Guides & help.
Choose oil and filters, plan a fluid change, and find the right products for your equipment.
Maintenance & oil selection
- How often should you change synthetic oil?
Set a synthetic oil change interval using your maintenance schedule, driving conditions, oil-life monitor, and the limits of your oil and filter.
- Full synthetic oil change: oil, filter, and preparation guide
Prepare for a full synthetic oil change with the right specification, fill quantity, filter, supplies, and a plan for recycling the used oil.
- Synthetic oil change cost: DIY vs. shop service
Compare a dated U.S. shop price with a DIY oil budget, including filters, labor, shipping, tools, and disposal. See what each example includes.
- Choosing an oil filter for synthetic oil
Choose an oil filter by vehicle fitment, construction requirements, and service interval, then compare compatible products in the filter catalog.
- Transmission fluid changes: selection, methods, and cost factors
Identify the correct transmission fluid, compare drain-and-fill and exchange services, and understand the parts and labor in a service quote.
- Differential fluid changes: front, rear, and limited-slip
Identify axle specifications, choose gear oil, check limited-slip additive requirements, and prepare a differential fluid service shopping list.
- Transfer case fluid change guide
Identify your transfer case, distinguish its fluid from axle and transmission oil, and prepare the correct parts and service information.
- High-mileage oil changes: choosing the right oil
Decide whether a high-mileage motor oil fits your engine, while keeping the correct viscosity, specifications, filter, and maintenance interval.
- Diesel oil change: specifications, capacity, and filters
Plan a diesel oil change using the engine specification, emissions requirements, service-fill capacity, correct filters, and actual duty cycle.
- Harley-Davidson oil change: oils, filters, and kits
Match your Harley-Davidson model and engine to the correct oil, filter, and kit, and check whether primary and transmission service need separate supplies.
- Understanding oil viscosity: what 5W-30 means
What the numbers in a grade like 5W-30 or 0W-20 describe, what they do not, and how to choose a viscosity your engine allows.
- Full synthetic vs. synthetic blend vs. conventional oil
Compare full synthetic, synthetic blend, and conventional motor oil by application, specifications, cost, and service requirements.
- Synthetic oil myths and facts
Common claims about synthetic oil, including leaks, switching back, break-in, and mixing, compared with how lubricants actually work.
- Winter and summer vehicle maintenance
A seasonal checklist for oil, fluids, and storage, plus how cold starts, heat, towing, and short trips affect maintenance.
- Used oil recycling and waste reduction
How oil choice and service intervals affect waste, and how to store and recycle used motor oil and filters properly.
- Lubricants beyond the engine
Transmission fluid, gear oil, grease, brake fluid, and coolant: what each system needs and why the wrong fluid causes problems.
- Oil for performance and racing engines
How lubricant needs change for turbocharged, modified, track, and competition engines, and when racing oil is and is not appropriate.
Shopping & account help
- AMSOIL 5W-30 motor oil
- AMSOIL 10W-40 motor oil
- AMSOIL engine oils
- AMSOIL transmission fluids
- AMSOIL automatic transmission fluids
- AMSOIL manual transmission fluids
- AMSOIL powersports transmission fluids
- AMSOIL promo codes & current offers
- AMSOIL Preferred Customer benefits & membership
- AMSOIL account login
- Create an AMSOIL account
- AMSOIL customer service
- What oil does my car need? Find the right AMSOIL product
- Request an AMSOIL catalog
- AMSOIL commercial product information
- AMSOIL installer product information
- About AMSOIL and your independent dealer
- AMSOIL warranty information
- AMSOIL performance testing
- Reading AMSOIL customer reviews