How to choose an oil filter — what matters
The oil filter is one of the cheapest parts on a car and one of the closest to the engine. Three things matter when choosing: the part number, the internal valves and the manufacturer.
Updated:
What the filter does
Inside an engine, friction produces fine metal particles, combustion deposits and dust. The oil carries them along and the filter holds them back. If the filter stops working, those particles return to the bearings and cylinder walls.
That is why the filter is replaced together with the oil: putting fresh oil through an old filter saves a few thousand soums and contaminates the oil itself.
1. The part number — the main criterion
Filters are not chosen by appearance. Two filters that look identical can differ in thread, seal diameter and internal valves.
Take the number from the housing of the old filter, or ask the seller for the part number for your model. Aftermarket packaging usually lists the numbers it replaces.
2. Internal valves — invisible but important
These two valves are the first thing cheap unbranded filters leave out. You cannot see it from the outside — which is why the manufacturer name matters.
- Bypass valve — if the filter clogs or the oil is thick in the cold, it lets oil pass around the filter. Without it the engine can be left without oil in cold weather.
- Anti-drainback valve — keeps oil from draining out of the filter when the engine is off. If it fails, the first seconds of every start happen without oil pressure.
3. Manufacturer and packaging
- The box should carry the manufacturer name, a part number and a country.
- Printing on the housing should be crisp and the label applied straight.
- The rubber seal should be elastic — a hardened seal will leak.
- A new seal should come with the new filter.
Nexia, Lacetti, Matiz and other common models
For the most common models in Uzbekistan filters are easy to find and the choice is wide — which is exactly why there is so much unbranded stock. Pick the filter from the catalogue and check the "Fits" list on the product page.
Two common fitting mistakes
- Not oiling the seal. Before fitting, the rubber ring is smeared with clean oil — otherwise it folds over and leaks.
- Tightening with a wrench. A filter is tightened by hand: once the seal makes contact, turn it the specified amount further. An overtightened filter cannot be removed next time.
Frequently asked questions
- Must the filter be replaced at every oil change?
- Manufacturers generally require exactly that: the filter is replaced with the oil. The exact schedule is in your car's manual.
- How does an expensive filter differ from a cheap one?
- In the filter medium, its surface area and the quality of the internal valves. None of that is visible from outside, so the manufacturer name remains the main criterion.
- How do I check the filter fits my car?
- By the part number from the old filter or the manual. More on this: checking compatibility.