Date: Sun, 23 May 2004 18:52:43 +0100 From: Johannes H Andersen <johsnospamfitter_spam_gets_fried.com> Subject: Re: I'm amazed at the difference, different oil makes.
"Henrik B." wrote: > > "**-**" <nospamnospamte.com> skrev i en meddelelse > news:2hbr1gFb767bU1nospamberlin.de... > > > > But the oils have the same thickness when warm at operating temperatures > > > defined as 210F, this the grade 40 bit. > > > > "when warm at operating temperatures" Being the operative sentence there. > > Think about it! > > Meaning? Operating temp is when the oil is at it's thinest. Sp wether you > use a 5W-40 or a 10W-40 grade oil, won't make a differance - the oil will > still get out of the seals.... > > Cheers! Quite. The 5 or 10 bit is the grade at 0F. A low grade number in this place helps the cold starting, but the oil always gets thinner with temperature. A single grade oil, say grade 40W-40 will have a huge variation of viscosity and would be very sticky at 0F. Multi-grade reduces the viscosity variation, but you end up at the same (temperature, viscosity) point as 5W-40 at 210F.