Question Oil change - flight time vs calendar time?

[Neal]

Sadly I have not flown much the last 6 months, in duration at least. Been doing shorter flights probably from dealing with my tail wheel shimmy which I finally resolved. My last oil change was July and that is SIX (ugh) TACH hours ago. I typically change my oil at around 25 TACH hours. The oil still looks new, no darkening or discoloration, obviously. Lycoming recommends 4 months as max duration (calendar).

What are the opinions on oil changes in scenarios like this where it's a calendar vs. engine runtime issue?

Yeah yeah, the saying is the cheapest thing you can put into the plane is oil....

 

[Cactus Charlie]

I sold my PA-28-180 with over 3,000 hours since overhaul. Oil was changed at 50 hours or 12 months. Once I had the FX-3 12 months came first.

My FX-3 is changed at 50 hours or 6 months.

I live in Arizona where condensation build up is a non-issue. I pulled cylinder 3 of that PA-28 at 2,800 hours. The 3 visible cam lobes and followers were bright, shinny, and perfect.

Note that Lycoming qualifies the 4 month interval with this note -

"** Oil change intervals must not exceed 4 months if the aircraft has not been flown for at least 25 hours in a 4-month period. More frequent oil changes are recommended if the engine has been exposed to volcanic ash, particulate, sand, dust debris, extreme weather conditions, or salt spray in coastal environments."

 

[Neal]

Guess it's time to change the oil. What a waste

 

[ve6yeq]

I just added another qt of W100 and 1.6 oz of Camguard before the last flight, as the level was getting low, and I am using about a qt every 15 hours at present. With only 5 hours left before the change (which will be 35 hrs and almost 3 months - the limit that Camguard recommends), I too have the same feeling of am I wasting "good" oil?

 

[Neal]

I just added another qt of W100 and 1.6 oz of Camguard before the last flight, as the level was getting low, and I am using about a qt every 15 hours at present. With only 5 hours left before the change (which will be 35 hrs and almost 3 months - the limit that Camguard recommends), I too have the same feeling of am I wasting "good" oil?

If you're getting close I wouldn't add oil. It can actually get far lower than we would ever allow.

I assume you're "not" using AeroShell as you're adding camguard?

 

[ve6yeq]

I assume you're "not" using AeroShell as you're adding CamGuard?

I use Aeroshell W100 and 5% CamGuard Aviation, as I think the additives in Aeroshell W100 Plus are nowhere near as good as those in CamGuard, based on what I have read.

If you're getting close, I wouldn't add oil. It can actually get far lower than we would ever allow.

I know the Cubcrafters AMM says 6-7 qt recommended, with a min of 4 qt, but in my limited experience, if I add more than 6 qt W100 + 10 oz CamGuard during an oil change, it just ends up out the oil sump breather tube. So, on the dipstick, I am operating between about 6 and 5 as measured on the ground with 29" tires, as I have never tried raising the tail to see what effect the deck angle has on the oil dipstick. The dipstick is at the back of the engine, and thus it would appear that it should read higher if the deck angle is higher.

 

[Cactus Charlie]

I know the Cubcrafters AMM says 6-7 qt recommended, with a min of 4 qt

I add 6 at oil change. That puts the level at 5.5 after engine run. I usually don't add any until it drops to about 4.5, sometimes as low as 4 qt, then add 1 qt.

I've been operating Lycoming parallel valve 360 engines for over 25 years. I never had a problem with high oil temperature even in AZ summer heat. My tired old O-360 would blow oil out the breather if run higher than about 6 qt. Never blew oil out of the IO-360 (CC363i) but never had it over 6 qt.

The oil sump is towards the back of the engine and the dipstick angles in and forwards. My gut feel is that pitch attitude would make little difference to indicated oil level. That seems to be supported by this image in which I estimated the dip stick angle.

 

[Neal]

I add 7 and that puts me at 6 where mine remains quite stable. I'm sure it's on the higher side but following what I know from CC.

 

[Neal]

I removed the top cowl to prepare for the oil change I’ll do after this winter storm passes. Then the thought occurred to me. As I only have 6 hours but 7 months I probably don’t need to change the oil filter. Just the oil. Thoughts??

 

[Cactus Charlie]

With low utilization on my PA-28 I sometimes changed the oil but not the filter. Just make an honest log entry and be prepared to justify your decision when it come times to sell.

