12-26-1998 Ask Mike! Archive
It's getting cold, what oil should I use?

Dear Mike,
 
What do you think about using a multi-viscosity oil in the winter?

Scott
 
 
Scott:

Whichever oil you choose, straight weights or multi-viscosity, you should stay with year around.  The engine tends to build up ash (dirt) in the crankcase due to combustion by-products and general dirt deposits not being drained with the oil at change time.  Shell's 15W50 is an excellent oil for year around use; some of the lower horsepower engines (such as the 100 HP engine in my 150), use only grade 80 (sae 40) year around.  Higher horsepower engines should use grade 100 or 120 (sae 50 or 60) in the hotter weather.  If you travel much between climates during the winter (Minnesota to Arizona, for example), I recommend multi-viscosity year around.  If you live in Minnesota April thru September, and the rest of the time in Arizona, stay with 100W Aeroshell.  Also, it's a good idea to consult your engine operators handbook.
 
Gear Green,
Mike