Bread Crumb Link
Castrol Logo
Opie Oils Logo

Approved Store

Oil Slider - FAQ Castrol / Opie Oils

Frequently Asked Questions

Delivery & returnS.

Why do we charge for delivery?

Due to the weight of oil, we have to charge delivery. To give you an idea, the weight of oil works out around 1 kg per Litre, that's roughly 10 times the weight of a CD (5 litres = 50 CDs!). However our delivery charges are very fair and we do not make a profit on carriage. This is to ensure our prices remain as competitive as possible.

How long will it take for my order to arrive?

We will aim to dispatch all orders within 1 working day of receiving cleared funds via PayPal (Monday to Friday). The vast majority of items are held in stock and dispatched from our UK warehouse. UK delivery will take less than 7 working days (i.e. Monday to Friday inclusive), unless we contact you to advise otherwise. In case of Bank Holidays please allow an extra working day.

We may list products which are not held as stock and are special order items. In this instance delivery times may be longer, but we will advise you within one working day if this is the case. Some items may have a specific delivery lead time stated in the description which should also be observed.

Which Courier do you use?

The vast majority of orders sent to UK destinations are sent via FedEx and UKMail. Smaller low value orders are despatched using Royal Mail.Deliveries will take place between the hours of 8 am to 6 pm. If you are out when the courier arrives, the courier will attempt delivery on the next working day and will leave a card to confirm.

FedEx and UKMail will normally attempt to deliver the item twice before returning the item to us. If your item is sent by Royal Mail and no one is in to take delivery, you will be left a card and your item will be held at a local Royal Mail depot for collection. Please ensure someone is present to sign for the item. Should the item be returned to us we will have to charge for re-delivery.

What is your Returns Policy?

Please see our returns information here.

How can I return items that I have ordered in error?

Please see our returns information here.

How do I get my Tracking No?

Once we are notified of the tracking number, then we will update the dispatch details accordingly.

To where can my order be delivered?

UK: We deliver throughout the UK including Northern Ireland, Isle of Man and Scottish Islands. As per ebay policy we can only send to the address that is entered on PayPal / ebay checkout.

We regret that our couriers are not able to deliver to PO boxes, university campuses and military bases.

International: The majority of items are available through the Ebay Global Shipping Programme. Information about the availability of the Global Shipping Programme to your country can be found on your local ebay site. Information about Ebay Global Shipping Programme on ebay UK

Oil Information

Why is one synthetic oil so much more expensive than another?

There are three types of synthetic oils; Hydrocracked, Polyalphaolefin (PAO) and Ester oils.

Hydrocracked oils are not really synthetic at all; they are highly refined and modified mineral oils that (due largely to the outcome of a landmark court case) can legally be sold as synthetic oils. All cheaper oils and the 'synthetic' component of part-synthetic or semi-synthetic oils are hydrocracked mineral oils.

PAO synthetics are genuine, lab-made synthetic oils that are better lubricants than hydrocracked oils as they are built for their specific use, rather than the hydrocracked oils that are modified to perform a purpose.

Ester based oils are the top end of oil technology and give the best protection available. The ester content (usually ester oils are mixed with PAO oils) has several functions that are very useful. Esters are electrostatically charged so they stick to metal surfaces, meaning that when the vehicle is started, there is already a layer of oil present. They are also more stable at higher temperatures, making them ideal as performance lubricants. The ester content also helps to make those oils better lubricants in general.

Is it okay to mix oils?

Generally speaking, yes! Mixing oil brands, types (synthetic, semi-synthetic and mineral) and viscosities is fine. There are a few exceptions;castor and plant based (as used in some biodegradable oils) are not safe to mix with conventional oils. The only problem with mixing oils is that the quality of the better oil is diluted by the lesser one.

Do I need a diesel or petrol oil for my car?

In the case of cars with diesel particulate filters (DPFs/FAPs), they will often need an oil that meets an ACEA C specification, which relates to low ash oils. The ACEA specification of an oil is always written on the bottle (so long as it meets the spec!) The use of oils that do not meet the correct ACEA C specification can result in the particulate filter becoming blocked, an expensive repair.

Other than that, there isn't really such a thing as a diesel engine oil as the vast majority of oils are suitable for both petrol and diesel engines, regardless of how they are marketed. If you look at the specifications listed on an oil, there is usually an ACEA A and an ACEA B specification. The A refers to petrol engine specifications and B to diesel. You will see that the numbers next to the letters are either the same or very close, meaning that the oil is suitable for both types of engine.

Many car manufacturers have their own specifications and as long as the oil meets the relevant one, there is no need to consider the ACEA specifications as they will be part of the manufacturer ones.

How often should I change my oil?

The life of the oil is dependent on many factors.

Full synthetic oils last longer than semi-synthetics or mineral oils, so although they may cost more in the first place, a full synthetic can work out as a cheaper option in the long run. Many cars specify the use of full synthetic long-life oils and these may last over 20000 miles or up to 24 months.