With the small amount of contamination I find in the filter I suspect it could easily run 100 hours but I've always changed it with the oil on the FX-3.

For the first few hundred hours I cut the filter, flushed the element, filtered off the contaminants, weighed them, and examined them under an x10 microscope. I relaxed a bit after the Lycoming warranty expired.

 

[Neal]

I've been told by some that they don't change the oil filter every oil change but do it every other oil change. I personally don't do that, I change it at every oil change. This time is different due to such low time on the use. I'll think about it. I already removed the cowl and have the filter out. Just think it's a waste.

 

[ve6yeq]

I have been happy with my Challenger reusable oil filter, which I can clean with some 100LL (and sometimes an ultrasonic cleaner) and replace the relatively cheap seal each time. I have only ever found a small amount of carbon particles in the main filter and a small amount of very, very fine metallic dust on the magnet, so it really did not need to be "changed". However, how do you know that without cleaning it?

I just remove it, clean it, replace it with a new seal (which, in theory, you can reuse on condition in the Amateur-built world), and safety wire it, all for the cost of a couple of cups of 100LL, a $14 seal, and a couple of safety wire holes in my hands.

I understand the "filter performance tests," which show the reusable filters as not "filtering" as well as a paper filter, but on the other hand, it appears that most engines die from corrosion and heat, not ultra-fine particles. So I will use the money saved on oil filters on CamGuard and flying as much as I can.

 

[Neal]

I figured I'd see what chatGPT had to say about CamGuard with AeroShell. I think I'll consider adding this and do a run when I go on my longer RV (motorhome) trips.

You said:​

I use Aeroshell 15w50 in my Lycoming IO-360. Should I also add camguard?

ChatGPT said:​

Short answer: you can add CamGuard to Aeroshell 15W-50 in your Lycoming IO-360, but it isn’t strictly required — and there are pros and cons worth weighing.

Here’s the breakdown:

🛠 1. What Aeroshell 15W-50 already gives you​

AeroShell 15W-50 multi-weight oil contains a pretty robust additive package that includes metal passivators / corrosion inhibitors and anti-wear agents (Lycoming-approved LW-16702 or similar) right from the factory. That’s one of the big reasons the manufacturer updated the formulation and doesn’t require a separate additive when using that oil.

In plain English: the oil is already designed to protect cams, lifters, and other internal parts — so adding another product just because you fly this oil isn’t mandatory.

2. What CamGuard does​

CamGuard (also called CamGuard Aviation) is a separate oil additive that’s engineered to supplement your oil with extra protection against:

• corrosion and rust
• wear & scuffing
• dry-start damage
• deposits & varnish
• seal conditioning

It’s FAA-accepted for use in piston aircraft oils and compatible with Aeroshell 15W-50 and others.

So even though AeroShell’s oil already has anti-wear/corrosion chemistry, the CamGuard chemistry is different and broader — focused especially on corrosion and deposits.

3. When CamGuard makes most sense​

You’d especially consider adding CamGuard if:

• Your airplane sits a lot (weeks/months between flights) — corrosion risk increases when oil sits.
• You’re concerned about dry starts or want an extra safety margin.
• You’re chasing the maximum prevention of cam/lifter pitting and deposits.

Owners and shops that fly less often or care deeply about internal condition often add it whether the base oil has additives or not.

4. Things to think about & caveats​

• Aeroshell-brand reps have sometimes suggested it’s “too much” or unnecessary with their oil — but that’s more opinion than hard technical guidance.
• Some owners report starter adaptor slippage anecdotes when heavy additive packages are mixed — but that’s mostly with Continental engines and isn’t widely confirmed.
• CamGuard won’t replace Lycoming’s required anti-wear chemistries where they’re specifically mandated (e.g., engines requiring LW-16702 under an AD).

Best practice from a maintenance POV​

• If you decide to use CamGuard, add it with each oil change at the recommended ratio (about 1.6 oz per quart) and follow your normal oil change interval.
• If you fly often (weekly, multiple times per week), the incremental benefit is likely smaller than if you fly infrequently.

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Bottom line: AeroShell 15W-50 already has good anti-wear/corrosion additives so you don’t have to add CamGuard. But many owners choose to add CamGuard anyway — especially if they fly infrequently or want extra peace of mind against corrosion and dry-start wear.