Thread: Oil Change tip

Hi All,

Tip for the day.

I have heard lately some mechanics aren't prefilling the oil filter before putting the new one on.

You should take your new oil filter and prefill it up to about 2/3-3/4 full before you screw it on. A dry empty fillter just helps air get into your system. Not good for a Rotax. Then the engine should be hand proped for 20 times to make sure oil has filled the filter and any air is expelled. Make sure your mechanic knows he should prefill the oil filter.

p.s.
Prefilling the oil filter should be done on most any engine.

Roger,
It really is amazing how many people arent aware of this procedure even though the purpose and benefits are very obvious. Thanks for pointing it out because it is very critical.

Hi pre-filling the filter is the right/best thing to do but you have to be pretty quik screwing it on as most of the oil will pour out as it does when you unscrew them ..

Im booked on a 2 rotax maintenance course's this November it will be good to get some more inside info on repair's etc from the experts even though i have been repairing and servicing mine for over 14 years 2 and 4 strokes so must be doing something right .We dont have the same maintenance restrictions that you have in the USA we can do our own including complete rebuilds i would point out that i have and been a vehicle mechanic for over 30 years and still am so not a complete novice ..

Rgs Mike

I agree with the concept of filling the filter before it goes on. I do it on every change I have ever done provided I can keep the oil in the filter. This is easy on most cars and light trucks. However, in the case of the 912, I agree with Mike. Not only can't you do this without making a mess, the Rotax written and video instructions make no mention of it.

So, I don't put oil in the filter. I do rotate the prop 20 times as called for then I motor the starter without starting the engine. That produces oil pressure on the gage. Then I start the engine. You can easily motor the starter without getting it to fire if you do it on a cold engine with the choke off.

If some one can explain to me how to put a full filter on the 912 without making a mess, I'll gladly do it.

Now, undoubtedly, someone out there has a simple non messy way of doing this and I'm going to feel realy stupid for not thinking of it. But, that's life!!

For oil changes I have a piece of corigated plastic that I use for a chute under the filter for removal of the old filter and installation of the new filled oil filter. If you are careful and quick you don't lose that much of the new oil, but the oil that you do lose runs down the chute into you bucket with little mess.

I also use a chute. Maybe I need a better one instead of just a piece of bent cardboard.

This is very important because when you don't do this air gets into the system and then it could affect your hydraulic valves (not air valves). This can cause real headaches. It can cause dry areas on push rod ends. Your fliter when about 2/3 - 3/4 full can only flow out of the threaded opening because the other holes have a anti drain back silicone cover. If you hold a rag under the filter and resonably quickly tip it up and give it about a half turn on the threads it should not be pouring out of the other holes. Then just screw it on in a timely fashion. I can't believe you guys would worry about a little drool on a rag over causing damage to the engine. If you do it with a dry filter or open any other oil lines you really should do an oil purge. Rotating the prop 20 times won't fix a dry filter or air introduction into the system, if it did then Rotax wouldn't have an oil purge procedure. The air is in there and possibly not coming out or just sitting in a bad space. The lifters need oil to operate and the rod ends have holes for lubrication. Get air into either space and your in trouble and won't even know it until it's too late.

Pre-fill those filters and hold a rag under it. For the waste of 2/10 of an ounce it is worth it.

John,

Don't make me call Brian Carpenter. :P

This is my first post here.

I don't have a CT Design, but do have a ROTAX 912ULS2 in my 31 Sky Arrow.

In neither of the two oil changes I've been involved with have we put oil in the filter - it seems like it would make quite a mess. We did turn the engine over by hand about 30 times before starting it.

I did have a thought - how about jacking up one side of the plane (I guess the left side on a CT). It seems like if you could even get an add'l 10-20º of tilt, that might allow just a bit extra oil to stay in the filter. I'll probably try it next time and report back when I do (mine's a pusher so I'll tilt the other way!).

BTW, on BMW "K" bikes I always fill the oil filter - but its "normal" orientation makes that easy.

Take one of your empty oil bottles. Most of them are flat nowadays. Cut the top and one face out of a side leaving the bottom in tac.This little mess catcher will fit snugly under the filter before, during, and after the entire filter removal and replacement. It sits in there nice and tight without holding it.

Hi Eddie,

Welcome to the dark side. (aka CT forum). LOL
I'm the one that posted on the Sport Pilot forum about the regs.
It is always a good idea for any oil change in any motor (motorcycle, ATV, auto) tohave the oil filter pre-filled. It is not messy because you have the silicone anti drain back barrier. If you look at your filters they have the center hole and the smaller outer holes. The oil can not drain back out these holes. They are there to keep oil in the filter and not draining out when an engine is not running. I fill the center hole up just below the top and then the oil level goes down as the oil spreads out and adsorbs in the filter element. I fill it one more time and then leave it while I change the oil. The level when I come back is about 1'2 full. Yes if you fill the filter all the way to the top and leave it there then a horizontal filter will leak a tad bit until you mate up the center hole. This pre-fill practice is usually taught at most mechanic schools and a good mechanic will do this to help keep air out of the system, but more important dry starts.

This is a very active and informative forum. It's a good place to get straight answers.