I have a high mileage Mazda 2.2. I've been using synthetic 10w30 and 5w30 in it for a while. My last oil analysis showed higher than normal lead and copper - probably normal for such high mileage and on that OCI many very short trips in very cold weather (-15C or colder, 3 km trip)
Anyway, I was thinking of using 5w40 Rotella on my next change to give the engine a little thicker oil - given than it has very high mileage and the tollerances inside are probably quite larger than when new. This would help cusion the main bearings etc. and hopefully help her out a little as those bearings start to show wear in the UOA.
However, this got me thinking, maybe 5w50 would be better for the same reasons. I do live in a cold climate, winter can reach -25C or colder regularly, so the 5w is important at startup. But the 50w could be even better for the worn out engine when at temperature. Both 5w40 and 5w50 Castrol are on sale at a local store. I've looked around and it's hard to find 0w here.
Any possible risks or downsides to using 5w50? Maybe I should look harder for a 0w40 - maybe that would overall be better given the climate conditions?
Anyway, I was thinking of using 5w40 Rotella on my next change to give the engine a little thicker oil - given than it has very high mileage and the tollerances inside are probably quite larger than when new. This would help cusion the main bearings etc. and hopefully help her out a little as those bearings start to show wear in the UOA.
However, this got me thinking, maybe 5w50 would be better for the same reasons. I do live in a cold climate, winter can reach -25C or colder regularly, so the 5w is important at startup. But the 50w could be even better for the worn out engine when at temperature. Both 5w40 and 5w50 Castrol are on sale at a local store. I've looked around and it's hard to find 0w here.
Any possible risks or downsides to using 5w50? Maybe I should look harder for a 0w40 - maybe that would overall be better given the climate conditions?
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