I have seen on volvo parts lists, that the proper filter is 3840525.
The filter that was on my boat when I bought it (second hand) is 3581621.
I've also seen on web searches that 3581621 is the proper filter.

The gasket size seems similar (although not exact) but the biggest difference is 3581621 is about twice as long as 3840525 is.

Which one do I use??

Peas, welcome to Sailnet. An introduction would be nice.

To answer your question: As you say, the proper oil filter for your engine is the Volvo 3840525. That is the one you should be using.

The other one is probably an aftermarket replacement for the original. An oil filter is hardly a sophisticated piece of kit, but, if it's time to replace it, I'd think you'd be crazy to use anything but the correct unit. Volvo engines are temperamental enough already..

Thanks for the quick reply.
I went back to the local Penta service centre and they advised that the 3840525 was the original spec and the 3581621 is the new spec, which is a larger capacity filter. Not sure if that is the case, of if it was just what he thought would be a reasonable response as to why my engine had a Volvo 3581621 filter on it.

In any case, I have an engine with fresh oil now and a 1 year old filter. I used the motor for maybe 40 hours...what are thoughts on if that filter will hold for another season, or if I should do another oil change in the spring, when we relaunch our boats?

Peas, that could be true, but since (a) best practice, and the Operating Manual, say to replace the filter when you replace your oil and (b) most sailboat people don't run their engines for anywhere near the 100hour factory-spec interval between changes, having a bigger filter is a waste of money. IMO.

If you have the bigger filter already, I suggest you change both in the spring - for the correct one this time.

I'm not sure when the engineers re-spec'd but the MD2030 I installed new about 10 years ago came with the 3581621. 3581621 is a Volvo part number - not aftermarket so it is the correct filter for the engine now.

I agree with Heartly18 and change the filter annually. I do the filter change at the start of the season with new oil and an oil only change prior to haulout. On the rare seasons where I do get 100 hours on the engine, I do filter and oil at that time in addition to the launch / haulout changes.

Fair Winds

Al

Part numbers for oil and fuel filters MD2030.
Oil filter is 3581621
fuel filter is 3840525
cross reference for fuel filter is Wix 33386

I will post cross reference for oil filter when I get it.
Ken

Hi.
Filterfor oil is 3581621 and fuel is 3840525
You can get cross reference here.
VOLVO FUEL AND OIL FILTER CROSS REFERENCE - Cruisers & Sailing Forums
Hope that helps.
Oil filter should be changed at least once a year and fuel filter as well. if engine makes black smoke, it is sometimes because of blockage of fuel filter.
Ken J-mech (Diesel Mech)

Is that the right way around?

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!