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Title: Engine oil? Post by: Tas131 on February 19, 2009, 10:02:45 AM After reading the gearbox oil thread, I was wondering about the numbers used to indicate engine oil viscosity. What does 15W/40 or 20W/50 etc. actually mean?
Title: Re: Engine oil? Post by: MarkoH on February 19, 2009, 10:09:10 AM After reading the gearbox oil thread, I was wondering about the numbers used to indicate engine oil viscosity. What does 15W/40 or 20W/50 etc. actually mean? You can find some information here: http://en.wikipedia.org/wiki/Motor_oil Title: Re: Engine oil? Post by: miro-1980 on February 20, 2009, 01:49:37 AM WELL, WKIPEDIA SAYS:
" ...Grades The Society of Automotive Engineers, usually abbreviated as SAE, has established a numerical code system for grading motor oils according to their kinematic viscosity. SAE viscosity gradings include the following: 0, 5, 10, 15, 20, 25, 30, 40, 50 or 60. Some of the numbers can be suffixed with the letter W, designating their "winter" or cold-start viscosity, at lower temperature. Viscosity is graded by measuring the time it takes for a standard amount of oil to flow through a standard orifice, at standard temperature. The longer it takes, the higher the viscosity, and thus higher SAE code. Note that the SAE operate a separate viscosity rating system for transmission oils which should not be confused with engine oil viscosity. The higher numbers of a transmission oil (eg 75W-140) do not mean that it is necessarily higher viscosity than an engine oil...." Title: Re: Engine oil? Post by: Thotos on February 20, 2009, 02:02:35 AM ... SAE operate a separate viscosity rating system for transmission oils which should not be confused with engine oil viscosity. The higher numbers of a transmission oil (eg 75W-140) do not mean that it is necessarily higher viscosity than an engine oil...." And as I've said before, a 90 gear oil has the same viscosity as a 30 engine oil. Title: Re: Engine oil? Post by: jasonh131 on April 18, 2010, 08:02:21 PM so what do we put in our cars ,,,,
i bought some asda semi synthetic 10w40 ?12.99 for 5lts as it last a while and doesn't brake down but i've seen this gtx high millage 15w40 which says it conditions hardenend seals http://cgi.ebay.co.uk/CASTROL-GTX-HIGH-MILEAGE-15W-40-4LITRE-ENGINE-OIL_W0QQitemZ270531853760QQcmdZViewItemQQptZUK_CarsParts_Vehicles_CarParts_SM?hash=item3efcf47dc0 (http://cgi.ebay.co.uk/CASTROL-GTX-HIGH-MILEAGE-15W-40-4LITRE-ENGINE-OIL_W0QQitemZ270531853760QQcmdZViewItemQQptZUK_CarsParts_Vehicles_CarParts_SM?hash=item3efcf47dc0) Title: Re: Engine oil? Post by: mirafioriman on April 18, 2010, 08:36:01 PM I usually use Castrol GTX 15/40 in my older cars. Never had a problem with it so I keep using it.
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