126 Products
CASTROL
Castrol's represented range is led by engine oil, with EDGE, MAGNATEC, GTX and other formulations across viscosities such as 0W-20, 0W-30, 5W-30, 5W-40, 10W-40 and 10W-60. It also includes POWER1 motorcycle oils, TRANSMAX manual, automatic and axle fluids, DOT 4 brake fluids, coolant, chain products and a small number of specialist lubricants. Similar pack size or viscosity does not make these fluids interchangeable.
Begin with the vehicle or equipment handbook. For engine oil, record the required SAE viscosity and the complete performance specification or manufacturer approval, then compare both with the exact Castrol product label and current data sheet. A 5W-30 meeting ACEA C2 is not automatically an alternative to a 5W-30 requiring C3, a named vehicle-maker standard or another performance category. Engine design, emissions equipment, fuel type and service regime can all affect the requirement.
Transmission choice is even more application-specific. Establish whether the unit is a conventional automatic, CVT, dual-clutch transmission, manual gearbox, transfer case or final drive, and use the exact fluid standard. Do not select automatic transmission fluid by colour or assume a broad multivehicle description covers every unit. Brake fluid must match the required chemistry and DOT or other specification; Castrol expressly warns that its glycol-based DOT 4 products are unsuitable where mineral-oil fluid is specified.
Check level on level ground and by the manufacturer's temperature and engine-running conditions. Clean around caps before opening, use dedicated filling equipment and avoid mixing unknown fluids. After servicing, inspect the filter, drain plug, seals, hoses and disturbed joints, then confirm level again and investigate any warning or leak. Used engine oil can harm skin and the environment: wear suitable gloves, wash contamination promptly and transfer drained fluid in a secure labelled container to an authorised collection route. Never pour oil, coolant or brake fluid into drains or onto the ground.
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Castrol oils and fluids for different vehicle systems
The 140 Castrol products represented here are predominantly lubricants and service fluids. Engine oil accounts for about one hundred items, including EDGE, MAGNATEC and GTX families in passenger-car and commercial pack sizes. Motorcycle oils, TRANSMAX gearbox and automatic-transmission products, axle lubricants, DOT 4 brake fluid, coolant, chain spray and other maintenance products broaden the selection.
Fluid selection is a specification exercise. Brand family, viscosity and pack volume help narrow the result, but the exact application standard is decisive. Castrol's own UK guidance directs users to the vehicle handbook for the required industry specification, type and grade, and provides a product finder as another reference.
Read the full requirement
| Fluid group | Primary selection data | Secondary checks | Unsafe shortcut |
|---|---|---|---|
| Engine oil | SAE viscosity plus ACEA, vehicle-maker or other required specification | Engine, fuel, emissions system, service interval and operating conditions | Choosing any bottle with the same viscosity |
| Motorcycle engine oil | Viscosity and motorcycle/engine requirement | Wet clutch, gearbox sharing, two- or four-stroke design and maker standard | Substituting passenger-car oil without approval from the handbook |
| Automatic transmission fluid | Exact transmission-fluid specification | Unit type, model, build date, fill procedure and service temperature | Selecting by red colour or the letters ATF alone |
| Manual and axle oil | Required viscosity and GL or manufacturer standard | Synchromesh materials, limited-slip needs and separate final-drive fill | Assuming GL-4 and GL-5 are interchangeable in every gearbox |
| Brake fluid | Required chemistry and DOT/ISO or vehicle specification | Service interval, moisture condition and correct bleeding process | Mixing glycol fluid into a mineral-oil system |
| Coolant | Vehicle coolant standard and concentrate/premix status | Dilution water, system materials, climate and existing fluid | Choosing by colour, which is not a universal specification |
Engine-oil viscosity and specification
An SAE multigrade such as 5W-30 describes viscosity behaviour at defined cold and hot conditions; it does not state all of the oil's wear, deposit, catalyst, particulate-filter or fuel-economy performance. The first number with W concerns low-temperature behaviour, while the second relates to viscosity at operating-temperature test conditions. It is not a direct measure of ambient temperature or oil quality.
