Filter every oil change?

[FloridaMan]

I've been changing my oil and filter every 25-30 hours. My engine's got over 1400 hours on it and the oil seems to get dirty pretty quickly. I've heard some pilots talk about changing the filter every other oil change. Do any of you do this?

[M016576]

I've been changing my oil and filter every 25-30 hours. My engine's got over 1400 hours on it and the oil seems to get dirty pretty quickly. I've heard some pilots talk about changing the filter every other oil change. Do any of you do this?

Define "dirty". The signs that my engine was coming apart were a combination of the following....

A). Increased oil consumption (1qt every 4-5 hrs from 1qt every 15 hrs)

With

. Oil going from clean directly to black at about 5 hrs. Soot black. Before it just got kind of tan.

Which led to C). Metal in the oil filter. Lots of it.

I never reused my oil filters... I always cut them open: that way I could inspect for metal.

[Jeff_S]

Change the oil, change the filter, including cutting open the old filter to look for metal. It's cheap cheap cheap insurance against a catastrophic engine failure in flight.

[FloridaMan]

Define "dirty". The signs that my engine was coming apart were a combination of the following....

A). Increased oil consumption (1qt every 4-5 hrs from 1qt every 15 hrs)

With

. Oil going from clean directly to black at about 5 hrs. Soot black. Before it just got kind of tan.

Which led to C). Metal in the oil filter. Lots of it.

I never reused my oil filters... I always cut them open: that way I could inspect for metal.

Seems to look almost virgin after about 10 hours. Between 10 and 20 it starts looking like used motor oil. My first oil change was at 41 hours and my A&P prescribed a 25 hour interval with how dirty it was. My consumption is around 1qt every 5-10 hours. I run conservatively ROP -- I try to stay around 75 degrees ROP, but sometimes don't catch it in time and have found myself cruising as much as 200-250 ROP. I'm getting better with it, but I've got feeling the richness is fouling the oil.

[The-sky-captain]

The filter holds a lot of oil. If its not changed it seems to me that it would introduce a lot of old, dirty oil to your new batch. Plus like mentioned before I like to cut each filter and look for metal. Don't forget to check the suction screen as well. It can be a PITB but it will catch large chunks of metal that otherwise wouldn't make it to the filter and lull you into thinking your engine is healthy. This is how I caught my engine issue a couple years back and the spin on was showing all clear

[fantom]

Not changing the filter, opening and inspecting it with every oil change is penny wise and pound foolish. If you must save a few bucks better to go another 5 or 10 hours between changes.

[gregwatts]

My engine has < 500 hrs SFOH.......I drain the oil every 25 hrs and replace with new oil but do a complete oilchange every 50 hrs. I monitor the color of the oil and never let it get that dark.

With 1400 hrs on the engine....I would tend to agree that changing the filter every time is a good idea.

[Hank]

Not changing the filter is not a good idea. Many people do so in their planes, but not in their car even though the aircraft engine costs the same to replace as the entire car.

Every oil change, in every engine, gets oil and filter. Car, truck, airplane, tractor . . .

Do track make-up oil, and cut open your filters.

[AlexR]

Not changing the filter is not a good idea. Many people do so in their planes, but not in their car even though the aircraft engine costs the same to replace as the entire car.

Every oil change, in every engine, gets oil and filter. Car, truck, airplane, tractor . . .

Do track make-up oil, and cut open your filters.

I also change my oil every 25hrs and replace the filter at every 50hrs (cutting and inspecting). Can you explain exactly why not changing the filter every time is not a good idea? Rather than giving my engine old oil for 50 hrs I refresh it at half the interval which gives me a chance to get my oil analyized twice as often (providing a more accurate trend). It also gets the cowl off the engine so I can check for leaks, wear, and anything else that may be going awry. I see no need to replace the filter at an crazy low interval as it would be counter productive and would INCREASE ENGINE WEAR. When you replace the filter, you leave a near half quart gap in the pressurized oil system. This means you wont have oil pressure for nearly double the time upon start up. Most engine wear takes place at start up. Changing the filter while it is still working fine (25hrs) and starting is equal to starting your engine at 20F without preheat....IHMO.

[jetdriven]

If the airplane is flown often, changing the oil every 25 hours, to me, is like topping your plane off, then pumping a gallon on the ground.

