Jet lube as an engine treatment.

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Feb 20, 2004
Dearborn , Michigan
Yeah, you never know when someone might have some good advice.
I'm far from an expert but the "ester" theory would seem to explain the dramatic effect.
I spent almost nine years flying jets in the Marines. That doesn't make me a jet engine mech, but I have spent a fair amount of time with a bunch of the real ones. For you USAF guys who are wondering about this, keep in mind that we didn't have separate "maintenance squadrons," all basic and some I-level functions for USN/USMC aircraft are performed by folks assigned to the flying sqdn.

Anyway, I've talked engines, oils, hot rods, you name it with these guys. A few times I heard the story about the guy who had tried the jet engine oil (we used MIL-L-23699 for the most part) in his car engine, and the story always ended up the same way: prompt destruction of the victim engine. Keep a couple things in mind. First, this stuff is of very low viscosity; it looks like and almost runs like water. A little thicker, but not by much. Second, and I think more critically, it's designed to lube and cool very high speed, very hot bearings in an environment never polluted by blow-by combustion gasses. To my understanding, it has zero ability to neurtalize acids that result from blow-by.

I would be very cautious about trying this, and would probably save it as a last resort after all other modes of cleaning had failed and I had little or nothing to lose by trying it. I would never use jet engine oil in a good engine as a routine cleaner. Yes, I know how esters are naturally good cleaners, but I think there's also a good chance of finding a cure that's worse than the disease.

added to an old Chevy truck. It ate out every sela and leaked old Chevy truck that leaked oil.
It MUST have been the jet-lube.
I wonder what else the guy put in the truck over time. For the record, I am not saying 100% jet-lube, just 1 quart. I'm still open to it being a good cleaner.
I snagged a quart of jet turbine oil that was sitting in the waste disposal area from work one time and ran it in my lawn mower. The viscosity worked out to be a 20 weight. The engine ran fine all summer long except it did start to leak oil. Also, it would consume the oil a bit because I could smell it burning in the exhaust as I walked behind it.

I still have that lawn mower but it's happily running on Shell Rimula SAE30 and not leaking a drop anymore.

It would probably be safe to use at a few ounces per fill but I certainly wouldn't use it full strength. It's pricey and not meant for the internal combustion engine.
Just a note on jet engine oils. Turbojet engines don't have journal bearings like auto engines. All of the bearings are ball or roller bearings. The oil is there as much for cooling purposes as for lubrication and some areas of a jet engine can get very hot, which is why they use synthetics. A rolling element bearing doesn't need a high viscosity lubricant the way an auto journal bearing does.
This is AeroShell 560 turbine oil third generation


DENSITY @ 15°C kg/L 0.966

VISCOSITY AT 100°C mm²/s 5.25

VISCOSITY AT 40°C mm²/s 28.0

VISCOSITY AT -40.0°C mm²/s 10100



TAN mg KOH/g 0.10

US MIL-L-23699D Approved

British DERD. 2499
NATO O-156

Joint Service Designation OX-27 OX-28

Pratt & Whitney 521c Type II

General Electric D-50 TF1

Allison EMS-53

It appears to show up as a high 10 weight between 40C and 100C ..very stable between those temps.

Could this be just the thing for those who suffer in the Canadian winters???
Jet engine lubes, as stated by Gary and others, are approx. 10 cSt oils. The base oils may be a mix of one or more of the following esters or compounds of esters: pentaerithytrol (PE), Di-pentaerythritrol (Di-PE), tri-pentaerythritrol, tetra-pentaerythitrol, Trimethylolpropane (TMP), Tremethylolethane (TME), diesters, and or complex esters.

The additive package is primarily high temp and very expensive antioxidants with rust inhibitors and low levels of anti-wear agents.

Because these esters are agressive to seal materials commonly used in gasoline engines, special seal materials are used.

Hence, synthetic jet engine oils should not be used in IC gasoline or diesel engines.
As a former employee of Canadian Airlines Int(CP).
..had a very similar conversation with one of our base mech...-one chap used in his car- destroyed every seal...

Talking to an old-school used car lot salesman I know. He said for the worst sludged, leaking and burning engines, they would add some jet engine lube @ $12/q to a normal oil change and it would work "every time". Is this esters that does all the "good" in the engine? I know this could have been posted in "Tips" or "additives", but I wanted to discuss it as a lubricating oil issue. Anyone heard of this and how it works? Esters are a componet of jut lube and *could* be responsable for cleaning, swelling of seals and general de-sludging.
Oh boy, the only worse source of advice than the "guy at the parts counter" or the "100 year old master mechanic" is probably the used car salesman.

I grew up spending lots of enjoyable time with characters like those, but I would not put much stock in their expert advice

I would not be so quick to dismiss this one. He could be on to something, the chemistry of esters seems to agree with what we have learned here.
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