Filters
Filters keep dirt out of the engine, the cabin, and the fuel and transmission systems. Retail catalogs group them together because they are serviced on a schedule, often at the same visit.
Common parts
- FL·1Engine oil filters, spin-on and cartridge
- FL·2Engine air filters
- FL·3Cabin air filters, standard and carbon
- FL·4Fuel filters, in-line and in-tank
- FL·5Automatic transmission filters and pan kits
- FL·6PCV valves and breather filters
- FL·7Diesel fuel and water separator filters
Signs of trouble
A dirty cabin filter shows up as weak airflow from the vents, a musty smell, or windows that fog easily. A blocked engine air filter can reduce power slightly and is easy to see when you hold it to the light. A clogged fuel filter can cause hesitation under load or a hard start. Most filters do not give a warning at all, which is why the service schedule is the better guide.
Finding the right fit
Filters that look alike can have different thread sizes, gasket diameters, bypass valve settings, and anti-drain-back valves. Match the filter to the engine, not only the model. Cabin filters sometimes changed size mid-generation, so compare the dimensions on the old one. Some vehicles do not have a serviceable fuel filter at all, because it is built into the in-tank module.
Oil, fluids, and chemicals
This family covers the fluids that lubricate, cool, and transmit force, plus the cleaners, sealants, and additives sold beside them. Many of them carry a specification code that matters more than the brand.
Common parts
| Ref | Part group |
|---|---|
| FL-01 | Motor oil by viscosity and specification, such as an API, ILSAC, or maker approval |
| FL-02 | Engine coolant and antifreeze by chemistry type |
| FL-03 | Automatic transmission fluid, CVT fluid, and manual gear oil |
| FL-04 | Brake fluid by DOT rating |
| FL-05 | Power steering fluid |
| FL-06 | Differential and transfer case fluids |
| FL-07 | Windshield washer fluid |
| FL-08 | Greases, thread lockers, sealants, adhesives, and cleaners |
| FL-09 | Fuel and oil additives, and A/C refrigerant |
Finding the right fit
Read the specification, not just the viscosity. Many engines need an oil that meets a particular maker approval, and the code is printed in the owner’s manual or on the oil fill cap. Coolants use different chemistries, and some do not mix well. Transmissions are especially specific: a fluid labeled as multi-vehicle may not meet a particular maker’s requirement, and a CVT normally needs its own fluid. Brake fluid ratings are not all interchangeable, so use the one printed on the reservoir cap.
Fitment checklist
- The specification printed on the oil fill cap or in the owner’s manual
- The coolant type named on the reservoir or in the manual
- The transmission fluid name the maker calls for, not just ‘multi-vehicle’
- The DOT rating printed on the brake fluid cap
- Filter thread size, gasket diameter, and bypass valve for the exact engine
- Cabin filter dimensions compared with the old filter
Before you order
Start with the year, make, model, and engine, then narrow it down with the trim, drive type, and any option the part depends on. The VIN is the most reliable way to do that, because many parts catalogs and dealer counters decode it to the exact build. If the old part is in hand, its original-equipment number is the best cross-reference. Aftermarket brands publish their own numbers and usually list the original number they replace. Two listings that both say they fit can still differ, so compare the photos, connectors, mounting points, and the notes in the listing. The find the right part guide covers this step, and the all makes reference lists each maker’s official parts catalog.
Once you know the part number, compare the same number across stores. Look past the first price at the core charge, shipping, the return window, and what the warranty covers and who honors it. A remanufactured part, a new aftermarket part, and an original-equipment part can each be the right choice, but they are not the same purchase. The compare prices and warranties guide walks through what to read. Prices on PartIndex carry the date they were recorded, so confirm the current price and fitment with the retailer before you buy.
Used oil, coolant, and other fluids are toxic. Coolant tastes sweet to pets and children, so clean up spills right away. Take used fluids and filters to a recycling point, which many parts stores accept. Never open a hot radiator or reservoir cap.