Next read the performance category. The represented products carry a variety of ACEA categories and named manufacturer standards. Castrol's official MAGNATEC page demonstrates the differences within one family: 0W-20, 0W-30, 5W-30 and 5W-40 products are listed with different ACEA, vehicle-maker and other specifications. Therefore, family name plus viscosity still does not finish the match.
| Label element | What it tells you | How to use it |
|---|---|---|
| SAE grade | Defined low- and high-temperature viscosity performance | Match the grade permitted for the engine and operating conditions |
| ACEA category | A European engine-oil performance framework | Require the category and sequence stated by the vehicle maker |
| Manufacturer approval | The product is presented as approved to a named maker standard | Match the full code, including suffixes and revisions where relevant |
| Meets or suitable-for wording | A stated suitability claim that may differ from formal approval language | Read the current data sheet and the vehicle requirement carefully |
| Product family and suffix | Distinguishes formulations within EDGE, MAGNATEC, GTX or another line | Do not omit letters such as C2, C3, LL, D or A3/B4 |
| Pack volume | The quantity supplied | Compare with service fill plus an allowance only where needed for level setting |
EDGE, MAGNATEC, GTX and other engine oils
Product-family positioning does not override the handbook. EDGE appears in this range across several grades and specifications, as does MAGNATEC. GTX includes formulations for different applications, while specialist and commercial products address still other duties. Choose the exact named variant whose current label and data sheet satisfy the required standard.
Do not infer that every product carrying terms such as synthetic, part synthetic or synthetic technology has the same base-oil composition or application. Castrol's UK technical FAQ specifically says certain GTX and MAGNATEC grades labelled with synthetic-technology wording remain part synthetic. For selection, the documented specification and approval are more useful than a broad formulation descriptor.
Top-up oil should also meet the vehicle requirement. If the existing fill is unknown, a small emergency addition may call for handbook advice, followed by correction at the earliest suitable opportunity. Repeated topping up suggests consumption or leakage that needs investigation rather than a larger container.
Oil-change preparation and level setting
Confirm fill quantity, filter, drain-plug procedure, sealing washer and torque before draining. Warm the oil only as the service method requires; hot lubricant and exhaust parts can burn. Support the vehicle on approved points if access underneath is necessary and never rely on a jack alone.
Clean the filler area, use a drain container with adequate capacity and keep dirt from open ports. Replace seals specified as single-use and tighten with the prescribed method. Over-tightening can damage a sump or housing, while under-tightening can cause loss. Refill in stages, allow oil to settle or circulate as instructed, and read the dipstick or electronic level under the stated conditions.
Overfilling is not protective. It can cause aeration, crankcase issues or after-treatment trouble depending on design. After starting, confirm pressure indication, inspect the filter and plug, stop the engine and recheck the final level at the required interval.
TRANSMAX automatic, manual and axle fluids
Castrol separates automatic, CVT, manual and axle fluids because their friction and material requirements differ. The official automatic-fluid page lists TRANSMAX ATF DX III Multivehicle for specific older Dexron or Mercon applications, while a separate TRANSMAX CVT product has its own list and exclusions. Neither description supports use in every automatic transmission.
Manual transmission oils also differ. Castrol lists Manual FE 75W, Manual Multivehicle 75W-90, Manual Transaxle 75W-90 and Manual EP 80W-90 with different performance claims and standards. A limited-slip differential can require specific friction behaviour not provided by an ordinary axle oil.
| Before opening a transmission | Reason | Verification |
|---|---|---|
| Identify the exact unit | One vehicle can use different transmissions by engine, date or market | Unit code, vehicle data and manufacturer service information |
| Confirm fluid standard | Viscosity alone does not define friction and material compatibility | Handbook/service data against the exact Castrol data sheet |
| Find the level method | Some units use a temperature-dependent overflow procedure | Specified temperature, engine state, gear sequence and level plug |
| Locate drain and fill plugs | Opening the wrong plug can affect adjustment or leave the unit unfillable | Diagram and physical identification before draining |
| Use clean dedicated equipment | Cross-contamination changes fluid performance | Labelled pumps, sealed containers and cleaned adaptors |
Brake fluid and coolant
Castrol lists Brake Fluid DOT 4 and React Performance DOT 4 with FMVSS 116 DOT 4, ISO 4925 Class 4 and other stated standards. Both official entries warn against use where mineral-oil-based brake fluid is recommended. Check the reservoir cap and vehicle data; never decide from fluid colour.
