(BPT) – Most vehicle owners know it is important to regularly have their motor oil changed. Many owners may not know that choosing any oil weight other than the one specified in their owner’s manual could damage their engine.
“My dad taught me to switch oil weight depending on the season and the driving conditions. I used 10W-40 or straight 30 weight oil in the summer and switched to 10W-30 in the winter,” says RockAuto.com Vice President, Tom Taylor. Conventional wisdom for old cars said oils with higher weight numbers had a thicker viscosity that would make them better for hot weather and hard driving while lighter weight oils were better for cold weather.
The newest engines are often designed to use only one specific oil with a weight number that may be unfamiliar, such as 0W-20 or 0W-40. Doing something like substituting “heavy duty” 20W-50 for 0W-20 in the summer could quickly result in big repair bills.
Oil does much more these days than simply lubricate and cool the engine. Engine oil may act like a hydraulic fluid in engines with variable valve timing, cylinder deactivation or other new systems that are pressure sensitive and route oil through tiny orifices. “We see variable valve timing solenoids that are clogged by dirty oil, but they also get clogged by clean oil that is just the wrong viscosity,” says Taylor.
Using the right weight oil is made more difficult by all the gas stations and convenience stores that still sell 10W-30 for old cars but do not have the shelf space to stock the many different oil types for newer cars. Do not top off your engine with the incorrect oil because that is all a store carries.
Also, do not choose 10W-30 simply because it is less expensive. Newer engines may take seven or 10 quarts of oil. When buying that much oil, it can be tempting to buy a cheaper weight. Putting the wrong oil in your engine could cost you much more money down the road. “Imagine an engine oil pump designed to circulate seven quarts of low viscosity 0W-20 oil rapidly around a motor now struggling to move some witch’s brew of various weights,” says Taylor.
If you hire a shop to change your oil, then make sure they use the correct oil for your engine. Always wait until you can get the oil weight specified in the owners manual.