Tuesday, 23 August 2011 16:20

What’s in an oil filter?

Written by  Rotax Owner

Rotax has a new addition to their parts inventory: the new Rotax oil filter. It’s manufactured by Mahle, part #825-010 (012) and made in Austria. Rotax took a look at all the different engine installations and I believe they thought it was time for a change and a change for the better it was. The new oil filter comes in an all white box verses the old filter box that was blue/white.

Related Videos are: Oil Filter InstallationOil Change ProcedureOil Level Check


It is slightly longer by 3.5mm or .138 in., but this is not where the changes stop by any means. Some changes were sweeping. For instance, some are specifically designed with the mounting of the oil tank in mind. This is important because we have a dry sump system and not a wet sump system . The white silicone drain-back preventer (valve) is improved with little or no oil being allowed to drain out of the filter while the engine just sits. This was designed for engine setups where the oil tank is mounted a bit too low, which prevents the oil from draining back into the tank and out of the filter and engine.


Another change was the addition of a “one way check valve”. This feature is for those oil tanks that are mounted too high above the recommended oil tank location. It keeps oil from draining out of the tank back down into the engine.


The next change is a new bypass pressure spring. The old filter used a piece of spring steel. This new oil filter has a smooth round edge spring so it doesn’t have any sharp edges to wear through the filter housing. The old bypass pressure was 1.1 bar or 16 psi. This new filter is 1.2 bar or 18 psi. This will stop some filters from opening for a second or two at start up. The old oil filter could be pre-filled with oil which made it easy, but with this filter you can’t pre-fill with oil and you must turn the prop to put oil into the filter before your first start after an oil change.



So you see Rotax has made some fairly big changes to the inside of the oil filter to better help its users deal with their different engine applications. I have attached several pictures so you may see what is actually on the inside. I swore I wouldn’t cut open a perfectly good filter and wait for a used one, but curiosity got the better of me. For the photography critics out there, no I didn’t quit my day job.

I hope this helps you to understand the new Rotax oil filter.

Related Videos are: Oil Filter InstallationOil Change ProcedureOil Level Check

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0 #9 oil pressure after filter changeenergy@whitsunday.net.au 2011-10-27 15:17
The hose clamp around the base is the way I have kept my filter secure for the last 7 years. It is simple and effective
Are our oils not clever enough to withstand a few revolutions, after an oil change, until pressure builds up? Many oils claim to protect an engine for some time, after oil pressure failure.
-1 #8 oil filter safetyskipd 2011-09-27 15:18
Leonard- I am not sure that you can do that without an LOA from ROTAX- what do you think? I like the idea as well.
-1 #7 SportCruiser / PiperSportFOX Aerosport 2011-08-30 22:07
The new filter fits the SportCruiser / PiperSport 912ULS without difficulty.
-2 #6 dick Merrilldickmerrill 2011-08-27 07:18
If the new filter is any longer that the old one it will not fit the Sportcruzer(Pip er Sport). The old filter barely fits between the engine and the radiator hose.
+2 #5 New oil filter diametertrevoryoung 2011-08-27 06:51
Is the outer diameter of the new oil filter identical to the old one? The gap between the oil filter and the radiator, on my installation (912ULS), is very narrow (any increase in diameter would make it very hard to remove without damaging the rad).
0 #4 Pre fill oil filterN137SW 2011-08-27 03:37
Slowly fill your oil filter to the brim several times. Put it in the freezer for two hours. Install it (the oil won't spill because it is too thick). Let warm two hours before engine start. Now you have quick oil pressure immediately after an oil change.
+2 #3 oil filter safety236sc 2011-08-26 20:01
I installed an aviation type hose clamp around the base of the filter and safety wired thru the end slot to the head of the plug for the timing bolt. Three people I know thought this was a good idea and have done the same.
+1 #2 safety wireskipd 2011-08-26 14:03
I was really hoping that they would incorporate a way to safety wire the filter in place. I have seen two come loose after the proper "torque" has been made.
+1 #1 garbagemangarbageman 2011-08-25 16:40
You can pre fill the new filter with some oil, but I'm not sure it's worth the effort. Place a small 1/4 inch magnet on the new valve and carefully lift it a bit. Then pour oil in the filter.