Engine oil ratings and what they mean

[wyze]

What is more important the SAE or the 10w50 oil rating?

Is there a difference between a 10w50 semi synthetic and a 10w50 fully synthetic?

What oil do you use in your cars?

 

[HDi fun]

There was a bit of a dialog on oil some weeks ago - see link below.

http://www.torquecars.com/forums/f8/what-do-you-think-top-oil-brands-3433/

The 10w/50 (in this case) is the SAE rating of viscosity. SAE being the Society of Automotive Engineers.

Others to look at are the API (American Petroleum Institute) and ACEA (European Automobile Manufacturers Association) ratings.

These reflect various qualities of the oil. It's not as simple as just buying the correct grade.

Synthetics are superior to semi-synthetics, which in turn are superior to mineral oils. Beware, not all full synthetics are fantastic either.

I use AMSOIL 5w/40 fully synthetic diesel engine oil which gets an API CJ-4 rating. Previously I've used Millers XFD which is also a 5w/40 fully synthetic diesel oil.

Petrol oils: I rate Halfords fully synthetic 5w/40 which is made by Esso and Morris Oils 5w/30 synthetic.

 

[pgarner]

i use amsoil 5w/35 fully synthetic petrol ( on HDI recommendation ) and i gotta admit its seems good so far.

has been in the car around 4k and is only starten to darken ( not yet black ) where as the Audi/VW long life was the same colour after 2k.
loses the heat pretty quickly - after driving the other day (27 degress outside) my oil temp was holding a steady 220 degrees F (gauge is american) which is 104 C to 195F (90.5 C) in around 45 seconds. dont know if this is any different to other oil as only amsoil with the gauge in place

 

[HDi fun]

mine usually sits over 100 Celcius and the AMSOIL really does seem to stay in grade well. Even after 12,000 miles although it's BLACK (diesel engine's are bastards for discoloring oil) it's working and doing its job well.

 

[pgarner]

the only downside ive got with amsoil is that it claims to be "longlife" however it states that the 25k mile doesnt work for super/turbo charged cars it states that its only good for 15k. OK still k for the normal driver for 1 year.
Looking at changing it shortly if funds allow just to keep it in condition

 

[HDi fun]

If you get samples taken and analyzed you'll find that it will go much longer than 15k. Oil analysis is a good way to keep in touch with the condition of an engine.

I do believe in this stuff, it really does stay in grade for ages.

Perhaps a filter change and top up would suffice ?

 

[obi_waynne]

Where do you get your oil analysed? What sort of things does it tell you then?