Join Date: Nov 2016
Location: Brittany & Corsica
Thanked 0 Times in 0 Posts
Rep Power: 0
Re: MD2030 Which Volvo Filter? 3581621 or 3840525
Unlike many I believe in continuing old threads if there's something to add as lots of us use forums for research/information.......
3581621 and 3840525 are BOTH VOLVO OIL filters. I have them both in front of me and have used both successfully (a season at a time) on my D2-55B (so that's a 2004, non-turbo'd 4 cyl 2+litre engine which does about 50hours a year). The reason I specify size, 'non-turbo' and hours is because that means it's overall a fairly unstressed, cool-running unit which will not be too fussy about oil type or filter efficiency. A turbo'd engine generates more heat/stress on components. However at 10.5 litres capacity it is as much an oil-cooled engine as a water-cooled one (no helping blast of air explains why most marine engines have higher oil capacities than car engines....)
Limiting the discussion to screw-on canister filters the major differences (apart from physical considerations such as seal dia (which IS the same on these two), screw and space issues) are the filtration media used (cleaning ability) and the capacity (flow oil fast enough and not clog up with particles quickly). Which also means, if the physical connection fits/seals, then in an emergency any filter is usable.....
- So the media inside differs to meet usage conditions - harsh or normal; tropical, temperate or cold (climate & oil viscosity affect filter flow) - and relates to particle sizes and oil flow
- The filter capacity is VERY loosely related to the engine's oil capacity (more or less oil to clean, therefore particles to hold without reducing flow). But a coarser media will require less physical space to flow enough oil. Is this then the difference between 3581621 and 3840525?
One manufacturer of vehicle filters, MANN, uses a great product numbering system to show variants of the same filter (eg WK854/3 and WK854/5) which tells you what kind of media is being used. Whenever I have the choice I opt for the 3581621 as its bigger capacity seems more suited to the engine's large oil capacity (more oil to be flowed/filtered), but I don't worry if I have to fit 3840525.
I would really like to hear a Volvo R&D engineer's explanation of the two!