Cold weather oil in L-134
What oil would you use in a 1949-ish L-134 flathead engine, when the outside temperature is -30°C (-22°F)?
I tried to start the Jeep today in those temperatures, but the battery was toast so nothing happened at all when I pressed the starter button...
But since there was no block heater on, I don't know what would have happened if I had been able to turn it over. I haven't changed the oil since I got it in the summer (I doubt it's gone 20 miles in that time), so I don't even know what's in there right now. But the PO lived in warmer climes--rarely dropping below -10°C (+14°F).
I put a battery warmer on it, and next time I go out to the acreage, I'll bring along a battery charger. Between those, I should be able to turn the engine over. But I should probably put some light weight oil in it, too. What rating would you suggest? I know that modern cars say to use 5W30 all year, and that seems to work fine in all newer cars I've owned, but a flathead is a different beast!