Hey guy's - So I was out at the airport the other day and my hangar neighbor was changing his oil. He put in aeroshell straight 50wt and then dumped a bottle of Lucas Oil Stop leak. I didn't think you could do that with aircraft engines? His engine is a lycoming 0-360 with 2340 SMOH. He said he's been putting the stuff in for the last 1000 or so hours and the engine runs better and doesn't leak.

Thought I'd get your opinions.

Jim

If you can trust what he told you, then I'd say it must work. I have heard there are some unapproved fuels that also work well.

If it's a certificated aircraft, and the product isn't TSO'd, it shouldn't (legally) be going in the crankcase. It it's an experimental, it's up to the
owner/operator.

Legalities aside, using stop-leak on an aircraft engine is like patching your cover with duct tape. IMHO, it's probably not a good plan in
the long run. My two cents.

Not sure why the engine would "run better" with leak stop in it. That right there makes me think he is just making stuff up.

I never have liked the "leak stop" anything. Would NOT put it in my plane.

Its got 2300 hrs, its SUPPOSED to leak oil. If its not then something is wrong.

Granted he claims that he has been doing it for a while and it has passed TBO.

However it makes me think of an illustration; just because someone else wandered through the minefield with no issue doesn't mean I can.

But I am no genius so I could be totally wrong. Though, like Rail said, it sounds like a duct tape fix.

Just because I know Pep Boys Pure as gold recycled oil would lubricate an O470 as long as I added a qt of 90 wt gear lube does not mean I will do it. That was the formula I used in a 1934 Ford I had in 1964. But it had a 40 over piston in a 60 over hole

Tim

One of the few "approved" oil additives for aircraft is Cam Guard. Most all the other snake oils out there are no approved, and therefore you're not supposed to use them in a certificated aircraft engine.

As to the time on that engine, one University flight program I'm familiar with runs their Lycoming engines to 2500 hours regularly, and they seldom have to get into those engines or change cylinders before TBO. They use Aeroshell 15 W 50 oil exclusively, and no additives. And, these are engines being used and abused by student pilots and low time flight instructors.

The best thing you can do for your engine is to take it flying regularly. If you can't fly it regularly, add some Cam Guard at each oil change.....the stuff is proven to help prevent corrosion, among other benefits.

But, Stop Leak????? Dumb idea, and probably not good for the internals in that engine.

MTV

jaudette wrote:Hey guy's - So I was out at the airport the other day and my hangar neighbor was changing his oil. He put in aeroshell straight 50wt and then dumped a bottle of Lucas Oil Stop leak. I didn't think you could do that with aircraft engines? His engine is a lycoming 0-360 with 2340 SMOH. He said he's been putting the stuff in for the last 1000 or so hours and the engine runs better and doesn't leak.

Thought I'd get your opinions.

Jim

So think this through. Let's speculate there's an engine failure for any reason and a pax is DOA . Among the things the NTSB does when a fatality or serious injury occurs is an engine teardown and inspection. What's this stuff in the oil ? Hmmm. Next the survivors of the now deceased learn you are stoking the engine with Lucas Oil Stop Leak . How many gazillions do you have to pay off the wrongful death? Just wondering. It might be great stuff? Maybe. In theory a room full of apes can bang out the Encyclopedia Britannica. The odds are better there's a slam dunk case against you and your estate. Just wonderin'.

PapernScissors wrote:
So think this through. Let's speculate there's an engine failure for any reason and a pax is DOA . Among the things the NTSB does when a fatality or serious injury occurs is an engine teardown and inspection. What's this stuff in the oil ? Hmmm. Next the survivors of the now deceased learn you are stoking the engine with Lucas Oil Stop Leak . How many gazillions do you have to pay off the wrongful death? Just wondering. It might be great stuff? Maybe. In theory a room full of apes can bang out the Encyclopedia Britannica. The odds are better there's a slam dunk case against you and your estate. Just wonderin'.

Excellent point.

Really this goes for anything. A guy really has to make sure to cross his T's and dot his I's regarding legal stuff.

If your charts aren't current they could find a way to use that against you.

In any case, using anything not certified (especially on the engine) is risky legally even if its safe mechanically.

Good point! I'm a stickler for following the rules (even though I don't like some of them).

With all the technology out there, I sure would like to be able to use some of it!

Jim

ShadowAviator wrote:In any case, using anything not certified (especially on the engine) is risky legally even if its safe mechanically.

And the "safe" determination isn't of much value if based on a single aircraft, a single engine, and one user's anecdotal account.

What about Marvels Mystery oil? I've heard some of the old timers swear by it in the fuel and oil.

Common for people to run MMO in the oil to clean up sticky rings when you have low compressions. Also some use it in the fuel to help keep valves from sticking with 100LL. I read somewhere it was recommended for some round motors back in the day.
DENNY

Look at the ingredients - it’s mostly solvent. No MMO in any engine I’m operating!

JP256 wrote:Look at the ingredients - it’s mostly solvent. No MMO in any engine I’m operating!

What he said....not approved, and why would you want to run solvent in your engine?

MTV

When the rings get buildup of carbon or other deposits they won't expand and seal properly. As noted the MMO is a solvent and it helps clean the deposits. I am not saying I would do it on a daily basis, just that I have heard of it being used. Is it that much different than adding avgas to dilute the oil for better starting in cold weather (approved and recommended procedure)? Just something to think about. I have tried hard to lean as much as possible on the ground to help prevent lead buildup.
DENNY

General aviation piston aircraft oil is a lubricant and a solvent. For practical purposes all organic hydrocarbons are (in a relative state).

Case study:
1000's of hours of testing concluded conventional oil will dissolve (act as a solvent) lead and carbon deposits better than synthetic oil in an aviation piston engine. That's why Mobile's synthetic aviation piston oil was involved in countless law suits (engine repairs) and was discontinued. Synthetic oil didn't dissolve byproducts well.

Cost of ownership:
It's expensive to synthesize piston oil then synthesis a solvent and mix them together. Conventional oil during refinement retains the natural solvents (needed for lead, carbon etc.) and is a better value to the consumer.

Read the manual and do it:
The balance of lubricants and solvents is a critical element. However, adding solvents is not needed, (opinion) if the manufacture's maintenance requirements are complied with. And of course common sense like adequate preheats. And fly!

Preserving oils are a different discussion.

I use MMO in my fuel and get regular oil samples analyzed. Since starting the MMO I’ve noticed smoother engine operation and my oil samples are coming back good. I️ consider it preventative maintenance against 100LL. I’m also experimental.

CamTom12 wrote:I use MMO in my fuel and get regular oil samples analyzed. Since starting the MMO I’ve noticed smoother engine operation and my oil samples are coming back good. I️ consider it preventative maintenance against 100LL. I’m also experimental.

Run MoGas! If you can get it down there. I tried MoGas in Alaska (GBflyer turned me on to it) loved it! No lead is good, even Lycoming approves it on my serial number! But, it's hard to get in Oregon cosidering how little fuel I use. Opinion.

1) My Maule doesn't leak oil. It is marking its territory.
2) If it isn't leaking oil it is probably out of oil.
3) Tim from Australia says eggs works as a stop leak.

I ask on the MMO because I am buying an airplane that hasn't done much flying to speak of in the last few years. I was thinking about running some on my 16 hour flight back to clean out any contaminants/deposits that may have formed from lack of use.