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Engine Oil

Aeroshell 15W50, stuck valves and cam corrosion, oil temperature issues

This came up recently in the Socata owners’ group where somebody got severe valve problems in an IO540.

Mike Busch says here

Now, this could be the old “99.3% of people who got killed in a car crash had milk for breakfast” thing… Or it could be the old problem in social research – an unidentified 3rd factor which drives the obviously visible correlation.

For about 10 years I used to run 100% 15W50, for a period alternating with 100% Exxon Elite (no significant difference in oil analysis so I stopped Elite because of the famous watery sludge) but nowadays run 50% W80 and 50% 15W50 and with Camguard. When the engine was stripped in 2008 for the crank change, there was nothing wrong with it, but then it is the “C” engine with chrome valve guides.

But also his statement “premature cam and lifter distress (generally caused by corrosion during periods of disuse)” merely indicates that 15W50 might not be much good at protecting the engine during long periods of inactivity. “Everybody” knows these engines are very vulnerable to that, and I would say that there is a 100% correlation between trashed camshafts, and engines which suffered months (or more) of inactivity OR their history was unknown/unverifiable (which probably amounts to the same thing because any owner with evidence of regular use will be delighted to deliver it).

Administrator
Shoreham EGKA, United Kingdom

I don’t think that the type of oil is the major factor when it comes to internal corrosion and that lack of use is a major factor along with oil operating temp, and storage conditions.

The number one enemy of engines is water that is produced by combustion, cool running engines such as the Cessna 152 suffer from an inability to evaporate this water because the oil operating temp is not high enough during the winter. Add to this storage in a warm hangar and you have a perfect mix for the water combined with other byproducts of combustion to eat the camshaft and barrels below the piston rings ( the result being stepped bores and piston pin plug problems ).

The key to avoiding these problems is regular use, getting the oil temp above 180F for at least 45 min each flight and changing the oil at least quarterly. Storage in an unheated but temp stable dry hangar will also help.

Having doubled the use of my Cessna 152’s over the last year I have seen a marked improvement in the cleanliness of the oil filters indicating a lack of metal removed by internal corrosion.

For the private owner the message is clear, you need to use your aircraft and if you are not using it perhaps it is time to let a trusted friend use it when you are not, I have recently seen a private aircraft that has 500 hours on the engine and last year it was only flown wetween the maintenance shop and the owners hangar, internal corrosion is evident and I don’t give the engine very long before camshaft failure. If the owner had flown the aircraft reguarly the chances are the engine would be in a lot better condition so even if they let someone fly the aircraft for 150 hours a year ( and the renter only paying for the fuel ) the owner would be better off than seeing an engine failure in the next 100 hours or so and the £20k bill that the corrosion related engine failure would bring.

My IO540 runs on equal amounts of Total D80 and 15W50 plus 5% Camguard. Oil analysis shows normal readings now, although the aircraft had a long period of inactivity with the previous owner and if an engine problem arises, it will be that inactivity that will be the cause.

Take the rocker box covers of a C152 at anytime of year and you will find plenty of Condensate inside. Everyone I have seen has corrosion inside the cover.

The message is clear from MB and others that you need to FLY your aircraft regularly to prevent engine deterioration/corrosion. Ground running is not good enough either. It must be flown to burn/evaporate off water and acids that accumulate.

That’s great until you hit a prolonged maintenance problem and the plane is on the ground for a long period and then there is nothing you can do. The joys of aviation.

EGLK, United Kingdom

Some folk advocate Marvel Mystery Oil as a panacea – it seems easier to locate than Camguard.

Agree with the use it or lose it philosophy, also applies to flying currency.

Oxford (EGTK), United Kingdom

My IO540 runs on equal amounts of Total D80 and 15W50 plus 5% Camguard

Same here.

According to a US oil expert I know, TOTAL (as sold in France) is Aeroshell with “TOTAL” on the bottle.

Some folk advocate Marvel Mystery Oil as a panacea

I heard MMO was totally discredited after some recent US regs required publication of ingredients and it showed it to be pure snake oil.

I get Camguard here

Administrator
Shoreham EGKA, United Kingdom

My IO540 runs on equal amounts of Total D80 and 15W50 plus 5% camguard

Where does this mix come from?
What is the aim of mixing monograde with multi grade? What is your OAT range with such a mix?

LFPE

See various previous threads on e.g. Camguard.

Shell 15W50 eats engine seals.

OAT range doesn’t really come into it, due to thermostatic control of the oil temperature. The engine merely has to start OK.

Administrator
Shoreham EGKA, United Kingdom

Peter wrote:

According to a US oil expert I know, TOTAL (as sold in France) is Aeroshell with “TOTAL” on the bottle.

is it. I always heard that Total was recycled oil hence the cheaper price

Bathman wrote:

I always heard that Total was recycled oil hence the cheaper price

Possible, I guess, but it wouldn’t make it any worse because the reason you change oil is contamination, not because the lubricant itself degrades. If you remove the contaminations and possibly put in the additives again, the oil should be as good as new.

ESKC (Uppsala/Sundbro), Sweden

@peter
“Shell 15W50 eats engine seals.”

But you said previously that in 2008, after almost ten years of 15W50 use, the engine didn’t show any evidence of wear to be linked with the oil ?

I use Aeroshell 15W50 only. Try to fly or to rent the plane if not able to. No sign of wear during maintenance / oil filter opening. Just made the first oil analysis, waiting for the results.

Last Edited by PetitCessnaVoyageur at 05 Sep 08:35
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