The K&N 33-2703 is a panel-style replacement engine air filter built on oiled cotton gauze media. It is pre-oiled and sized to drop into the factory airbox of select Mercedes-Benz models, so it replaces the stock paper element without modifying the intake. The manufacturer describes it as a high-flow filter that keeps filtration levels high, and it rates efficiency at up to 99%. Its main advantage over a stock element is that it is washable and reusable. You clean it, re-oil it, and reinstall it instead of buying a new filter each service interval, which offsets the higher upfront price over time.
Fitment is the first thing to verify. The manufacturer lists this filter for the 1998-2003 ML320, 1996-2000 C230, 1993-2001 C280, and 1997-2003 CLK320. Application lists from other sellers differ on model years and sub-models, so confirm your exact year, body style, and engine before ordering. Searches for a 98-03 ML320 drop-in filter, a 96-00 C230 washable air filter, or a reusable CLK320 intake filter will bring up this part, but only the manufacturer's application guide should settle compatibility. Compared with an OEM paper element, which mainly traps particles, the oiled cotton media is meant to capture dirt while allowing more airflow.
Installation is a straightforward swap. The manufacturer's instructions describe removing the disposable factory filter and seating the K&N in its place, and the filter ships pre-oiled. Before reinstalling, check that the airbox lid and clips seal fully so unfiltered air cannot bypass the element. For cleaning, the manufacturer specifies re-oiling with about 1.64 oz (48 ml) of K&N filter oil after washing. Keep the oil application light, since too much oil can cause dirt to cling to the media. Keep the instruction sheet with your maintenance records.
The manufacturer lists the ML320 (1998-2003), C230 (1996-2000), C280 (1993-2001), and CLK320 (1997-2003). Fitment data from other sources varies, so confirm your year, model, and engine against the manufacturer's application guide before buying.
No. The manufacturer states the filter is pre-oiled and ready to drop into the factory airbox. Oil it again only when you clean it, using the manufacturer's listed quantity of about 1.64 oz (48 ml).
No. The manufacturer designs this filter to fit the stock airbox, so the factory housing is used as-is.
This is a beginner-level job that usually needs no special tools. Open the airbox, remove the disposable factory element, and drop the K&N in with the same orientation. Make sure the airbox lid seals fully and the clips close evenly so no unfiltered air bypasses the element. Check the filter after the first few hundred miles for proper seating. Clean and re-oil it at the intervals described in the manufacturer's instruction sheet.
