What is your oil change interval?

Nikhiln25

Nikhiln25

Pre-takeoff checklist
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nikhiln25
I have a 182 for which the manual says with a small filter to do oil change every 50 hours. But then I see people with all different ranges for changes, with some at 25, some 35 some even willing to go a few hours over 50. What gives? When does it make sense to do 25? Is there an optimal range? I’ve been doing every 40 hours (in usually about 3 months) to give my self some buffer but wondering what if it should be a smaller interval
 
I do 50. I don't sweat it if i go a couple over, although I try to get to it before. My reasons:
- Lycoming recommends 50 for my engine
- my engine has a 12 quart sump (filled to 9ish), so there's a lot of oil to dilute contaminants
- I'm cheap
- and lazy
- it's pretty rare for me to not fly once a week, so the engine is never sitting inactive
- I use Camguard (although it's probably pointless, considering the above)
- my old club did 50 hour changes, and their engines always go over tbo
- my 25 hr oil analysis looks a LOT like the 50 hour. It picks up more lead, but the water, fuel, contaminants, and viscosity look almost exactly the same

These engines die from disuse, not insufficient oil change frequency. The bottom ends will easily run 2x tbo with 50 hr changes. I would do 25hr changes on engines with small for displacement oil capacities, like io-550's with an 8 quart sump, or engines without filters.
 
Jim K said:
- Lycoming recommends 50 for my engine
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Yup and 25 if your engine had a screen instead of a filter. But they also recommend every 4 months, whichever comes first.

Oil and Filter Change Recommendations

It has often been said that regular doses of clean, fresh oil provide the least expensive maintenance an owner can give an engine. Lycoming Service Bulletin No. 480 makes these specific recommendations for oil changes under normal operating conditions: A. 50-hour interval oil change and filter...
www.lycoming.com www.lycoming.com
 
Nikhiln25 said:
Is there an optimal range?
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In general, OEMs recommended oil change intervals are determined by filtration type (screen or filter) and type of fuel used. OEM approved unleaded fuel can get you a 100 hour change interval. However, there is also a calendar interval as well if one is following those recommendations.
 
I do 25 hours or 4 months in my Carbon Cub with Lyc IO-360 even thought it has a spin-on filter since that’s what the manufacturer’s maintenance manual says to do (it has a 6 qt sump capacity so maybe thats’s why, I think most IO-360’s have 8). I usually change the filter then to, and cut it open to inspect. I use Aeroshell W15w-50 since that’s also what the maintenance manual says to use. It’s also really easy to change the oil on it. If I still had my 182 I’d be doing 50 hours since I hated messing with the cowl flaps to take the cowling off.

The new rotax XPS 5W-50 oil developed for the 916 would be awesome if it was an ashless dispersant, but I doubt it is, it’s probably a full detergent oil which could hot spot in an air cooled cylinder. I would love a 5W instead of a 15W winter rating. Still it’s only rated for 50 hours if you use it with leaded fuel, I think.
 
25 hours or 4 months for oil, whichever comes first. New filter every other oil change. Oil always changed prior to inactivity, like winter storage.
 
Jim K said:
- it's pretty rare for me to not fly once a week, so the engine is never sitting inactive
- I use Camguard (although it's probably pointless, considering the above)
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I would say the Camguard is "insurance".

Of course, some hold the opinion that insurance is also probably useless.:)
 
asicer said:
I would say the Camguard is "insurance".

Of course, some hold the opinion that insurance is also probably useless.:)
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Exactly. Helps me sleep at night on those rare occasions when I can't fly for a 2-3 weeks.

I don't worry about the four months. Those specs were written for far inferior oils, and also for the worst case scenario like coastal tropics. I'm certain 6 months is fine. Probably more, although for me 4 months and 50 hours usually coincide anyway. I have a few open vented diesel engines that have 5+ year old oil in them, and Blackstone says plenty of tbn, no oxidation... keep running it. Now, those sumps are a LOT bigger, but i don't think the oil degrades much if at all these days from just sitting. Once a year is probably enough for the airplane, but if you're not flying >50 hours a year, you have a utilization problem.
 
I go 90-100 routinely. In 5 different engines now with them flying just about daily in a fleet operation. 100LL Lycoming 320’s and 360’s… They all make 3000 hours minimum, that’s usually just when I like to pull them regardless. Good oil samples, just higher lead content and may not be unusual to ream a valve guide every 700 hours or so for lower compression but that’s just about any situation with a Lycoming.
 
50 hours. Sometimes a little earlier if I'm about to embark on a long trip away from home and I expect to pass the 50 hour mark during that trip. 50 hours was always my mechanic's recommendation in Canada. When I moved to Texas, the mechanic I initially hired for some work recommended 25 hours but didn't have a good reason for why when I asked. It's better for your engine was his reasoning. I think my translation was "it's better for his wallet". The new mechanic I now work with also says 50 hours so back to normal. O-540 engine with oil filter and 12 qt capacity but really only holding 9 qt. Very high time engine but only burning about 1 qt every 8 or so hours.
 
