Oil Filter Be Changed on a Focus RS Mk2?
It is usually recommended that you change the oil filter in a Focus RS Mk2 with every oil change. Oil filters are cheap to purchase and overtime the filter material can break down.
If you want to know more about any common problems with the Ford Focus RS Mk2, or if you are interested in buying one, check out our buyer’s guide here.
