Winter Weight Oil, Cranking and Lubrication
Posted: Sat Dec 01, 2012 1:24 pm
Something about winter weight oils quite frequently overlooked is that its not all about cranking and starting.
Discussion seems to focus on cold weather cranking speed and success of starting using various winter weight oils leaving engine protection once the engine starts on the back burner.
One of the worse things you can do to an internal combustion engine is put it to work (anything above no load low idle) before the oil begins to completely circulate throughout the system.
How fast that happens is determined by what you pour in your crankcase.
A cold engine with no or very low oil pressure for the first several seconds will suffer only infinitesimal bearing wear as long as no load is placed on the engine and the oil hasn't outlived its useful life.
Oil residue remains on the bearing and thrust surfaces from the last run, protecting from metal to metal contact for a brief period of time after starting, another property incorporated into oils.
Over time, cold weather wear will contribute to bearing and thrust surface wear increasing tolerances, lowering oil pressure. This however should take dozens of years on ag equipment if proper cold weather starting procedures are followed and proper winter weight oil has been used.
The thing to remember is winter weight oils weren't exclusively refined for faster cranking but circulation as well.
If your cranking system is in good health, you may not need to drop down to a zero winter grade, it may crank fine with 90 weight in the sump, but how much oil circulation would you expect to have in the first half hour?
The lowest expected ambient air temperature in your region should be the only gauge used when determining the oil grade your engine will either protect itself with or destroy itself with.
The picture below depicts engine bearings damaged from cold starting.
Discussion seems to focus on cold weather cranking speed and success of starting using various winter weight oils leaving engine protection once the engine starts on the back burner.
One of the worse things you can do to an internal combustion engine is put it to work (anything above no load low idle) before the oil begins to completely circulate throughout the system.
How fast that happens is determined by what you pour in your crankcase.
A cold engine with no or very low oil pressure for the first several seconds will suffer only infinitesimal bearing wear as long as no load is placed on the engine and the oil hasn't outlived its useful life.
Oil residue remains on the bearing and thrust surfaces from the last run, protecting from metal to metal contact for a brief period of time after starting, another property incorporated into oils.
Over time, cold weather wear will contribute to bearing and thrust surface wear increasing tolerances, lowering oil pressure. This however should take dozens of years on ag equipment if proper cold weather starting procedures are followed and proper winter weight oil has been used.
The thing to remember is winter weight oils weren't exclusively refined for faster cranking but circulation as well.
If your cranking system is in good health, you may not need to drop down to a zero winter grade, it may crank fine with 90 weight in the sump, but how much oil circulation would you expect to have in the first half hour?
The lowest expected ambient air temperature in your region should be the only gauge used when determining the oil grade your engine will either protect itself with or destroy itself with.
The picture below depicts engine bearings damaged from cold starting.