Anywhere from 47-59 hours on a 0-320.
When I was replacing my last engine I ran the oil to 98 hrs and then sent a sample out for analysis. They said it looked good at 98 hrs.
This report was after I had all 4 cylinders off. I cleaned up the rings and put it back together and flew it for another 98 hrs until I had to get it back to Lycoming as a core.
08df6b41-c3a9-45da-bf31-e4ab6ae56493.jpg
 
IO-360, with a filter. Change it at 35-40 hours. Usually closer to 40. Lycoming's 4 month recommendation isn't typically a consideration since I usually hit the hours first. But I have gone as long as 5-6 months prob 3 or 4 times in the 13+ years I've owned her.
 
I'll bet this is one of those buffer + buffer + buffer situations. Engineers at Lycosaur did testing and determined it broke down at 150, so they recommended 100, to be safe. Lawyers chopped that to 50, to be safe. Some owners chop it to 25, because better safe than sorry.

If you do your own changes, it's not a big deal to change every 25. If you are paying labor for each change, yikes! How much are A&P's charging for an oil change these days?
 
Ed Haywood said:
I'll bet this is one of those buffer + buffer + buffer situations. Engineers at Lycosaur did testing and determined it broke down at 150, so they recommended 100, to be safe. Lawyers chopped that to 50, to be safe. Some owners chop it to 25, because better safe than sorry.

If you do your own changes, it's not a big deal to change every 25. If you are paying labor for each change, yikes! How much are A&P's charging for an oil change these days?
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My A&P (outside of nyc) is $150/hour of labor and charges 2 hours for oil change, and 3.5 if he’s going to do spark plugs as well. I’ve found a local A&P for my next oil change to do it with me so I can learn (mainly make sure I do safety wire properly.. I’ve watched videos online how to do it). Though I’m really not looking forward to taking my lower cowling off - putting that on alone is no fun
 
Stewartb said:
25 hours or 4 months for oil, whichever comes first. New filter every other oil change. Oil always changed prior to inactivity, like winter storage.
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Why do you do 25 with a filter? Curious. Is that the recommendation from the mfg?
 
Cessna 182Q we change oil and filter every 50 hours, that’s usually one time between annuals.
Cessna 414, pretty much the same thing, this year I changed it a little over 40 hours and it will probably be 35-40 hours when it’s time for the annual in October.
 
Nikhiln25 said:
My A&P (outside of nyc) is $150/hour of labor and charges 2 hours for oil change, and 3.5 if he’s going to do spark plugs as well. I’ve found a local A&P for my next oil change to do it with me so I can learn (mainly make sure I do safety wire properly.. I’ve watched videos online how to do it). Though I’m really not looking forward to taking my lower cowling off - putting that on alone is no fun
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Yikes. 300 bones every 50 hours is ~12K over the life of the engine. Pretty strong incentive to DIY.
 
Ed Haywood said:
Yikes. 300 bones every 50 hours is ~12K over the life of the engine. Pretty strong incentive to DIY.
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Plus the oil & filter. I think my shop winds up being around $425, and their rate is $107/hr. Sometimes I'm willing to pay that in the winter or when I'm busy and have a trip coming up. My neighbor with the big heated hangar offered its use, so I may take him up on that this winter.
 
Jim K said:
Plus the oil & filter. I think my shop winds up being around $425, and their rate is $107/hr. Sometimes I'm willing to pay that in the winter or when I'm busy and have a trip coming up. My neighbor with the big heated hangar offered its use, so I may take him up on that this winter.
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Just looked up your location. I was going to stop at KCMI enroute to Oshkosh, but wound up getting stuck in Decatur instead. Looks like a good spot for an overnight. College towns always have good food and plenty of hotel rooms in the summer.
 
does the Lyc 4 month interval apply to the newer motor oils? or do aviation oils crap out that quickly?
 
Ed Haywood said:
Just looked up your location. I was going to stop at KCMI enroute to Oshkosh, but wound up getting stuck in Decatur instead. Looks like a good spot for an overnight. College towns always have good food and plenty of hotel rooms in the summer.
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Well, I'd offer to meet up with you, but i go up Thursday so I probably wasn't here. Cmi does have 3 crew cars; not sure what their overnight policy is. Enterprise and maybe hertz deliver to the the fbo. I see Uber and Lyft around town, so I assume that'd work too.

DNV always has the cheapest gas within a couple hundred miles of here, fwiw.
 
Just to add to my 35-40 hour interval on oil changes I mentioned above, I do it myself. And my A&P sells me the oil at his shop’s cost. Filters from spruce. So it’s a relatively cheap oil change.

I suppose if I were paying a shop to do it, I would probably be closer to a 50 hour oil change.
 
