How Cold Temperatures Affect the Oil

Oil that’s too thin, will not provide sufficient protection for your engine. Oil that’s too thick will keep your engine from starting in cold weather because the thick, gooey oil challenges your battery and starter motor to spin the engine fast enough for it to fire. So, check your owner’s manual and choose oil viscosity accordingly.

However, many people are surprised to learn that winter weather also puts extra demands on your oil filter. At 20 degrees Fahrenheit, most oils have the thickness of maple syrup. So when your engine first starts up, your engine’s oil pump forces cold, thick oil through all the passages in your engine, including those in your oil filter. A number of factors determine if the oil will find its way through the filter to provide lubrication to your engine, while particulates are filtered out.

There are three specific design elements engineered into filters that help them perform properly in winter weather:


On start-up in cold weather your engine will experience an initial surge of pressure. This pressure could compromise oil filters at their weakest point and could manifest itself as a blown-out sealing ring, a split crimp, or even a burst canister.


Special spring-loaded bypass valves were invented so that, if the filter goes unchanged for an extended period of time and is blocked with debris, unfiltered oil can flow to the engine, providing at least some lubrication – although with dirty oil. Instead of a reliable coil spring, some filter manufacturers may scrimp by substituting “spring” steel that may not return to its original shape after cycling. The result can be unfiltered oil for as long as the filter is in place, with potentially terrible results.


Finally, most important, the filter must remove the smallest particles while offering the least resistance to oil flow. So, treat your car to fresh oil and a new oil filter in winter. It takes only a few dollars, but the life you save may be that of your engine. Also remember to bring the vehicle in at any time if you start to notice something out of the norm with it. This can help your vehicle to last longer and more efficiently as you drive.



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