[rbridges]

going slightly off subject, I'm changing my oil every 40-50 hours. I've seen debates b/t 25 and 50 hours. The oil was last changed in August and I'm approaching 42 hours. I'm supposed to change it Monday. How many of you are sticking w/25 vs 50?

[1964-M20E]

I change my oil every 50 hours. From what I understand the recomendation of 25 hours is if you do not have the spin on filter.

[Hank]

Every 50 hours, oil & filter. Why change the oil and leave most of a quart of old, dirty oil in the filter to contaminate the 6 quarts of clean oil you just put in? Have you ever changed the oil in your much less expensive car engine and left the old filter on? Lots of goop in the old oil, lubricants are broken down, it all needs to go not just most of it. How long does the oil stay looking clean when you don't change the filter?

[1964-M20E]

Well there is still plenty of old oil in the gening after you drain it and change the filter. I'm not sure how much oil is in the cooler and lines but that oil does not get drined when changing the oil.. Unless I'm missing something.

[FloridaMan]

We cut the first filter 41 hours after I bought the airplane. It was clean, though the oil was pretty dirty. We also drained the oil cooler during that change. Today's oil change was 31 hours since the last change at the end of September. I'm holding on to the filter to cut it as soon as I get a filter cutter. I've put 105 hours on the tach since I took delivery of the airplane in June.

[jetdriven]

Well there is still plenty of old oil in the gening after you drain it and change the filter. I'm not sure how much oil is in the cooler and lines but that oil does not get drined when changing the oil.. Unless I'm missing something.

from experience the oil cooler and lines holds just about two quarts. Interestingly, I discovered my old engine had the oil cooler plumbed backwards. it should have the pressure line at the bottom so it fills bottom up. This chases all the air from the cooler.

[Jeff_S]

There is a lot to be said for longer oil change intervals (based on hours flown) if those hours are coming close together. In my old Warrior I was changing about every 25-30 hours and the Blackstone analyses started to show some signs of metal most likely from corrosion (I think it was iron). It was nothing dangerous, but my A/P said let's just fly the crap out of this thing for the next few months and so I flew it to Colorado and then to OSH and several more trips that summer, and we changed the oil after nearly 50 hours. Dang if the next analysis came back with better numbers.

I find that my flying has curtailed a bit this year due to extenuating circumstances, and even the trips I do still make are obviously much faster in the Mooney, so I am currently on a 4-month/25 hour change cycle.

[larryb]

There don't seem to be anti-drain valves in these oil filters. Depending on how you change the oil, there may not be much/any old oil left in the filter. This is in my 84 J model.

I change my oil in 2 parts:

1) After a flight, put the plane in the hanger and attach the drain hose into a bucket. Let the oil drain, and leave.

2) The next day, come back and finish the job with new filter/oil.

I do this so I get a hot oil drain, but don't have to deal with a hot engine and filter while changing the filter. What I find is that when I remove the filter after the plane has sat, there isn't any oil in it. The nice thing is, you don't create a mess while changing the oil filter.

I change my filter every time so I can open it and check for metal. But for those that don't, if you drain the engine overnight you won't have a quart of old oil in the filter to worry about.

Larry

[Bartman]

I drain the oil over night every 25 hours as mentioned above, and see no reason to change the filter at 25 hours intervals. My IO360 gets a filter change every 50 hours.

I add 7 quarts at all oil changes, keep it about 6 quarts on the dipstick and use about 1 or sometimes 2 quarts in 25 hours. My flights are LOP 2400 RPM in cruise and my oil starts to change color about 15-20 hours. If I go longer than 25 hours on the oil it will need top-off oil much more frequently.

I have discussed this with the A+P and the IA in the shop on my field and they support this approach. They do the 50 hours oil and filter change.

[bd32322]

There don't seem to be anti-drain valves in these oil filters. Depending on how you change the oil, there may not be much/any old oil left in the filter. This is in my 84 J model.

I change my oil in 2 parts:

1) After a flight, put the plane in the hanger and attach the drain hose into a bucket. Let the oil drain, and leave.

2) The next day, come back and finish the job with new filter/oil.

I do this so I get a hot oil drain, but don't have to deal with a hot engine and filter while changing the filter. What I find is that when I remove the filter after the plane has sat, there isn't any oil in it. The nice thing is, you don't create a mess while changing the oil filter.

....

I have the reverse experience - even if I drain for a day or longer - when I loosen the filter I still get some oil - not a gush but a steady drip drip from the engine pad where the oil filter connects ...