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Re: Questions about engine oil.


Why did you change from 5W50 to 5W30?  The 5W tells you what the viscosity
of the oil will be when cold.  The last number tells you what it is when
hot.  Both oils will have similar viscosity when cold, and both are
therefore suitable for winter use.  The 5W30, however, is a bit thinner
than 5W50 when hot, since the lower the number means thinner oil (lower
viscosity).  It sounds as if that caused the light to come on.  It may not
be a problem, but it isn't something I would want to look at very often.

I would change back to the 5W50 if it was my car.

>Hi all,
>I have a questions about the engine oil and hope anyone on the list could be
>kind to help. I used to using the Castrol 5w-50 engine oil for my 5kcst.
>Last week, I changed the engine oil to the Mobil 5w-30, after a 30 miles
>trip the oil pressure lite came on when the car restart. The weather now
>here in Bloomington, Indiana is around 25F to 45F and still no snow yet.
>Also, after I read the viscosity chart in owner's menu and I found that
>the 5w-30 engine oil's temperature range is only form -20F to 20F.
>I am not really familiar with the engine oil therefor my questions are:
>Am I using the wrong viscosity grade of engine oil?
>It that bacause I'm using the 5w-30 oil so that it triggered the oil
>pressure lite?
>   Thank you
>       &
>Happy Thanksgiving
>Albert Ng
>87 5kcst

Richard Funnell, OES
tel. (408) 992-2265
fax. (408) 746-7633