Brake fluid absorbs moisture during service, lowering boiling performance. Castrol recommends checking it at every service and refers users to vehicle-maker change guidance. Opening a hydraulic brake system introduces safety-critical bleeding and contamination risks. Use fluid from a clean, recently opened container as directed, protect paintwork and verify a firm pedal and leak-free system before movement.
Coolant choice depends on its chemistry and vehicle standard. Castrol's Radicool entries list individual standards and distinguish products, while its guidance emphasises correct dilution. Do not mix coolants merely because their colours look similar. For concentrate, use the water quality and ratio specified; premix should not normally be diluted unless its instructions say so.
Motorcycle oil, chain care and specialist lubricants
Motorcycle engines may share lubricant with the gearbox and wet clutch, so friction requirements can differ from passenger-car use. Match POWER1 or another Castrol motorcycle product to the bike handbook, engine type, viscosity and performance standard. Do not put four-stroke oil into a two-stroke oiling system or reverse the substitution.
Clean and lubricate a drive chain by the motorcycle procedure, keeping product away from brake discs, pads and tyre tread. Inspect slack, tight spots, sprocket wear and damaged seals rather than using spray to conceal mechanical wear. Hydraulic and other specialist oils likewise require equipment-specific viscosity and specification.
Handling, disposal and MOT context
HSE warns that frequent and prolonged skin contact with used engine oil can cause dermatitis and other serious skin disorders. Wear suitable gloves, avoid oil-soaked clothing, wash with appropriate skin cleanser and never use solvents on skin. Consult the product safety data for new fluids and deal with spills promptly.
Keep waste streams separate in sealed, labelled containers. GOV.UK includes oils among household waste that must be disposed of correctly; local councils provide the relevant route, and commercial workshops have additional waste duties. Brake fluid, coolant and contaminated absorbents may need different handling from used oil.
DVSA's MOT manual includes fluid-leak and brake-fluid-level checks. A leak judged likely to harm the environment or create a safety issue can be a defect according to its severity and location. Cleanliness after servicing is useful for inspection, but do not wash away evidence without correcting the source.
Common Castrol fluid-selection mistakes
- Matching only the SAE grade and overlooking ACEA or vehicle-maker requirements.
- Dropping important suffixes from a Castrol product name when comparing variants.
- Choosing transmission fluid by colour or a general ATF description.
- Assuming a higher GL or DOT number is automatically suitable as an upgrade.
- Mixing coolant colours without confirming chemistry and vehicle standard.
- Checking a temperature-sensitive transmission level under the wrong conditions.
- Overfilling an engine or gearbox instead of following the defined level method.
- Combining used oil, coolant and brake fluid in one disposal container.
Castrol questions and answers
Q: What Castrol products are most common here?
A: Passenger-car engine oils lead the range, followed by motorcycle, transmission, brake, coolant and maintenance fluids.
Q: Is any Castrol 5W-30 suitable for a 5W-30 requirement?
A: No. The exact ACEA, manufacturer and other performance specifications must also meet the vehicle requirement.
Q: What does the W in an oil grade mean?
A: It identifies the winter-side viscosity classification within the SAE multigrade, not a quality ranking.
Q: Are EDGE and MAGNATEC interchangeable?
A: Product family alone cannot decide; compare the complete grade, specification and approval for the application.
Q: Can I use ATF in every automatic gearbox?
A: No. Conventional automatics, CVTs and dual-clutch units can require fundamentally different specified fluids.
Q: Is GL-5 always better than GL-4?
A: It is not a universal upgrade; gearbox and synchroniser compatibility depend on the documented unit requirement.
Q: May DOT 4 be used in a mineral-oil brake system?
A: No. Castrol specifically excludes its listed glycol-based DOT 4 fluids from systems requiring mineral oil.
Q: Can coolant be selected by colour?
A: Colour is not a universal chemistry code; use the vehicle standard and exact product data.
Q: Should engine oil be checked hot or cold?
A: Follow the vehicle's defined temperature, level-ground and waiting-time conditions because methods differ.
Q: What if the oil level keeps falling?
A: Check for leaks and abnormal consumption rather than treating repeated top-ups as routine maintenance.
Q: Can used engine oil go in household rubbish?
A: Use the authorised local collection route and a secure container; never pour it into drains or soil.
Q: Does fresh fluid guarantee an MOT pass?
A: No. Level, leakage, system operation and other testable conditions still need to meet the inspection requirements.