90w-140 oil?

[Sponsonwalker]

Locally I found a store that sells 90w-140 oil. Will this work in my Seagulls lower units? They are all supposed to use the straight 140, so I thought I would ask before trying this out.
Thanks.

[charlesp]

No. If it's a model that uses straight 140, then you should use straight 140.

[Stelios_Rjk]

If you go to a store that sells lubricants ask for multigrade mineral oil 140, for manual gearboxes and axles, that meets the specification: API GL-1
If he don't understand try another store. At least that was what I did.

[charlesp]

Don't ask for a multigrade, ask for 140. If you ask for a multigrade they'll sell you a multigrade.

[Stelios_Rjk]

What's wrong with multigrade since it meets the API GL-1 specification?

[Charles uk]

Why not ask for SAE 140 as it's described in the Seagull user guide.

[Stelios_Rjk]

I find difficulties when asking for SAE 140 so I searched for the specifications to finally get what is needed for the gearbox.

[charlesp]

If you're using a multigrade you're not using the type specified...

[albert]

Multigrade is something like SAE 80w90 or SAE 85w140.
Seagull tells you to use SAE140 and that is a single grade.
Millers oils and Penrite have it.

[Stelios_Rjk]

Don't know what to say. Mine says API GL-1-140 multigrade. From www.deleklubes.com

[charlesp]

Sadly that website is all Greek to me.

But I stick with my assertion that a straight 140 grade is the right oil to use.

[Keith.P]

I think this site says is the second largest oil company in Israel, it was founded in 1951and provides about 30% of oil used.
So they must do straight 140 grade.

[Sponsonwalker]

Okay, thanks. I'll keep looking for 140.

[Vic]

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Some info to explain the meaning of the API rating and the SAE viscosity grading:


What does API GL mean?
API stands for American Petroleum Industry and GL stands for Gear Lubricant, see below for
their definitions:

API GL-1 Straight mineral oil
API GL-2 Mild EP for worm gears
API GL-3 Mild EP for spur and spiral bevel gears in axles and transmissions
API GL-4 Medium EP, MIL-L-2105 quality, moderate severity hypoid gears, manual transmissions
API GL-5 High EP, MIL-L-2105D quality, all hypoid axles, some manual transmissions
API GL-6 Extra high EP, now obsolete

Is it important to select the right API GL rating?
Yes. Selecting the correct gear oil performance level will provide the best protection to the
components of the transmission.


What do the SAE grades mean?
SAE stands for the Society of Automotive Engineers. The SAE classification system is a way of
defining how thin or how thick an oil is. This is known as an oil’s viscosity. The classifications
are listed here in order of increasing thickness: SAE 75W, SAE 80W, SAE 85W, SAE 90, SAE
140, SAE 250.

What does EP mean?
EP means extreme pressure and refers to the additive used in gear oils. This additive is
designed to stop metal-to-metal contact taking place between transmission components. The
EP additives are usually based on sulphur and phosphorous. These elements bond to the
metal surfaces where there are points of extreme pressure and temperature, forming a
sacrificial chemical layer. The sulphur gives gear oils their characteristic smell.


Monograde gear oils
Monograde gear oils are designated by one number (70, 90, 140, 250, etc.). The number indicates a level of the oil viscosity at a particular temperature. The higher the grade number, the higher the oil viscosity.
Viscosity of gear oils designated with a number only without the letter “W” (SAE 80, SAE 90, SAE 140 etc.) was specified at the temperature 212°F (100°C). These gear oils are suitable for use at high ambient temperatures.
Viscosity of gear oils designated with a number followed by the letter “W” (SAE 70W, SAE 75W, SAE 80W etc.) was specified at the temperature 0°F (-18°C). The letter “W” means winter. These grades are used at low ambient temperatures.

Multigrade gear oils
Viscosity of gear oils may be stabilized by polymeric additives (viscosity index improvers). Viscosity of such gear oils is specified at both high and low temperature. These oils are called multigrades and they are designated by two numbers and the letter “W” (SAE 75W-90, SAE 80W-90, SAE 85W-140 etc.). The first number of the designation specify the oil viscosity at cold temperature, the second number specifies the oil viscosity at high temperature.
For example: SAE 85W-140 oil has a low temperature viscosity similar to that of SAE 85W, but it has a high temperature viscosity similar to that of SAE 140.


Note the example in the last line above. It means that your SAE 90W -140 oil will have a viscosity similar to that of an SAE 90W oil at low temperatures and only have the viscosity of an SAE140 oil at high temperatures. Seagull gear boxes do not operate at high temepratures

It should also be noted that the viscosity grades for gear oils are different to the viscosity grades for engine oils

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