Jim K said:
...
I don't worry about the four months. Those specs were written for far inferior oils, and also for the worst case scenario like coastal tropics. I'm certain 6 months is fine. Probably more, although for me 4 months and 50 hours usually coincide anyway. I have a few open vented diesel engines that have 5+ year old oil in them, and Blackstone says plenty of tbn, no oxidation... keep running it. Now, those sumps are a LOT bigger, but i don't think the oil degrades much if at all these days from just sitting. Once a year is probably enough for the airplane, but if you're not flying >50 hours a year, you have a utilization problem.
Click to expand...
Below is a March 2013 Blackstone article on oil acidity:
https://www.dropbox.com/scl/fi/dd62...port.pdf?rlkey=o9es2w7mcvxcpwhexsveuzelu&dl=0
 
Start thinking about it at 35 hours,will go to 50 if I don’t have a long cross country scheduled.
 
What oil are you guys using? I recently put W100 Aeroshell in my IO-470 because it’s easily available locally - any reason to use this or anything different?
 
I usually do 50hr changes, or 6 months if not flying much, and especially if I've had very many flights under 45-60min. Which is pretty rare as I try to get the engine to temp for that long, but it does definitely occur.

Usually use Aeroshell 15w-50, as I need the additive per AD, but I've been trying out the Phillips Victory for the last two warm weather changes. It has the additive as well, and is significantly less expensive. It's also 20w-50, and 'per some online tests' is thicker at cold temps, hence the warm weather use only.

I haven't sent anything in for Analysis so no data there.
But, on the borescopes at annual, for the first time, we saw a tiny bit of surface rust on the cylinder walls. This was after 3.5 weeks of not flying, and also the last few prior flights were short, due to weather, work, etc. (Feb.)
Upon seeing it, I quickly took the plane up for about 90min, drained the oil overnight, then added fresh oil and filter.

That never happened with the Aeroshell. Even under the same conditions, the cylinders were beautiful.
None of that is scientific proof in any way of anything, but enough for me to switch back to Aeroshell. Maybe the additive package is different, I'm not sure.
Either way, if I were to continue to use Phillips Victory, I would start adding Camguard, which brings the price up closer to Aeroshell, with which I have never used Camguard, and don't intend to unless I see some evidence it's needed.
So all things considered, Aeroshell it is...and more flying :)

Also, seeing the rust did motivate me to go ahead and test my oil temp sensor/gauge readings, as suggested by @Dan Thomas.
It was in the ideal range (woot), and wasn't hard to do, at least on the 172, and helped me sleep better in flight at night.
Highly recommend.
 
The engine you maintain, the locations you fly and how often you fly go into the mix.​
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For a Lycoming engine with an oil separator in a moderately humid climate that goes weeks without flying, I like 25 hour changes, single grade summer, multigrade winter and filter changes every 50. The summer / winter change is a bit of calendar timing as much as hours.​
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If I was flying the wings off in Arizona, I’d do 50 hours.​
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Every 50 om my Commander 112A running the Lycoming IO-360 C1D6 200hp. I also run camguard with the Phillips XC 20W50.
 
O-360 with a Hartzell prop, as was my last plane. I do 50 hour intervals, with Phillips XC 20W50. I use the Phillips oil because it’s the lowest-priced. I’d be fine with Aeroshell, and fine with straight 100 (SAE 50). We don’t get more than five or six mornings a year that the temp is below 40 when I fly, and not even that many below 50.
 
I also run CamGuard with Phillips XC 20W50.

Juicing oil with CamGuard:
- 1.6 ounce/quart is 47.4ml Camguard per quart of oil.
- Each 16 oz bottle of CamGuard will treat 10 quarts of oil.

When I get a new case of Phillips X/C 20W50 oil, I pretreat each quart with CamGuard. Open the quart bottle and use a needleless 50 ml syringe to squirt the CamGuard into the bottle neck, reseal, and mark each treated bottle with a black felt-pen 'C'. That way I never need to think about it and the few quarts of oil I carry in the plane are ready to drink. And it's not rocket science, 45-50ml is fine.
 
Oil gurus: I changed my Conti O-300 oil at 50 hrs, and left the old oil in a bucket for a week. When I took the time to dump it, I found the bottom had black sludge that settled out. No particulates. Just a darker thicker looking oil. Is that normal?

Oil filter had some carbon in it, maybe half a #2 pencil eraser amount.
 
Domenick said:
I also run CamGuard with Phillips XC 20W50.

Juicing oil with CamGuard:
- 1.6 ounce/quart is 47.4ml Camguard per quart of oil.
- Each 16 oz bottle of CamGuard will treat 10 quarts of oil.

When I get a new case of Phillips X/C 20W50 oil, I pretreat each quart with CamGuard. Open the quart bottle and use a needleless 50 ml syringe to squirt the CamGuard into the bottle neck, reseal, and mark each treated bottle with a black felt-pen 'C'. That way I never need to think about it and the few quarts of oil I carry in the plane are ready to drink. And it's not rocket science, 45-50ml is fine.
Click to expand...
I do exactly the same, 20/50XC with CamGuard. I forego the syringe and pour directly from the CG bottle into each quart of oil; the graduations on the side of the CG bottle are close enough for gubment work.
 
Hobbs hours or Tach hours? The difference can be significant - 50 Tach hours could be 60 Hobbs hours.
 
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