Time for Oil Change

[TonyW]

Hi,

Sorry if this sounds a stupid question but when do you need to change the oil?
I thought I read in the manual a long time ago that it is after 25 hours but yesterday when I read through the manual again (and searched the pdf also) I couldn't find this. Although I've flown a lot more than 25 hours in the Comanche this is the first time I've reached 25 hours after a full "reset as new".

Regards,

Tony

[Oracle427]

For engines with oil flters

25 hours is good if you don't fly frequently, but if you're putting in several hours of flying every week, you can go out to 50 hours. Regular flying is key. Time is also a factor as sitting unused will result in corrossion. Changing the oil is necessary to avoid having the acids in the oil from combustion by products start to eat away at the engine.

For engines without oil filters 25 hours is a normal change interval.

I believe the rule for time is three months? According to the below link it is around 4 months.

And I just found this link:

https://generalaviationnews.com/2004/12 ... e-changed/

[TonyW]

Thanks Oracle,

That was helpful.

Tony

[alan CXA651]

Hi.
If i dont fly a particular aircraft for say a month , then before starting or doing a walk around , i change oil and plugs as a precaution , and on every flight prior to starting i check the hangar for any issues , and on walk around if i see the oil on the dipstick getting too dark , i will go back in the hangar and change it , just to be safe , and i flew the A2A C172 around the world east to west north to south , all on one engine with very few issues.
regards alan.

[dscott3984]

Is there a way to see current time in service on the oil? I fly with a used aircraft so it’s not a simple 25 hours on tach is time to change thing.

[Oracle427]

It would be 25 hours from the last tach time when you changed it. If you just started with a used aircraft and are in doubt about the age of the oil, then change it. It doesn't cost us anything in simulation land.

[AKar]

Lycoming SB 480F for reference.

-Esa

[dscott3984]

It would be 25 hours from the last tach time when you changed it. If you just started with a used aircraft and are in doubt about the age of the oil, then change it. It doesn't cost us anything in simulation land.

That’s kind of what I figured it would be. Time to open up a virtual logbook as all of my A2As are set up as used aircraft so I have no clue how much time I’ve put on my current oil.

[Oracle427]

Run the oil a little past 25 or 50 until you reach an even number. Then change it at the even number such as 0, 25, 50 or 75. There is no regulation requiring you to change it at the exact interval.

[AKar]

Though it would be very rare to find an airplane that has its maintenance schedule matching even figures. It gets all scrambled pretty quick. That's one thing the logbooks are for anyway. In real life, it makes sense to have an Excel file or something to monitor the compliance with various items.

Lycoming allows one to exceed the interval by five hours; as usual, not to be used as a 'planning tool'.

Lycoming states it is four months in case you won't gather the flight hours. Nowadays they are more specific, stating that the oil should be changed at four-month intervals if the airplane has not accumulated 25 hours in 4-month time period.

Interestingly, when using non-leaded fuel in accordance with applicable procedures, Lycoming's recommendation for oil change interval is extended to 100 hours (SL L270).

-Esa

[dscott3984]

I have an excel spreadsheet I use for my actual Cherokee so once I modify that for an A2A bird, I’ll share it here.