If the car is used on track, the oil is subjected to far harsher conditions than motorway use. That may mean that a good track oil will have broken down sufficiently to need changing after 10 hours of use, whereas the same oil would be good for over 100 hours of use on motorways. Short journeys are very hard on the oil as it does not get the chance to get warm and flow properly as well as acceleration and deceleration making the engine work harder. Motorway use is the easiest condition for oil, the speeds are fairly consistent and rarely push the engine hard, there is plenty of air flow to help cool the engine and the oil has a chance to get up to temperature and flow properly.

Certain engines suffer from fuel dilution (fuel mixing with the oil) and that is one of the quickest ways that an oil can breakdown.

Should I use an oil additive?

Generally, no. Good quality engine oils already contain a complex additive pack including detergents and dispersants, anti-wear, anti-corrosion and anti-foaming additives. The only additives we sometimes advise using are the limited slip differential friction modifiers, for certain differentials, and engine oil additives to assist in the process of breaking in a new engine.

My engine burns oil - should I use a thicker one?

It depends on the engine, what sort of use it gets, how much oil is being used and type of oil being used.

Certain engines really prefer a specific grade of oil to operate optimally, others aren't so fussy. It's best to ask us if you aren't sure if your car can use a range of different viscosity oils.

Most car manufacturers consider it acceptable for an engine to burn a litre of oil every 1000 miles or in some cases, 1000km. While topping up the oil at that frequency may be annoying and possibly expensive, there is generally nothing to worry about.

Using a full synthetic oil may help to reduce oil consumption if a mineral or semi-synthetic oil is being used. Mineral based oils consist of a mix of different sized molecules and the smaller ones can evaporate and then burn relatively easily, increasing the rate of oil consumption. The molecules in synthetic oils are uniform, so they are less likely to evaporate and burn.

My car is only being used on the road - do I need a full synthetic oil?

It depends on the car. Certain manufacturers specify that oils must be synthetic to meet the warranty requirements, so by using a more basic oil, your warranty can be invalidated

If your car has a diesel particulate filter, all the oils that meet the ACEA C specifications are synthetic and by not using one of those, the filter will become blocked.

If a car requires a 0w-x grade of oil, then it must be a genuine synthetic oil as it is impossible to make an 0w viscosity oil from mineral oils.

Even in cars that do not need oil that meet the above criteria, most of the time a synthetic oil is a preferable option as they give better protection and last longer. This is very relevant in engines used on track.

Will using a certain oil help my engine to make more power?

When a top quality oil of the correct viscosity is used, a vehicle may actually have a higher power output at the wheels than with other oils. The 'gain' in power is actually a reduction of the power lost in the engine. Internal resistance due to pumping losses and viscous drag and friction is where power is lost and minimising those will lead to more efficient running. Using a good oil reduces the friction as well as increases the protection.

A common approach to lubricating a powerful engine is to use as thick an oil as is available, but that adds to the internal resistance as the engine has to work harder to move the oil. That can also lead to increased wear in the engine as the oil does not flow as well as the engine would like. Often an increase in the quality of the oil used rather than the viscosity will be sufficient for many modified cars and that will actually give better protection as well as a slightly increased power output.

What colour is oil?

Automotive oils are naturally clear, not the amber colour that people assume they are. The reason they are often amber coloured is due to a dye manufacturers add and is only added as people assume oils should be a certain colour.

There are many oils on the market that differ from the 'norm' and this is simply due to the addition of different coloured dyes. The dyes have no actual benefit to the oil, other than making it stand out as different to the rest.

Why does my oil turn black?

As well as lubricating an engine, another important feature of oil is that it cleans, removing combustion by-products from the engine and keeping them in suspension in the oil. This prevents the by-products from settling and building up as deposits in the engine.

Should I use an oil flush?

In the vast majority of cases, there is no need to flush the engine and flushing can be harmful. What can happen is the flush can loosen harmless deposits in the engine, but then not remove them. Your new oil goes in and after it gets warm and is flowing nicely, the bits which are loosened come off into the oil, so you end up with hard bits floating around in your oil - the last thing you want! If you really want to flush the oil system, the best thing you can do is drain out the oil that is in there, put in some basic mineral oil and run the car for a short while so the oil gets nice and warm. After running it, drain out the mineral oil and put in the correct oil.

What oil should I use to run in an engine?

A basic mineral oil should be used for running in as friction between the piston rings and cylinder linings is needed to allow the engine to bed in properly. If a synthetic oil is used, it prevents sufficient friction being generated and can lead to the bores becoming glazed. That causes a loss of power and increased oil consumption. We also sell specialist running in oil and trouble-shooting products to assist with running-in.

My garage recommends a brand of oil in my car, you recommend something different

So is our recommendation safe to use? Yes, absolutely. Garages often only stock one brand of oil, so they suggest that you should use that, but as we stock several brands, we often have something from a different manufacturer that will be as good if not better than the oil the garage uses.



If you have any other questions, please:

About Us | Contact Us | Returns | Oil Guide | Delivery | Payment | FAQ | Feedback

Additional site navigation