Why do some greases stink?

[MolaKule]

Many of the oils and additives that go into greases are the same oils and additives that are formulated into gear lubes, the only difference being the grease has thickeners such as heavy polymers, clays, PTFE's, etc. Amsoil (and Redline, and Mobil) use heavy esters and PAO's that provide most of the FM and mild anti-wear behavior of the grease. Little of the esters of sulfur and phosphate AW's have to added, but they are still there, just in smaller quantities. Metal soaps of lithium, moly, zinc, and aluminum are added to beef up the EP characteristics.

Schaeffer's greases uses mostly heavy group I oils that are high in sulfur and then adds the additives, which also contain high amounts of sulfurs and phosphates which give it that strong smell. Moly sulfide is of course added as the primary EP additive. Moly sulfide has a strong metallic smell to it, which I explain as the same smell one gets when sharpening a knife on a whetstone.

Greases also contain surfactants and tackifiers, with the latter being used to keep the grease from slinging off lubricated parts.

 

[darrenc]

Thanks once again Molekule. What greases do you like, and why if you don't mind me asking?

Darren

 

[darrenc]

Last night I was conducting a sniff test of three different greases I had on hand. Two where Amsoil synthetic greases (Heavy Duty Moly Fortified - GHD, Multi-Purpose – GLA) and the other was a tube of Schaeffer’s 221. The Schaeffer’s had a strong sulfur odor, like gear lube, and the Amsoil had almost no odor. What is in Schaeffer’s (and every gear lube I’ve ever smelled) that causes the sulfury odor? Just curious.

 

[UncleS2]

I think it's because those dinosaurs have been dead for a *LONG, LONG* Time!

Couldn't resist.

 

[MolaKule]

Well, I am going to be ordering some Schaeffer's grease here shortly to test,
but my current choices are:

1. Amsoil Racing Grease (milky-white, for highly-loaded, slow speed wheel bearings), High-Speed Bearing Grease (red, Aluminum-lithium complex), and their dark blue or purple heavy-duty moly grease (U-Joints).
2. Coastal Marine Grease and Luboron Marine Grease for Trailers and outside farm equipment.
3. Mobil 1 General purpose grease.
4. Luboron General Purpose Grease for chassis lubrication points.

 

[darrenc]

Thanks Kule.

 

[68redlines73]

Here are two questions for the masses:

• Would you think a grease would work better if it had a strong odor vs. not?
• Do you prefer a low odor grease irrespective of performance?

 

[darrenc]

I think the odor is irrelevant unless, of course, a particular odor is indicative of a particular grease component know for its superior qualities.